Learn Basic Electronics a Handbook for Beginners

Author: GURUPRASAD N H

Published By: GURUPRASAD N H

Copyright © 2024 Guruprasad N H. All rights reserved.

No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior permission of the author.

This eBook is published solely for educational purposes. While every effort has been made to ensure accuracy, the author and publisher disclaim any liability for any injury, loss, or damage resulting from the use of the information contained in this book.

First Edition: 2024

Cover Design, Illustrations and Diagrams: GURUPRASAD N H

About the author

Hello! I am an academic by profession with a passion for education and technology.

With a Master of Science degree in Computer Systems and IT obtained through rigorous research work, I have cultivated a deep understanding of the intricacies of the field.

In addition to my academic achievements, I have also earned several diploma qualifications, including A+ Certification, Embedded Systems, Radio and Television Technology, and an Orientation Course in Children Education.

These diverse qualifications have enhanced my expertise and prepared me to tackle multifaceted challenges in the ever-strengthened world of technology.

For the past 24 years, I have had the privilege of working as a lecturer and as a principal in colleges and universities across three different countries.

This diverse experience has allowed me to connect with students from various backgrounds and cultures, fostering a rich and inclusive learning environment.

Driven by my desire to make education more accessible and engaging, I have embarked on a freelancing journey.

As a freelancer, I am dedicated to designing and developing innovative learning kits for students, providing them with practical and immersive educational experiences.

I offer my expertise in technical courses to cater to the academic needs of clients worldwide.

Through my work, I strive to bridge the gap between academia and technology, harnessing the power of both to empower students and educators alike. I am excited to share my knowledge and insights with readers like you through my books.

Join me on this journey of exploration and discovery as we navigate the ever-strengthened landscape of education and technology together.

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Books from the author

1. Build Switch AND Logic Gates Using Transistors on the Breadboard: Project for Students, Hobbyists, and Electronics Enthusiasts

2. Learn Basic Electronics: A Handbook for Beginners

3. NAND A Universal Gate Build Logic Gates Using CMOS and TTL NAND Gates Study and Verify For Positive Logic: Build On the Breadboard

4. Build FM Modulator and Demodulator Using PLL IC CD4046B on the Breadboard: Project for Students, Hobbyists, and Electronics Enthusiasts

5. Right Way to Build Half Adder and Full Adder Circuits on the Breadboard: Project for Students, Hobbyists, and Electronics Enthusiasts

6. Right Way to Build Half Subtractor and Full Subtractor Circuits on the Breadboard: Project for Students, Hobbyists, and Electronics Enthusiasts

7. Build Frequency Variable Morse code Practice Oscillator on the Breadboard: Project for Students, Hobbyists, and Electronics Enthusiasts

8. Study and Verify TTL Logic Gates for Positive Logic Using 74LS TTL IC: Build On the Breadboard

9. Build and Study RS, D, JK, and T Flip Flops Using TTL Logic Gates

10. The Secret of Logic Gates: Unveiling the Power of LDRs

11. Make Electronic Circuits on Paper with Pencil: Build Simple Basic Electronic Circuits

12. ChatGPT for Arduino: Harnessing the Power of ChatGPT for Your Arduino Projects

13. ChatGPT for Absolute Beginners: A Self-Learning Guide!

14. ChatGPT for Lifelong Learning: an Educator's Toolkit: Empowering Educators and Learners through Conversational AI

15. Watt's Up with Electronics: Basic Electronics MCQs for Inquisitive Kids

16. Finger-Tap Code: A 555 Timer Morse Adventure:  DIY Morse Code Circuit

17. Solderless Breadboard Explorations: Unveiling the Wonders of Electronic Prototyping

18. Kid’s Guide to Logic Gates: Diodes and Transistor Magic Hands-on Circuits for Curious Kids!

19. Decimal to Binary Fun: Light up the Numbers!

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Contents

Chapter 1. Introduction to Electronics

​1.1 What is Electronics?

​1.2 Brief History of Electronics

​1.3 Why is Electronics Important?

​1.4 Conductors

​1.5 Insulators

​1.6 Components

​1.7 Active and Passive Components

​1.8 Symbols

​1.9 Circuits

​​1.9.1 Closed Circuit

​​1.9.2 Open Circuit

​​1.9.3 Load

​1.10 Schematic Diagram

​Multiple Choice Questions and Answers

Chapter 2. Basic Concepts in Electronics

​2.1 Electricity

​2.2 Electric Power Source

​2.3 AC Power Source

​2.4 DC Power Source

​2.5 Volt and Voltage

​2.6 Electric Current

​2.7 Resistance

​2.8 Power

​2.9 Series and Parallel Circuits

​2.10 Ohm’s Law

​2.11 Example Calculations of Ohm’s Law

​Multiple Choice Questions and Answers

Chapter 3. Basic Components

3.1 Switches

​​3.1.1 SPST Switch

​​3.1.2 SPDT Switch

​​3.1.3 DPDT Switch

​​3.1.4 Slide Switch

​​3.1.5 Momentary Push ON Switch

3.2 Resistors

​​3.2.1 Fixed Value Resistor

​​3.2.2 Resistor Color Code

​​3.2.3 Example Calculations of Resistor Color Code

​​3.2.4 Example Calculations of Tolerance Band

​​3.2.5 How to Remember Resistor Color Code

​​3.2.6 Resistors in Series

​​3.2.7 Example Calculations of Resistors in Series

​​3.2.8 Resistors in Parallel

​​3.2.9 Example Calculation of Resistors in Parallel

​​3.2.10 Variable Resistor

​​3.2.11 Light Dependent Resistor (LDR)

​​3.2.12 Thermistor

3.3 Capacitors

​​3.3.1 Fixed Value Capacitor

​​3.3.2 Ceramic Disc Capacitor

​​3.3.3 Capacitor Value Conversion

​​3.3.4 Example Calculation to Convert a Value from nF to pF

​​3.3.5 Example Calculation to Convert a Value from nF to µF

​​3.3.6 Example Calculation to Convert a Value from pF to nF

​​3.3.7 Example Calculation to Convert a Value from pF to µF

​​3.3.8 Example Calculation to Convert a Value from µF to nF

​​3.3.9 Example Calculation to Convert a Value from µF to pF

​​3.3.10 Capacitor Conversion Table

​​3.3.11 Electrolytic Capacitor

​​3.3.12 Capacitors in Series

​​3.3.13 Example Calculations of Capacitors in Series

​​3.3.14 Capacitors in Parallel

​​3.3.15 Example Calculations of Capacitors in Parallel

​​3.3.16 Variable Capacitor

3.4 Inductors

​​3.4.1 Fixed Value Inductor

​​3.4.2 Inductor Color Code

​​3.4.3 Example Calculations of Inductor Color Code

​​3.4.4 Inductor Value Conversion

​​3.4.5 Example Calculation to Convert a Value from µH to H

​​3.4.6 Example Calculation to Convert a Value from nH to µH

​​3.4.7 Example Calculation to Convert a Value from mH to H

​​3.4.8 Inductors in Series

​​3.4.9 Example Calculations of Inductors in Series

​​3.4.10 Inductors in Parallel

​​3.4.11 Example Calculations of Inductors in Parallel

​​3.4.12 Variable Inductor

​​3.4.13 Transformers

3.5 Semiconductor Diodes

​​3.5.1 Light-Emitting Diode (LED)

​​3.5.2 Signal Diode

​​3.5.3 Power Diode

3.6 Transistors

​​3.6.1 Bipolar Junction Transistor (BJT)

3.7 Integrated Circuit

​3.8 How to Identify and Read the Value of Components

​Multiple Choice Questions and Answers

Chapter 4. Electronic Tools and Equipment

​4.1 Multimeter

​4.2 Breadboard

​4.3 Soldering Iron

​4.4 Oscilloscope

​4.5 DC Power Supply

​​4.5.1 Cell and Battery

​​4.5.2 AC/DC Adapters

​Multiple Choice Questions and Answers

Chapter 5. Understanding Circuit/Schematic Diagrams

​5.1 Name Designators and Values

​5.2 Names and Values

​5.3 Circuit Diagram Connections

​5.4 Example Circuit Diagram

​5.5 Some of Circuit Diagram Rules

Chapter 6. Understanding Breadboard

​6.1 Why to Build on a Breadboard?

​6.2 Breadboard Structure

​6.3 Types of Breadboard Connecting Wires

​6.4 Breadboard Power Supply

​6.5 Placing Components on a Breadboard

Chapter 7. Build a Practice Circuit on a Breadboard

​7.1 Reading the Circuit Diagram

​7.2 Building the Circuit

Chapter 8. DIY Electronic Projects

LED Projects

​8.1 Power up Two LEDs Project

​​8.1.1 Schematic Diagram of Power-up Two LEDs Project

​​8.1.2 Parts List

​​8.1.3 Pin Configurations

​​8.1.4 Breadboard Wiring Diagram of Power-up Two LEDs Project

​8.2 Simple Water Level Indicator Project

​​8.2.1 Schematic Diagram of Simple Water Level Indicator Project

​​8.2.2 Parts List

​​8.2.3 Pin Configurations

​​8.2.4 Breadboard Wiring Diagram of Simple Water Level Indicator Project

Transistor Project

​8.3 Make Transistor as a Switch Project

​​8.3.1 Schematic Diagram of Make Transistor as a Switch Project

​​8.3.2 Parts List

​​8.3.3 Pin Configurations

​​8.3.4 Breadboard Wiring Diagram of Make Transistor as a Switch Project

Sensor Projects

​8.4 Build a Light Sensor Project

​​8.4.1 Schematic Diagram of Light Sensor Project

​​8.4.2 Parts List

​​8.4.3 Pin Configurations

​​8.4.4 Breadboard Wiring Diagram of Light Sensor Project

​8.5 Build a Temperature Sensor Project

​​8.5.1 Schematic Diagram of Temperature Sensor Project

​​8.5.2 Parts List

​​8.5.3 Pin Configurations

​​8.5.4 Breadboard Wiring Diagram of Temperature Sensor Project

​8.6 Build a Sound Sensor Project

​​8.6.1 Schematic Diagram of Sound Sensor Project

​​8.6.2 Parts List

​​8.6.3 Pin Configurations

​​8.6.4 Breadboard Wiring Diagram of Sound Sensor Project

DC Motor Project

​8.7 Build a DC Motor Speed Control Project

​​8.7.1 Schematic Diagram of DC Motor Speed Control Project

​​8.7.2 Parts List

​​8.7.3 Pin Configurations

​​8.7.4 Breadboard Wiring Diagram of DC Motor Speed Control Project

Alarm Project

​8.8 Musical Alarm Using IC UM66/BT66 Project

​​8.8.1 Schematic Diagram of Musical Alarm Using IC UM66/BT66 Project

​​8.8.2 Parts List

​​8.8.3 Pin Configurations

​​8.8.4 Breadboard Wiring Diagram of Musical Alarm Using IC UM66/BT66 Project

Ohm’s Law Experiment

​8.9 Verification of Ohm’s Law

​​8.9.1 Schematic Diagram of Ohm’s Law Experiment

​​8.9.2 Pictorial Diagram of Ohm’s Law Experiment

​​8.9.3 Parts List

​​8.9.4 Pin Configurations

​​8.9.5 Procedure

​​8.9.6 Observation Table

Chapter 9. Troubleshooting and Maintenance

​9.1 Basic Troubleshooting Techniques

​9.2 Safety Precautions

​9.3 Maintenance Tips

​Multiple Choice Questions and Answers

Chapter 10. Advanced Electronics

​10.1 Microcontroller a tiny computer

​10.2 Robotics

​10.3 Internet of Things (IoT)

​10.4 Artificial Intelligence (AI)

​Multiple Choice Questions and Answers

Chapter 11. Standard Value Resistors with Color Code

Chapter 12. Standard Value Capacitors with Code and Value Conversion

Chapter 13. Analog and Digital Electronics

​13.1 Analog Electronics

​13.2 Digital Electronics

​Multiple Choice Questions and Answers

Chapter 14. Measurement Units

​14.1 Resistance Measurement Units

​14.2 Capacitance Measurement Units

​14.3 Inductance Measurement Units

​14.4 Voltage Measurement Units

​14.5 Electric Current Measurement Units

​14.6 Electric Power Measurement Units

​14.7 Frequency Measurement Units

​14.8 Digital Measurement Units

​Multiple Choice Questions and Answers

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About this book

Are you looking for a way to introduce your children to the exciting world of electronics?

Do you wish you had a fun and engaging way to teach them the basics of electronics without overwhelming them with technical jargon?

Are you tired of hearing your kids ask, “What does this do?” or “How does that work?” for electronics?

Let’s get started on this electrifying journey together!

Look no further than “Learn Basic Electronics: A Handbook for Beginners”.

The book is the perfect resource for parents, teachers, and anyone looking to inspire young learners to explore the fascinating world of electronics.

We specifically designed this engaging and interactive book to help young learners develop a solid foundation in the basics of electronics.

Whether your child is an aspiring engineer, scientist, or simply curious about how the world works, this book is the perfect way to introduce them to the basics of electronics in a way that’s both educational and entertaining.

They’ll learn how to think like an engineer, troubleshoot problems, and think creatively to come up with their own unique projects.

With clear and concise explanations, illustrations, this book will help kids and develop a solid understanding of the fundamental principles of electronics including circuits, components, and more.

With the help of questions and answers activities, kids will put their knowledge into practice and build simple projects at home.

Kids will learn how to make an LED blink, create basic circuits with integrated circuit (IC), DC motor, transistors and a variety of sensors not excluding light, sound, and temperature sensors and understand the basics of electronics.

“Learn Basic Electronics: A Handbook for Beginners” is more than just a textbook.

So why wait? Join us on this electrifying adventure and discover the fascinating world of electronics together with your kids!

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Chapter 1

Introduction to Electronics

1.1 What is Electronics?

Electronics is a branch of physics and electrical engineering that deals with the emission, behaviour, and effects of electrons using electronic devices.

Electronics is the study and application of the flow of electrons through a circuit.

It uses active devices to control electron flow by amplification and rectification.

It distinguishes from classical electrical engineering, which only uses passive effects such as resistance, capacitance, and inductance to control electric current flow.

We use the manipulation and control of electronic devices and systems for communication, computation, and signal processing.

It is a very important part of our daily lives, and we use electronics from turning on the automatic lights in our homes to listening to music on our phones.

When we use electronics, we are using devices that can manipulate electricity to do what we want them to do.

Some examples of electronic devices include televisions, computers, and phones.

The sensors in our cars tell us when we need to wear a seatbelt.

Electronic devices work by using “circuits” to control the flow of electricity.

Circuits comprise different components, such as resistor, capacitor, transistor, and integrated circuit (IC), which are connected specifically.

We can change how we connect the circuits to control how electricity flows. Without electronics, many things are impossible.

We couldn’t communicate with each other over long distances, watch movies or play video games, or power the machines that assist us in building and creating things.

1.2 Brief History of Electronics

The history of electronics can trace back to the late 19th century when scientists and inventors began experimenting with electricity and its properties.

Credit goes to J. J. Thomson, a British physicist, for discovering the electron in 1897 through experiments with cathode rays.

They are streams of “negatively” charged particles flowing from the negative electrode (cathode) to the positive electrode (anode) in a vacuum tube.

In 1904, an English physicist named John Ambrose Fleming invented the vacuum tube, which was a significant breakthrough in electronics, enabling the development of radio, television, and other electronic devices.

Lee De Forest, an American inventor, scientist, and engineer who lived from 1873 to 1961, invented the triode in 1906, a three-element vacuum tube capable of amplifying electrical signals.

This invention was a fundamental component of early electronics.

We use the vacuum tube in electronic devices until the 1960s.

The transistor replaced the vacuum tube because of its tendency to generate heat, take up more space, and have a slow start.

The invention of the “Transistor” in 1947 by John Bardeen, Walter Brattain, and William Shockley revolutionized electronics and led to the development of modern electronic devices.

Since then, electronics have made significant advancements, leading to the creation of microprocessors, computers, smartphones, and other digital devices.

1.3 Why is Electronics Important?

Electronics are important for various reasons.

It has played a crucial role in the development of modern technology and has transformed the way we live, work, and communicate.

Electronic devices have made our lives more convenient and efficient, enabling us to perform tasks that were once impossible or time-consuming.

In addition, electronics have contributed to the growth of industries, such as telecommunications, information technology, and medical technology, among others.

It has also made significant contributions to scientific research and exploration, allowing us to study and understand the universe in ways that were once unimaginable.

Electronics will continue to shape our world in the years to come.

Its importance lies in its ability to improve our lives, advance technology, and expand our knowledge and understanding of the universe.

Its importance lies in its ability to improve our lives, advance technology, and expand our knowledge and understanding of the universe.

1.4 Conductors

Conductors are materials that allow electric current to flow through them with ease.

“Free electrons” are tiny particles that are found in certain materials, such as metals.

Free electrons are special because they can move around with freedom within the material. They are almost like playing a game of tag.

Ability to move around makes them important for conducting electricity, which is why materials like copper we use often for wires in electrical circuits.

When we talk about free electrons in conductors, we are talking about these tiny particles that can move around and help electricity flow.

Common examples of conductors include metals such as copper, silver, and aluminum.

We often use these materials in electrical wiring and transmission lines because of their high conductivity.

1.5 Insulators

Insulators are materials that do not allow electric current to flow through them easily.

Unlike conductors, insulators do not have free electrons that can move easily through the material.

Instead, insulators prevent the flow of electric current by trapping electrons within their structure.

Common examples of insulators include rubber, glass, and plastic. These materials are often used to insulate electrical wires and components to prevent electric shock.

Electric Wire

A long and narrow piece of metal covered with a protective layer known as insulation is what an electric wire looks like.

This insulation serves as a safeguard, confining the electricity within the wire and preventing it from escaping elsewhere. Whenever you connect a device such as a lamp or TV to an electrical outlet, the wire serves as a channel for the electricity to flow from the socket to the appliance.

The electricity moves through the wire with an electric current. It is much like water flowing through a hose. Electricity is essential, since it powers our appliances and enables our lights to function.

However, because of its enormous power, it’s crucial to handle electric wires with care and follow the instructions of adults when they advise you not to touch them.

1.6 Components

A component is a device or material that is used in circuits to create, control, or manipulate the functions of the circuit.

There are many types of components, including resistors, capacitors, inductors, diodes, transistors, and integrated circuits (ICs).

Each component serves a specific function in a circuit, and a combination of these components can create complex electronic systems.

1.7 Active and Passive Components

Electronic circuits comprise building blocks known as components. We can classify into two types: Active components and passive components.

Active components are electronic devices that require a power source to operate, such as transistors, diodes, and amplifiers.

These components can amplify or switch electronic signals, as well as generate electronic signals.

In contrast, passive components do not require a power source to function.

They passively resist, store, or release electrical energy and do not actively control the flow of current.

Examples of passive components include resistors, capacitors, and inductors.

Active components act as electronic assistants that can perform various functions, whereas passive components act as electronic obstacles that impede or store energy.

Engineers use both types to design and construct a wide range of electronic devices, including radios, computers, cell phones, and video game consoles.

1.8 Symbols

Symbols allow engineers, technicians, and hobbyists to understand the function and connection of different components in an electronic circuit.

For example, a zigzag line often represents a resistor, while it represents a battery by a series of long and short connect lines, a capacitor represented by two parallel lines.

Example of resistors, capacitors, and a battery symbol shown below.

By using standardized symbols, electronic circuits can communicate and designed more efficiently.

In electronics, a symbol is a visual representation that helps us understand the function and connection of different components in an electronic circuit.

Engineers, technicians, and hobbyists use symbols to simplify circuit diagrams and schematics, making it easier to communicate and design electronic circuits.

Example of a cell, and lamp symbols shown below.

Symbols are an essential part of electronics, and they allow us to create complex circuits that power everything from our phones and computers to our homes and cars.

By learning about symbols and how they use, you can gain a deeper understanding of electronics and the technology that surrounds us every day.

1.9 Circuits

The terms “circuit diagram” and “schematic diagram” are often in use interchangeably in electronics.

A circuit is a path through which electric current can flow.

Circuits comprise electrical and electronic components connect by wires, and they can be open or closed.

Components allow current to flow continuously in a closed circuit, whereas an open circuit creates a gap in the path that prevents the current from flowing.

Electrical circuits can power a wide variety of devices, from simple light bulbs to complex computer systems.

1.9.1 Closed Circuit

A closed circuit refers to a circuit in which the current flows through a complete and unbroken path.

Refer to the diagram below, in a closed circuit, electrical energy can flow from the source 1.5 Volts cell, through the circuit component Lamp which acts as a load, and back to the source again, forming a continuous loop.

Illustration below depicts a closed circuit, shown in pictorial diagram. There is a return path for the electric current to flow, resulting in a complete circuit.

Closed circuits are important because they allow electricity to flow continuously and provide power to devices like lights and motors.

By understanding how closed circuits work, you can build and design your own simple electronic circuits.

Advantages of closed circuits include:

Continuous Current Flow: Electric current can flow continuously through the circuit, allowing the device or system to function as intended.

Control of Current: By closing or opening switches within the circuit, you can control the flow of current and, consequently, the operation of electronic components.

1.9.2 Open Circuit

An open circuit is an incomplete circuit. In an open circuit, break or interruption in the flow of current, which prevents electricity from flowing through the circuit.

This means that the circuit does not function as intended. There are many reasons an open circuit might occur.

If a component or wire disconnected, the circuit will become open, and electric current will not flow through it.

The pictorial diagram below shows an open circuit of a cell and lamp.

Advantages of open circuits include:

Safety: In some situations, intentionally opening a circuit can be a safety measure to prevent excessive current flow or to isolate a malfunctioning component.

Control of Devices: Open circuits can be used in devices such as switches, where breaking the circuit turns off a device.

1.9.3 Load

A load is any component or device that consumes power from a source.

It’s something that uses electricity to do something useful. For example, a light bulb is a load because it converts electrical energy into light energy.

To simplify, consider a load as an object that you can plug into an electrical outlet or connect to a battery in order to operate. Loads include lamp, fans, motors, computers, etc.

Example of a lamp as a load shown in the block diagram below.

It’s important to understand the concept of a load because it affects how much power a source needs to provide.

If the load requires a lot of power, the source needs to supply enough current to meet the demand. If the load requires less power, the source doesn’t need to work hard.

1.10 Schematic Diagram

People in electronics often use the terms “circuit diagram” and “schematic diagram” interchangeably.

Schematics are diagrams that show the connections between electrical components in a circuit.

Schematic diagram has a purpose is to provide a graphical representation of a physical circuit that enables designers, technicians and hobbyists to understand and troubleshoot circuit behaviour.

They can quickly identify the cause of a problem and determine the best way to fix it.

These diagrams use symbols to represent the various components and lines to show how they connected.

We should give each component in the diagram a unique name known as reference designation, such as R1, R2, R3, and commonly used abbreviations, such as LA for lamp, BAT for battery, SW for switches, R for resistors, C for capacitors, and U for integrated circuits.

Example below is a circuit diagram (pictorial diagram of the circuit) and a schematic diagram of a cell and lamp.

In the schematic diagram, two lines drawn between 1.5 Volts cell and lamp represent physical wire connection between actual components after assembly.

Ground symbol is a non-component symbol we use in schematic diagrams. Ground symbol represent a common point of electrical connections for all components and power source in the circuit.

A schematic diagram deliberately omits unimportant details to focus on the most crucial information.

Electronic schematic diagram represents by using standardized symbols, which serves as a blueprint for designing, building, and repairing electronic circuits.

Schematic diagrams offer a clear depiction of the basic functioning of an electronic device or system, focusing on underlying hardware or software.

Schematic diagrams are essential because they provide a clear and concise graphical representation of the circuit’s components and their interconnections.

Multiple Choice Questions and Answers

Chapter 1

Introduction to Electronics

1.1 What is Electronics?

Question 1: What is electronics?

A. The study and application of the flow of water in a system.

B. The manipulation and control of electronic devices and systems for communication, computation, and signal processing.

C. The study of plants and animals.

D. The study of rocks and minerals.

Answer: B. The manipulation and control of electronic devices and systems for communication, computation, and signal processing.

Question 2: What are some examples of electronic devices?

A. Televisions, computers, and phones.

B. Motors and engines.

C. Switchgear and panel board.

D. Electric power Transmission and distribution system.

Answer: A. Televisions, computers, and phones.

Question 3: How do electronic devices work?

A. By using tiny units called “circuits” to control the flow of air pressure.

B. By using tiny units called “circuits” to control the flow of water flow.

C. By using tiny units called “circuits” to control the flow of electricity.

Answer: C. By using tiny units called “circuits” to control the flow of electricity.

Question 4: Why is electronics important?

A. Because it helps us communicate with each other over long distances.

B. Because it allows us to watch movies on TV or play video games.

C. Because it powers automatic machines that assist us in building and creating things.

D. All of the above.

Answer: D. All of the above.

1.2 Brief History of Electronics

Question 1: Who discovered the electron in 1897?

A. John Ambrose Fleming

B. Lee De Forest

C. J. J. Thomson

Answer: C. J. J. Thomson

Question 2: What did John Ambrose Fleming invent in 1904?

A. The transistor.

B. The vacuum tube.

C. The triode.

Answer: B. The vacuum tube.

Question 3: Who invented the triode in 1906?

A. John Ambrose Fleming

B. Lee De Forest

C. J. J. Thomson

Answer: B. Lee De Forest

Question 4: What was the fundamental component of early electronics?

A. The triode.

B. The transistor.

C. The vacuum tube.

Answer: C. The vacuum tube.

Question 5: What replaced the vacuum tube in electronic devices?

A. The microprocessor.

B. The transistor.

C. The computer.

Answer: B. The transistor.

Question 6: Who invented the transistor in 1947?

A. John Ambrose Fleming

B. Lee De Forest

C. John Bardeen, Walter Brattain, and William Shockley.

Answer: C. John Bardeen, Walter Brattain, and William Shockley.

Question 7: What did the invention of the transistor lead to?

A. The creation of microprocessors.

B. The development of modern electronic devices.

C. Both A and B.

Answer: C. Both A and B.

1.3 Why is Electronics Important?

Question 1: Why are electronics important?

A. They are fun to play with

B. They have contributed to the growth of industries, science, and technology.

C. They make our lives more difficult and inefficient.

Answer: B. They have contributed to the growth of industries, science, and technology.

Question 2: How have electronics transformed the way we live?

A. They have made our lives more complicated.

B. They have made our lives more convenient and efficient.

C. They have made it harder for us to communicate with others.

Answer: B. They have made our lives more convenient and efficient.

Question 3: What contributions have electronics made to scientific research?

A. They have made it more difficult to study and understand the universe.

B. They have allowed us to study and understand the universe in ways that were once unimaginable.

C. They have not contributed anything to scientific research.

Answer: B. They have allowed us to study and understand the universe in ways that were once unimaginable.

Question 4: What industries have electronics are more contributed to?

A. The traditional fashion industry.

B. The traditional food industry.

C. Telecommunications, information technology, and medical technology.

Answer: C. Telecommunications, information technology, and medical technology.

Question 5: Will electronics continue to shape our world in the future?

A. No, electronics are becoming less important.

B. Yes, electronics will continue to improve our lives and advance technology.

C. Maybe, it depends on how people use electronics.

Answer: B. Yes, electronics will continue to improve our lives and advance technology.

1.4 Conductors

Question 1: What are conductors?

A. Materials that block electric current.

B. Materials that allow electric current to flow through them easily.

C. Materials that store electric charge

Answer: B. Materials that allow electric current to flow through them easily.

Question 2: What enables conductors to conduct electricity?

A. Protons

B. Neutrons

C. Free electrons

Answer: C. Free electrons

Question 3: Which of the following materials are examples of conductors?

A. Rubber, wood, and plastic.

B. Copper, silver, and aluminum.

C. Glass, ceramic, and paper

Answer: B. Copper, silver, and aluminum.

Question 4: Why are conductors such as copper, silver, and aluminum often used in electrical wiring and transmission lines?

A. Because they are .cheap

B. Because they are colorful.

C. Because of their high conductivity.

Answer: C. Because of their high conductivity.

1.5 Insulators

Question 1: What are insulators?

A. Materials that allow electric current to flow easily through them.

B. Materials that do not allow electric current to flow through them easily.

C. Materials that only allow electric current to flow through them in one direction.

Answer: B. Materials that do not allow electric current to flow through them easily.

Question 2: What is the difference between conductors and insulators?

A. Conductors prevent the flow of electric current by trapping electrons within their structure.

B. Conductors have free electrons that can move easily through the material.

C. Insulators are materials that conduct electricity easily.

Answer: B. Conductors have free electrons that can move easily through the material.

Question 3: How do insulators prevent the flow of electric current?

A. By releasing electrons into the material.

B. By trapping electrons within their structure.

C. By creating a magnetic field that repels electric current.

Answer: B. By trapping electrons within their structure.

Question 4: Which of the following are common examples of insulators?

A. Iron, copper, and aluminum.

B. Rubber, glass, and plastic.

C. Gold, silver, and bronze.

Answer: B. Rubber, glass, and plastic.

Question 5: Why are insulators used to insulate electrical wires and components?

A. To allow electric current to flow easily through the material.

B. To prevent electric shock.

C. To increase the conductivity of the material.

Answer: B. To prevent electric shock.

1.6 Components

Question 1: What is a component?

A. A person who creates electronic devices.

B. A device or material use in electronic circuit.

C. A type of circuit that creates electronic signals.

D. A machine used to produce electrical current.

Answer: B. A device or material use in electronic circuit.

Question 2: Which of the following is NOT a type of component?

A. Capacitor

B. Inductor

C. Cell phone

D. Transistor

Answer: C. Cell phone

Question 3: What is the function of a resistor?

A. To store electrical charge.

B. To amplify electrical signals.

C. To regulate the flow of electrical current.

D. To convert electrical energy into mechanical energy.

Answer: C. To regulate the flow of electrical current.

Question 4: Which component can be used to switch electrical signals on and off?

A. Capacitor

B. Inductor

C. Diode

D. Transistor

Answer: D. Transistor

Question 5: What is the purpose of integrated circuits?

A. To make electronic gadget look cool.

B. To combine multiple components into a single device.

C. To control the flow of electrical current.

D. To store electrical charge.

Answer: B. To combine multiple components into a single device.

1.7 Active and Passive Components

Question 1: What are electronic components?

A. Building blocks of electronic circuits.

B. Devices that stores energy to operate.

C. Devices that do not require a power source to function.

Answer: A. Building blocks of electronic circuits.

Question 2: What are active components?

A. Electronic components that require a power source to operate.

B. Electric devices that do not require a power source to function.

C. Electronic devices that impede or store energy.

Answer: A. Electronic components that require a power source to operate.

Question 3: Which of the following are examples of active components?

A. Resistors, capacitors, and inductors.

B. Transistors, diodes, and amplifiers.

C. Radios, computers, and cell phones.

Answer: B. Transistors, diodes, and amplifiers.

Question 4: What functions can active components perform?

A. Passively resist, store, or release electrical energy.

B. Actively control the flow of current.

C. Impede or store energy.

Answer: B. Actively control the flow of current.

Question 5: What are passive components?

A. They require a power source to operate.

B. They do not require a power source to function.

C. Two types of passive components exists, some require a power source and some are not.

Answer: B. They do not require a power source to function.

Question 6: Which of the following are examples of passive components?

A. Transistors and diodes.

B. Resistors, capacitors, and inductors.

C. Vacuum tubes and Integrated Circuits.

Answer: B. Resistors, capacitors, and inductors.

Question 7: What is the function of passive components?

A. To actively control the flow of current.

B. To impede or store energy.

C. To amplify or switch electronic signals.

Answer: B. To impede or store energy.

Question 8: Why do engineers use both types of components?

A. To design and construct a wide range of electronic devices.

B. Only to impede the flow of current in electronic devices.

C. Only to actively control the flow of current in electronic devices.

Answer: A. To design and construct a wide range of electronic devices.

1.8 Symbols

Question 1: What is the purpose of using symbols in electronic circuits?

A. To make the circuit diagrams and schematics look nicer.

B. To make the circuit diagrams and schematics easier to understand.

C. To make the electronic circuits work faster.

Answer: B. To make the circuit diagrams and schematics easier to understand.

Question 2: What does a zigzag line often represent in an electronic circuit?

A. A battery

B. A resistor

C. A capacitor

Answer: B. A resistor

Question 3: How do standardized symbols help in designing electronic circuits?

A. They make the circuits look more complex.

B. They make the circuits communicate better.

C. They condense the circuits to look simple.

Answer: B. They make the circuits communicate better.

Question 4: What does two parallel lines often represent in an electronic circuit?

A. A resistor

B. A transistor

C. A capacitor

Answer: C. A capacitor

Question 5: Why are symbols important in electronics?

A. They make the circuits look pretty.

B. They allow for the creation of complex circuits.

C. They make the circuits look colorful.

Answer: B. They allow for the creation of complex circuits.

Question 6: Who uses symbols in electronic circuits?

A. Only engineers.

B. Only technicians.

C. Engineers, technicians, and hobbyists.

Answer: C. Engineers, technicians, and hobbyists.

Question 7: What can you gain by learning about symbols in electronics?

A. A deeper understanding of electronics and technology.

B. The ability to make condense circuits without any help.

C. The ability to print on paper easily.

Answer: A. A deeper understanding of electronics and technology.

1.9 Circuit

Question 1: What is an electrical circuit?

A. A path for electric current to flow through liquids.

B. A path for electric current to flow through conductors.

C. A path for electric current to flow through air.

Answer: B. A path for electric current to flow through conductors.

Question 2: What are electronic circuits made of?

A. Electrical and electronic components and wires.

B. Only electrical components.

C. Only wires.

Answer: A. Electrical and electronic components and wires.

Question 3: What can electrical circuits power?

A. Only simple light bulbs.

B. Only complex computer systems.

C. A wide variety of devices, from simple light bulbs to complex computer systems.

Answer: C. A wide variety of devices, from simple light bulbs to complex computer systems.

1.9.1 Closed Circuit

Question 1: What is a closed circuit?

A. A circuit that doesn’t work.

B. A circuit where electricity can flow in a complete loop.

C. A circuit that only works with one component.

D. A circuit that only works with two components.

Answer: B. A circuit where electricity can flow in a complete loop.

Question 2: What do components in a closed circuit allow?

A. They allow current to flow continuously.

B. They create a gap in the path, preventing current flow.

C. They make the circuit unstable.

Answer: A. They allow current to flow continuously.

Question 3: What are the three components required to create a functional closed circuit?

A. A light bulb, a motor, and a resistor.

B. A power source, wires, and a load.

C. A switch, a capacitor, and a wire.

D. A resistor, a capacitor, and an inductor.

Answer: B. A power source, wires, and a load.

Question 4: What is a load in a closed circuit?

A. The power source.

B. The wires.

C. A device that uses electricity.

D. A device that generates electricity.

Answer: C. A device that uses electricity.

Question 5: Why are closed circuits important?

A. They allow electricity to flow only in one direction.

B. They create dead ends in the circuit.

C. They allow electricity to flow continuously and provide power to devices.

D. They make electronic devices and gadgets more expensive.

Answer: C. They allow electricity to flow continuously and provide power to devices.

Question 6: What can you do by understanding how closed circuits work?

A. You can make electronic devices and gadgets more expensive.

B. You can break electronic devices and gadgets.

C. You can build and design your own electronic devices and gadgets.

D. You can only study closed loop circuits in theory.

Answer: C. You can build and design your own electronic devices and gadgets.

1.9.2 Open Circuit

Question 1: What is an open circuit?

A. A circuit that allows current to flow continuously.

B. A circuit that creates a gap in the path, preventing current flow.

C. A circuit works only in open space.

Answer: B. A circuit that creates a gap in the path, preventing current flow.

Question 2: What happens in an open circuit?

A. Current flows continuously.

B. Current completes the loop.

C. Current cannot complete the loop.

D. Current flows backward.

Answer: C. Current cannot complete the loop

Question 3: How can open circuits be used in devices such as switches?

A. By completing the circuit.

B. By turning off the device.

C. By increasing current flow.

D. By isolating malfunctioning components.

Answer: B. By turning off the device

Question 4: What is the advantage of using open circuits over closed circuits?

A. Safety and control of devices.

B. B. Continuous current flow.

C. Predictable operation.

D. Controlled current intensity.

Answer: A. Safety and control of devices.

1.9.3 Load

Question 1: What is a load?

A. An object that converts electrical energy into light energy.

B. An object that consumes power from a source.

C. An object that produces electricity.

D. An object that requires a battery to operate.

Answer: B. An object that consumes power from a source.

Question 2: Why is it important to understand the concept of a load?

A. It affects how much power a source needs to provide.

B. It determines the color of the object.

C. It affects the size of the object.

D. It determines the temperature of the object.

Answer: A. It affects how much power a source needs to provide.

Question 3: What happens if the load requires a lot of power?

A. The source doesn’t need to work hard.

B. The source needs to supply enough current to meet the demand.

C. The load just works fine with available power from the source.

D. The source just works fine by supplying whatever power it has.

Answer: B. The source needs to supply enough current to meet the demand.

Question 4: Which of the following is not an example of a load?

A. A light bulb

B. A computer

C. A phone

D. A wall outlet

Answer: D. A wall outlet

1.10 Schematic Diagram

Question 1: What are electronic schematics?

A. Drawings that compare symbols and pictures of components.

B. Diagrams that show the connections between electronic components in a circuit.

C. Pictures of electronic components.

Answer: B. Diagrams that show the connections between electronic components in a circuit.

Question 2: How do schematics show the connections between electrical components?

A. By using words to describe them.

B. By using symbols to represent the various components and lines to show how they connected.

C. By showing pictures of the components.

Answer: B. By using symbols to represent the various components and lines to show how they connected.

Question 3: What are schematics used for?

A. To design and analyze circuits.

B. To learn how to use a gadget.

C. To play electronic video games in proper way.

Answer: A. To design and analyze circuits.

Question 4: Why are schematics essential for troubleshooting problems in electrical systems?

A. Because they look cool.

B. Because they look beautiful.

C. Because by using schematics, engineers and technicians can quickly identify the cause of a problem and determine the best way to fix it.

Answer: C. Because by using schematics, engineers and technicians can quickly identify the cause of a problem and determine the best way to fix it.

Chapter 2

Basic Concepts in Electronics

2.1 Electricity

Electricity is a type of energy that we used to power things like lights, televisions, and computers.

It comes from tiny particles called electrons, which are found in atoms. When electrons move around, they create a flow of electricity.

There are two types of electricity:

Static electricity: This is the type of electricity that we feel when we get a shock after walking across a carpeted floor or rubbing a balloon on our hair.

Two objects rubbing against each other can create static electricity by transferring electrons from one object to another, which results in one object having a positive charge and the other having a negative charge.

When these charges build up, they can create a spark or shock.

Current electricity: This is the type of electricity that powers our homes and electronics.

It is called “current” because the electrons flow in a continuous loop, or current.

We burn coal in coal power plants, creating nuclear fission of radioactive atoms in nuclear power plants to generate electricity.

After that, we send this electricity through wires to our homes and buildings.

We also use natural energy sources such as waterfalls, sunlight, wind, tides and waves of the ocean and sea to generate electricity.

For example, we build solar plants using solar panels, windmill plants using giant fans, geothermal energy using heat energy beneath the earth, and wave energy of ocean and sea surface to generate electricity that we can use.

We can also get current electricity using cell and batteries.

2.2 Electric Power Source

An electric power source is a device that provides electrical energy to power electrical and electronic devices.

In simpler terms, it’s what gives power to electrical and electronic devices like domestic appliances, industrial machines, light, phones, computers, and video games.

An electric power source can come in many forms, such as a battery, a wall outlet, or even a solar panel.

2.3 AC Power Source

An AC power source is a type of electric power source that provides alternating current (AC) electricity to power electronic devices.

AC power is the type of electricity that comes out of wall outlets in most homes and buildings.

AC power differs from direct current (DC) power, which is the type of electricity that batteries provide.

AC power sources typically have a plug we can insert into an outlet to provide power to electronic devices.

Some common examples of electronic devices that use AC power include televisions, refrigerators, and air conditioners.

AC Waveform

An AC waveform refers to the pattern of alternating current flow in an AC power source.

AC, or alternating current, periodically reverses direction, meaning the current flow changes from positive to negative and back again in a regular pattern.

This is in contrast to DC (Direct Current), which flows in only one direction.

We represent the AC waveform on a graph as a sine wave.

A mathematical function known as a sine function can describe the current flow of an AC power source.

The height of the sine wave represents the amplitude of the AC voltage, which is the maximum voltage reached during each cycle of the wave.

The time it takes for one complete cycle of the wave, known as the period and measured in seconds.

The frequency of the AC power source refers to the number of complete cycles that occur in one second. We measure frequency in Hertz (Hz).

In North America and some other regions, the standard AC power source frequency is 60 Hz, meaning that the AC waveform completes 60 cycles per second.

It means AC power source from the wall outlet is 120 Volts/60Hz.

In many Asian, African, and in European countries, standard AC power source frequency is 50Hz, meaning that the AC waveform completes 50 cycles per second.

It means AC power source from wall outlet is 220 or 240 Volts (depends on the country) with 50Hz frequency. If the AC system has a frequency of 60Hz, it means that the current alternates direction back and forth 60 times every second.

By using transformers, the voltage of the AC power source we can increase or decrease, which is necessary for transmitting power over long distances.

Many electrical devices work with AC power sources, and we must carefully regulate the AC waveform to ensure the proper functioning of these devices.

It’s important to use the correct type of power source for your electronic device, as using the wrong type can damage the device or cause it to malfunction.

2.4 DC Power Source

A DC power source is a type of electric power source that provides direct current (DC) electricity to power electronic devices.

Unlike AC power, which alternates in direction, DC power flows in only one direction from negative to positive.

DC power sources can come in many forms, including batteries and power supplies.

Batteries are a common type of DC power source that can power a wide range of electronic devices, such as flashlights, remote controls, and toys.

Power supplies are another type of DC power source that can power electronic devices, such as computers and televisions.

It’s important to use the correct type of power source for your electronic device, as using the wrong type can damage the device or cause it to malfunction.

When selecting a DC power source, it’s important to consider factors such as voltage and current requirements, as well as the type of connector needed to connect the power source to the electronic device.

2.5 Volt and Voltage

“Volt” and “voltage” are both related terms that are often used interchangeably, but they have slightly different meanings.

A volt is a unit of measurement used to describe the amount of electrical potential or electromotive force (EMF) that exists between two points in an electrical circuit.

We named volt after Italian physicist Alessandro Volta, who invented the first battery.

Voltage refers to the measure of the potential difference or electromotive force (EMF) that exists between two points in an electrical circuit.

Consider a water tank at a certain height above the ground. A hose is at the bottom of the tank.

The water pressure represents voltage at the end of the hose.

We often refer it to as electric potential.

An electric charge flows from the point with higher voltage to the point with lower voltage when there is a voltage difference between two points in a circuit.

In simpler terms, voltage is the measure of the electrical pressure that drives the flow of electrical current through a circuit.

The unit used to measure voltage is called a volt.

So while volts are a unit of measurement, voltage is a more general term used to describe the electrical potential difference between two points.

2.6 Electric Current

Electric current is the flow of tiny particles called electrons through a material like a metal wire.

It’s like water flowing through a pipe, but instead of water, its electricity flowing through a wire.

Just like water flows through a pipe when you turn on a faucet, electricity flows through a wire when you turn on a switch.

The unit used to measure current is called an ampere, or “amp” for short.

2.7 Resistance

Resisting or opposing the flow of electricity is a measure of resistance.

We measure the opposition to the flow of electric current in ohms.

Imagine a pipe with water flowing through it. If the pipe is wide and smooth, the water flows easily, but if it is narrow and rough, the water encounters more resistance while flowing through.

Together, voltage, current, and resistance make up the fundamental building blocks of electrical circuits.

2.8 Power

In electronics, “power” refers to the amount of energy transferred or consumed per unit of time in an electrical circuit.

It is a fundamental concept that plays a crucial role in the design, analysis, and operation of electronic systems.

The unit of power is the watt (W), which is equal to one joule per second.

We can calculate power using the formula P = VI,

Where,

P is the power,

V is the voltage,

I is the current flowing through the circuit.

We can also express power in terms of resistance (R) and current (I) using the formula

P = I^2R or P = V^2/R

Understanding the concept of power is essential in determining the efficiency and performance of electronic devices and circuits.

2.9 Series and Parallel Circuits

We can connect electrical circuits in two ways: series and parallel.

In a series circuit, the components are connect end-to-end, creating a single path for the current to flow through.

In contrast, in a parallel circuit, we connect the components in parallel to each other, creating multiple paths for the current to flow through.

The choice of circuit configuration depends on the specific application and desired outcome.

2.10 Ohm’s Law

“Ohm’s Law” named after the German physicist Georg Simon Ohm, who first stated it in 1827.

Ohm’s Law is a fundamental principle in physics that describes the relationship between the voltage, current, and resistance in an electrical circuit.

It states that the current through a conductor between two points is directly proportional to the voltage across the two points, and inversely proportional to the resistance between them.

Mathematically, Ohm’s Law can be expressed as:

V = IR

Where,

V is the voltage across the conductor.

I is the current flowing through the conductor.

R is the resistance of the conductor.

This equation implies that “if the voltage across a conductor increase, the current flowing through the conductor will increase as well, provided that the resistance of the conductor remains constant”.

Similarly, if the resistance of the conductor increase, the current flowing through it will decrease, provided that the voltage remains constant.

2.11 Example Calculations of Ohm’s Law

Finding resistance (R)

If a circuit has a voltage of 12 volts and a current of 3 amps, what is the resistance?

R = V/I R = 12/3 R = 4 ohms

Therefore, the resistance of the circuit is 4 ohms.

Finding voltage (V)

If a circuit has a resistance of 5 ohms and a current of 2 amps, what is the voltage?

V = IR V = 2 * 5 V = 10 volts

Therefore, the voltage of the circuit is 10 volts.

Finding current (I)

If a circuit has a voltage of 24 volts and a resistance of 8 ohms, what is the current?

I = V/R I = 24/8 I = 3 amps

Therefore, the current flowing through the circuit is 3 amps.

Multiple Choice Questions and Answers

Chapter 2

Basic Concepts in Electronics

2.1 Electricity

Question 1: What is electricity?

A. A type of energy that powers things like lights, televisions, and computers.

B. A type of fluid that is used to power cars and airplanes.

C. A type of gas that is used to power cars and airplanes.

Answer: A. A type of energy that powers things like lights, televisions, and computers.

Question 2: In a conductor, what is responsible for the flow of electric current?

A. Photons

B. Electrons

C. Protons

D. Neutrons

Answer: B. Electrons

Question 3: Where do electrons come from?

A. They come from protons.

B. They are found in atoms.

C. They come from outside into the atom.

Answer: B. They are found in atoms.

Question 4: How is static electricity created?

A. By generating electricity in power plants.

B. By rubbing two objects against each other and transferring electrons.

C. By using batteries.

Answer: B. By rubbing two objects against each other and transferring electrons.

Question 5: What is the difference between static electricity and current electricity?

A. Static electricity is created by power plants, while current electricity is created by rubbing two objects against each other.

B. Static electricity results in a spark or shock, while current electricity flows in a continuous loop.

C. Static electricity flows in a continuous loop, while current electricity results in a spark or shock.

Answer: B. Static electricity results in a spark or shock, while current electricity flows in a continuous loop.

Question 6: How is current electricity created?

A. By magnetic fields

B. By static electricity

C. By the flow of electric charge

D. By gravitational force

Answer: C. By the flow of electric charge

2.3 AC Power Source

Question 1: What is an AC power source?

A. A type of electricity that comes from batteries.

B. A type of electric power source that provides alternating current electricity.

C. A device that powers electronic devices with direct current electricity.

Answer: B. A type of electric power source that provides alternating current electricity.

Question 2: What type of electricity do wall outlets in most homes and buildings provide?

A. AC power

B. DC power

C. Both AC and DC power

Answer: A. AC power

Question 3: What is the difference between AC power and DC power?

A. AC power is stronger than DC power.

B. AC power is the type of electricity that comes from batteries, while DC power comes from wall outlets.

C. AC power provides alternating current, while DC power provides direct current.

Answer: C. AC power provides alternating current, while DC power provides direct current.

Question 4: What happens if you use the wrong type of power source for your electronic device?

A. Nothing will happen.

B. The device will work better.

C. The device may get damaged or malfunction.

Answer: C. The device may get damaged or malfunction.

Question 5: Give an example of an electronic device that uses AC power.

A. A battery powered flashlight.

B. A television.

C. A battery powered electric car.

Answer: B. A television.

2.4 DC Power Source

Question 1: What is a DC power source?

A. A source of alternating current electricity.

B. A source of direct current electricity.

C. A source of both alternating and direct current electricity.

Answer: B. A source of direct current electricity.

Question 2: What is the difference between AC and DC power?

A. AC power flows in only one direction, while DC power alternates in direction.

B. AC power alternates in direction, while DC power flows in only one direction.

C. AC and DC power both flow in only one direction.

Answer: B. AC power alternates in direction, while DC power flows in only one direction.

Question 3: What are some examples of electronic devices that can be powered by batteries?

A. Desktop computers and televisions.

B. Portable Flashlights and TV remote controls.

C. Both A and B.

Answer: B. Portable flashlights and TV remote controls.

Question 4: What is the importance of using the correct type of power source for an electronic device?

A. Otherwise it can cause the device to malfunction.

B. Otherwise it can damage the device.

C. Both A and B.

Answer: C. Both A and B.

Question 5: What factors should be considered when selecting a DC power source?

A. Voltage and current requirements.

B. Type of connector needed.

C. Both A and B

Answer: C. Both A and B

2.5 Volt and Voltage

Question 1: What is a volt?

A. A type of battery.

B. A unit of measurement used to describe electrical potential or electromotive force.

C. A measure of the electrical pressure that drives the flow of electrical current through a circuit.

D. Name of an Italian physicist who invented electricity.

Answer: B. A unit of measurement used to describe electrical potential or electromotive force.

Question 2: Who was Alessandro Volta?

A. An Italian physicist who invented electricity.

B. A unit of measurement used to describe electrical potential or electromotive force.

C. A type of battery.

D. A measure of the electrical pressure that drives the flow of electrical current through a circuit.

Answer: A. An Italian physicist who invented electricity.

Question 3: What is voltage?

A. The unit used to measure electrical potential or electromotive force.

B. A type of battery.

C. A measure of the electrical pressure that drives the flow of electrical current through a circuit.

D. The unit used to measure electric current potential force.

Answer: C. A measure of the electrical pressure that drives the flow of electrical current through a circuit.

Question 4: What is the difference between a volt and voltage?

A. There is no difference.

B. The volt is the unit of measurement for electric potential difference, voltage is the electric potential difference between two points in a circuit.

C. A volt is a type of battery, while voltage is a unit of measurement.

D. Voltage is the same as an electric potential, while a volt refers to the potential difference or electromotive force

Answer: B. The volt is the unit of measurement for electric potential difference, voltage is the electric potential difference between two points in a circuit.

Question 5: What flows from the point with higher voltage to the point with lower voltage?

A. Electric charge

B. Electromotive force

C. Electrical potential

D. Magnetic potential

Answer: A. Electric charge

2.6 Electric Current

Question 1: What is electric current?

A. The flow of protons through a conductor.

B. The flow of tiny particles called electrons through a material like a metal wire.

C. The flow of neutrons through a conductor

Answer: B. The flow of tiny particles called electrons through a material like a metal wire.

Question 2: How is electric current similar to water flowing through a pipe?

A. Both flow in a circular motion.

B. Both are solid materials.

C. Both flow through a channel.

Answer: C. Both flow through a channel.

Question 3: What happens when you turn on a switch?

A. Protons starts flowing through a wire.

B. Electricity starts flowing through a wire.

C. Neutrons starts flowing through a wire.

Answer: B. Electricity starts flowing through a wire.

Question 4: How is electric current measured?

A. In ohms

B. In volts

C. In amperes

Answer: C. In amperes

Question 5: What is the unit used to measure electric current?

A. Volt

B. Ampere

C. Ohm

Answer: B. Ampere

2.7 Resistance

Question 1: What is resistance?

A. It is the measure of the flow of electricity.

B. It is the opposition to the flow of electric current.

C. It is the speed of electric current.

Answer: B. It is the opposition to the flow of electric current.

Question 2: How do we measure resistance?

A. In watts.

B. In volts.

C. In ohms.

Answer: C. In ohms.

Question 3: Imagine a pipe with water flowing through it. How does the water flow if the pipe is wide and smooth?

A. The water flows easily.

B. The water encounters more resistance while flowing through.

C. The water flows slowly.

Answer: A. The water flows easily.

Question 4: How does the water flow through a narrow and rough pipe?

A. The water flows easily.

B. The water encounters more resistance while flowing through.

C. The water flows slowly.

Answer: B. The water encounters more resistance while flowing through.

Question 5: What are the fundamental building blocks of electrical circuits?

A. Voltage, power, and speed.

B. Current, resistance, and velocity.

C. Voltage, current, and resistance.

Answer: C. Voltage, current, and resistance.

2.8 Power

Question 1: What does “power” mean in electronics?

A. The amount of energy transferred or consumed per unit of time in an electrical circuit.

B. The ability to lift heavy objects.

C. The speed of an electronic device.

D. The size of an electronic device.

Answer: A. The amount of energy transferred or consumed per unit of time in an electrical circuit.

Question 2: What is the unit of power in electronics?

A. Volt (V)

B. Ampere (A)

C. Watt (W)

D. Ohm (Ω)

Answer: C. Watt (W)

Question 3: What is the formula to calculate power?

A. P = VI

B. P = IR

C. P = V/R

D. P = I/V

Answer: A. P = VI

Question 4: How can we express power in terms of resistance (R) and current (I)?

A. P = IR

B. P = V/R

C. P = I^2R

D. P = V^2/R

Answer: C. P = I^2R

Question 5: Why is understanding the concept of power important in electronics?

A. To find defects in electronic devices.

B. To determine the inefficiency of electronic devices.

C. To determine the efficiency and performance of electronic devices and circuits.

D. To determine the weight of electronic devices.

Answer: C. To determine the efficiency and performance of electronic devices and circuits.

2.9 Series and Parallel Circuits

Question 1: Basically how many ways can we connect electrical circuits?

A. One way

B. Two ways

C. Three ways

D. Four ways

Answer: B. Two ways

Question 2: In which circuit configuration are the components connected end-to-end?

A. Parallel circuit

B. Series circuit

C. Both circuits

D. None of the above

Answer: B. Series circuit

Question 3: In which circuit configuration are multiple paths created for the current to flow through?

A. Parallel circuit

B. Series circuit

C. Both circuits

D. None of the above

Answer: A. Parallel circuit

Question 4: Which circuit configuration should be chosen for a specific application and desired outcome?

A. Only series circuit

B. Only parallel circuit

C. Two circuits in series

D. None of the above (The choice of circuit configuration depends on the specific application and desired outcome).

Answer: D. None of the above (The choice of circuit configuration depends on the specific application and desired outcome).

2.10 Ohm’s Law

Question 1: What is Ohm’s Law?

A. A principle of electrical circuits.

B. A principle of magnetism.

C. A principle of electromagnetism.

Answer: A. A principle of electrical circuits.

Question 2: What does Ohm’s Law describe?

A. The relationship between voltage, current, and resistance.

B. The relationship between volt, voltage, and current.

C. The relationship between volt, voltage, and resistance.

Answer: A. The relationship between voltage, current, and resistance.

Question 3: What is the mathematical equation that represents Ohm’s Law?

A. I = V

B. I = R

C. I = V/R

Answer: C. I = V/R

Question 4: What is resistance?

A. The flow of electricity through a conductor.

B. The force that drives the flow of electricity.

C. The measure of how difficult it is for electricity to flow through a conductor.

Answer: C. The measure of how difficult it is for electricity to flow through a conductor.

Chapter 3

Basic Components

3.1 Switches

Switches are electronic components that allow us to control the flow of electricity in a circuit.

Consider a switch as a gate that can open or close, allowing or preventing the flow of electricity.

The switch being in the “on” position completes the circuit, allowing electricity to flow.

The switch is in the “off” position. It breaks the circuit, preventing the flow of electricity.

There are different forms and dimensions of switches, but they all operate the same.

While certain switches can operate by pushing a button, others may be more intricate and require you to turn a lever or a knob.

Switches are important because they allow us to control when and how electricity flows through a circuit.

This can be useful in many electronic devices, from simple toys to complex machines.

By understanding how switches work, you can explore the world of electronics and begin building your own circuits and devices!

3.1.1 SPST Switch

An SPST switch is a type of switch commonly used in electronics.

SPST stands for Single-Pole-Single-Throw. The above image shows toggle type SPST switch.

A Single-Throw switch, also known as a switch with a single input or “pole,” has two positions: “on” and “off.”

When the switch is on, electricity flows through the circuit.

When the switch is in the “off” position, it disrupts the electricity’s flow.

Think of the door as an analogy; it can either be open, allowing passage through it, or closed, blocking any entry.

SPST switches are often used to turn devices on or off, such as lights, motors, or other electronic components.

We can find them in a variety of devices, from simple toys to complex electronics.

An SPST switch can turn on or off electronic devices.

3.1.2 SPDT Switch

A switch that can control the flow of electricity is called a SPDT switch.

SPDT stands for Single-Pole-Double-Throw, which refers to the way the switch wired. The above image shows toggle type SPDT switch.

To understand what this means, imagine a simple circuit with a battery, a light bulb, and a switch.

The battery provides the power, the light bulb is the device that needs power to light up, and the switch controls whether the electricity flows to the bulb.

A switch with SPDT terminals has three terminals that can connect or disconnect an electrical circuit.

It’s a type of switch that has three metal pieces (terminals) that stick out of it. You can connect wires or other parts of a circuit to these terminals.

The “Single-Pole” part means that the switch has just one input, or source, of electrical power. The “Double-Throw” part means that it can connect or disconnect that power to one of the two different outputs.

Depending on the position of the switch, that connects to either input or output.

When the switch is in one position, it connected the input to the third terminal; when it’s in the other position, it connected the output to the third terminal.

So, in our simple circuit, when the switch is in one position, the circuit is “open” and the light bulb doesn’t receive any power, so it stays off.

The circuit becomes “closed” and allows electricity to flow from the battery through the switch to the light bulb, lighting it up when the switch flips to the other position.

3.1.3 DPDT Switch

A DPDT switch is a type of switch used in electronic circuits that can change the direction of the current flowing through it.

The letters DPDT stand for Double-Pole Double-Throw, so the switch has two independent sets of contacts, each with two positions. The above image shows toggle type DPDT switch.

A railway switch that changes the direction of a train and moves both sets of contacts simultaneously is called a DPDT switch.

When the switch is in one position, the train goes in one direction, and when it’s in the other position, the train goes in the opposite direction.

In electronics, a DPDT switch is commonly used to reverse the direction of a motor or to switch between two different circuits.

If you need to spin two motors in opposite directions with your robot, you can reverse their direction by using a DPDT switch.

3.1.4 Slide Switch

A slide switch is a simple type of switch commonly used in electronic devices to turn them on and off.

A small plastic or metal lever slides back and forth between two positions to control the device.

One position turns the device on, allowing electricity to flow through it and enabling it to function as intended.

Conversely, when the lever is in the “off” position, the circuit brakes and electricity cannot flow, causing the device to turn off.

We often use slide switches in small electronic devices like flashlights, radios, and toys, as they are compact, easy to use, and inexpensive.

We also use them in DIY electronics projects for you, as they are a simple way to turn circuits on and off.

3.1.5 Momentary Push ON Switch

A “Momentary Push ON switch” is common in use in electronic circuits to turn on or off a particular component or function.

As the name suggests, this switch requires a momentary push or press to turn on, and then it automatically turns off when the pressure released. The above image shows tactile type momentary push ON switch.

We can use a momentary push on switch in a doorbell.

When you press the button to ring the doorbell, you are actually pressing a momentary push to ON the switch that completes a circuit, allowing electricity to flow through the doorbell and ring the bell.

Once you release the button, the switch automatically turns off, breaking the circuit and stopping the bell from ringing.

We also used momentary push on switches in many other electronic devices, such as flashlights, remote controls, and even some computer keyboards.

They are an important component in many circuits, allowing users to control and activate various functions with a simple push or press of a button.

3.2 Resistors

Resistors are electrical components that are used to resist the flow of current in a circuit. They come in a variety of shapes and sizes.

Resistors typically made of a material with high resistance, such as carbon or metal.

It’s like a gatekeeper that controls the amount of electricity that can pass through it.

They are often used to control the amount of current flowing through a component or to limit the amount of current flowing through a circuit.

When the electric current flows through a resistor, it encounters resistance from the resistor. This resistance slows down the flow of current and reduces its strength.

It dissipated some of the electrical energy when the current flows through a Resistor.

Resistors are often used to set the level of a signal, to protect sensitive components from excessive current.

We measure resistance of the resistor in ohms (lower case Omega Ω).

They are often color-coded to help people identify their resistance value.

We use resistors in many electronic devices, such as radios, televisions, and computers. We use them in a wide variety of electronic circuits, such as amplifiers, filters, and power supplies.

3.2.1 Fixed Value Resistor

In an electronic circuit, a component called a fixed value resistor limits the amount of current that can flow through it.

A resistor’s resistance, which measures its ability to resist the flow of current, is what we refer to as “fixed value” and we cannot alter.

To grasp this concept more easily, consider electricity as water flowing through a pipe.

Just as pipe can handle a limited amount of water flow at once, a resistor can only handle a specific amount of current flow.

If a resistor experiences an excessive amount of current flow, it may overheat and become damaged. Thus, it is crucial to use the resistor for each job.

Although fixed value resistors vary in size and shape, they all serve the same function of limiting the amount of current in a circuit.

We frequently used these resistors in electronic devices such as radios, televisions, and computers, and are critical components in ensuring that these devices function properly.

3.2.2 Resistor Color Code

The system for identifying the value of a resistor is the color code. This system relies on stripes (bands) of different colors that are painted on the resistor.

Each band corresponds to a different number, and resistors may have 4, 5, or 6 bands on their bodies.

For this discussion, we will focus on 4-band resistors, which are the most commonly used.

In a 4-band resistor, the first two bands show the first two digits of the resistor’s value.

The third band represents the multiplier, which determines the number of zeros that follow the first two digits.

Finally, the fourth band represents the tolerance, showing the allowable deviation of the actual value from the stated value.

Example

A resistor with bands of brown, black, red, and gold is below.

The first band (brown) signifies the number 1, while the second band (black) represents the number 0.

The third band (red) shows the multiplier, which is 100, signifying two zeros following the first two digits.

Therefore, the resistor’s value is 10 x 100 = 1000 ohms. The fourth band (gold) shows the tolerance, which is ± 5%.

Thus, the actual value of the resistor can differ by up to 5% from its stated value of 1000 ohms.

When you look at a resistor’s photo above, some questions that may come to your mind include:

What are those color stripes (color bands) on the resistor?

The purpose of the color stripes?

Why are there different color stripes on resistors?

How many colors on a resistor, and what do they represent?

Why are there different color combinations on different resistors?

Why some color stripes repeat on a resistor?

Answer is,

- The resistor color code is a system used to identify the value of a resistor.

- We measure the amount of resistance of a resistor in ohms (symbol is the upper case omega Ω).

- The color code is based on a series of color bands that are painted onto the body of the resistor.

- Each band represents a different digit or multiplier that helps to determine the resistor’s value.

- The first two bands represent the digits.

3.2.3 Example Calculations of Resistor Color Code

For example, for a resistor with color code brown, black, red and gold, the first band is brown and the second band is black, these two colors represent numbers 1 and 0, it means 10. The third band red represent multiplier, which is 100.

Two ways to find resistor value.

Method 1: Using multiplier or power of 10

Third band represents the multiplier or power of 10 applies to the first two digits.

For example, if the third band is red, the multiplier is 10 power 2 (10x10) that is 100.

10x100 = 1000 ohms

Value of the resistor in this example would be 1000 ohms, or 1 kilo ohm, as shown in the resistor photo below.

Method 2: Replacing third band with number of zeros

The third band is red, which represents number 2. Replace third band with two zeros.

1000 = 1000 ohms

Tolerance Band

The fourth band, if present, represents the tolerance of the resistor.

This shows the amount by which the actual value of the resistor may differ from the stated color code value.

3.2.4 Example Calculations of Tolerance Band

Example 1:

If the fourth band is gold, the tolerance is ±5%, which means the actual value of the resistor could be up to 5% higher (+5%) or lower (-5%) than the stated value.

If a resistor has the colors brown, black, brown, and gold, as shown in the image below,

The value is 100 ohms resistor as given below.

Brown = 1, Black = 0, Brown = 1 (10 power 1, or one zero), with a tolerance of +5% (gold = +5%).

Tolerance +5% means,

Value of resistor anywhere between 100Ω+5% and 100Ω-5%

5% of 100Ω is 5Ω

That is 100Ω+5Ω = 105Ω, and 100Ω-5Ω = 95Ω

The value of resistance when we measure with the measuring instrument, show value anywhere between 95Ω to 105Ω.

Example 2:

If a resistor has the colors red, red, orange, and gold as shown in the image below,

The value of the resistor is 22,000 ohms, as given below.

Red = 2, Red = 2, Orange = 3 (10 power 3 or three zeros), with a tolerance of 5% (gold = 5%).

Show image with arrow marks to tolerance band gold with 5%.

Value of 22,000 ohms resistor. You can also rewrite as 22k ohms.

Tolerance +5% means,

Value of resistor anywhere between 22kΩ+5% and 22kΩ-5%

5% of 22kΩ is 1100Ω (1.1k)

That is 22kΩ+1.1kΩ = 23.1kΩ, and 22kΩ-1.1kΩ = 20.9kΩ

The value of resistance when we measure with the measuring instrument, show value anywhere between 20.9kΩ to 23.1kΩ.

“Kilo is Key,”

If a number on a resistor is followed by the letter “K,” it means “thousand.”

So, 1k means 1,000 ohms,

10k means 10,000 ohms, and so on.

By looking at the color bands on the resistor, you can determine its resistance in ohms.

This helps to ensure that electronic circuits built correctly and work as intended.

Now you know the purpose of a color band on resistors. Some questions may come to your mind as listed below.

What is the sequence of colors?

Which color represents what number?

How do you know what value a resistor has based on the color code?

I noticed in the photo shown below, why are some resistors bigger or smaller than others, even if they have the same color bands?

How do I read the color code on a resistor accurately?

How do I read the color bands to determine the value of the resistor?

How do I know which color band is the first, second, and third one?

How to remember resistor color code?

We give answers in the next sections.

3.2.5 How to Remember Resistor Color Code

Sequence of color and number represent each color is,

Black = 0

Brown = 1

Red = 2

Orange = 3

Yellow = 4

Green = 5

Blue = 6

Violet = 7

Gray = 8

White = 9

The following mnemonic help you remember resistor code and number represent each color easily.

NOTE: Ohm (Ω) replaces with letter E or letter R in some circuits/schematics, books and technical documents.

Example

Two different ways represent the value of electrical resistance of 56 ohms: 56E and 56Ω.

The “E” denotes the metric prefix “ohm” in 56E, commonly used in the electronics industry to show resistor values. Therefore, 56E signifies 56 ohms.

56Ω signifies the same value of resistance but uses the “ohm” symbol (Ω) instead of the “E” notation.

Both notations are interchangeable and common in use.

However, it is crucial to use the notation for the specific application to ensure the correct resistance value use.

Some standard value resistor color codes, value, and tolerance are in the table below.

We frequently use these values with a tolerance of 5%.

3.2.6 Resistors in Series

We use resistors in electronics to limit the flow of electric current.

When multiple resistors connect end-to-end, they said to be “in series.”

Think of a water hose. If you attach a nozzle to the end of the hose, it restricts the flow of water. Similarly, a resistor restricts the flow of the electric current in a circuit.

When resistors connect in series, the total resistance of the circuit is equal to the sum of the individual resistances.

This means that if you have two resistors, one with a resistance of 10 ohms and another with a resistance of 20 ohms, and you connect them in series, the total resistance of the circuit will be 30 ohms (10 ohms + 20 ohms) as shown in the illustration below.

Total resistance R across points A and B = 30 ohms.

Series resistors are useful in electronic circuits, where you can limit the amount of current flowing through a particular part of the circuit.

By adding resistors in series, you can control the total resistance of the circuit and, therefore, control the amount of current flowing through it.

To calculate the total resistance (R) of resistors in series, use the formula.

R = R1 + R2 + R3 +...

“R” stands for the total resistance of the resistors in series, and R1, R2, and R3, etc. stand for the resistance of each individual resistor.

3.2.7 Example Calculations of Resistors in Series

When resistors connect in series, their resistances add together to create a larger overall resistance.

Example 1

Let’s say you have three resistors with the following resistances:

R1 = 100 ohms,

R2 = 200 ohms, and

R3 = 300 ohms.

To find the total resistance of the circuit, you would use the following formula.

Total resistance R = R1 + R2 + R3

Plugging in the values, we get:

Total resistance R = 100 ohms + 200 ohms + 300 ohms

Total resistance R= 600 ohms

So the total resistance of the circuit is 600 ohms.

Example 2

Now let’s say you have four resistors with the following resistances:

R1 = 50 ohms,

R2 = 100 ohms,

R3 = 150 ohms, and

R4 = 200 ohms.

To find the total resistance of the circuit, you would again use the formula.

Total resistance R = R1 + R2 + R3 + R4

Plugging in the values, we get:

Total resistance R = 50 ohms + 100 ohms + 150 ohms + 200 ohms

Total resistance R = 500 ohms

So the total resistance of the circuit is 500 ohms.

By connecting resistors in series, we can effectively increase the overall resistance of a circuit.

This concept is important in many areas of electronics, such as in designing circuits to control the amount of current that flows through them.

3.2.8 Resistors in Parallel

When you add a resistor in parallel to an electronic circuit, you create an additional pathway for electric current to flow.

Unlike connecting resistors in series, where the current must pass through the resistor before moving on to the next component, connecting resistors in parallel is like adding an extra road for the current to travel on.

It can help make the current flow more smooth and protect other components from receiving too much current.

When you connect two or more resistors in parallel, electricity can flow through each resistor separately.

This is different to connecting them in a series, where electricity must flow through each resistor.

The total resistance of resistors connected in parallel is less than the resistance of the smallest individual resistor.

Because electricity has multiple paths to follow, reducing the effort required to pass through the circuit.

This means that if you have two resistors, one with a resistance of 10 ohms and another with a resistance of 20 ohms, and you connect them in parallel, the total resistance of the circuit will be 6.67 ohms (1/10 ohms + 1/20 ohms).

Total resistance R across points A and B = 6.67 ohms.

To calculate the total resistance of resistors in parallel, use the formula:

1/R = 1/R1 + 1/R2 + 1/R3 +...

“1/R” stands for the total resistance of the resistors in parallel, and R1, R2, and R3, etc. stand for the resistance of each individual resistor.

3.2.9 Example Calculation of Resistors in Parallel

Example

Let’s say you have two resistors with resistances of 10 ohms and 20 ohms, and you want to know the total resistance when they’re connect in parallel.

Using the formula above, you would calculate:

1/R = 1/10 + 1/20

1/R = 0.1 + 0.05

1/R = 0.15

1/0.15 = 6.67 ohms

Total resistance R = 6.67 ohms

So the total resistance of the two resistors in parallel is 6.67 ohms.

This is less than the resistance of either of the individual resistors,

3.2.10 Variable Resistor

A variable resistor is an electronic component that can change the amount of electrical current that flows through a circuit.

It works by allowing the user to adjust the amount of resistance in the circuit. A material’s resistance is how much it resists electrical current.

A variable resistor has three terminals, or points of contact.

First and third terminals (A and C) connect to the circuit, the middle terminal (B) is for user to adjust the resistance.

By turning a knob or sliding a lever, the user can change the amount of resistance in the circuit, which affects the amount of electrical current that flows through it.

We use variable resistors in a variety of electronic devices, such as radios, televisions, and dimmer switches for lights.

They allow users to control the amount of electricity flowing through a circuit, which can be helpful for adjusting volume, brightness, or other features.

A potentiometer and a preset are two types of variable resistor used to control the amount of current flowing through a circuit.

They work by changing the amount of resistance in the circuit. Function of both types are same, but how we use is different.

Potentiometer

A potentiometer, also known as a “POT,” is a variable resistor we can adjust to change the resistance in a circuit.

It has three terminals: two fixed resistance terminals, and a wiper terminal.

Turning the shaft of the potentiometer, the position of the wiper terminal changes, which changes the amount of resistance in the circuit.

We commonly use potentiometers in audio equipment to control volume and tone, and in other applications where a variable resistor is in need.

Preset

A preset, also known as a “trimmer potentiometer” or “trim pot,” is a small variable resistor that is used to set a specific resistance value in a circuit.

Unlike a regular potentiometer, presets assembled on the printed circuit board (PCB) can adjust only once during the initial setup of a circuit and then left alone. If the circuit malfunction we can adjust the preset multiple times if required.

Preset has three terminals, two fixed resistance terminals, and a wiper terminal.

By turning a small screw with a screwdriver, we can adjust resistance value to a specific level.

We commonly use presets in electronic devices such as radios and TVs for adjusting the voltage levels and frequencies of the circuit.

3.2.11 Light Dependent Resistor (LDR)

A Light Dependent Resistor (LDR), also known as a photoresistor, is a component that decreases resistance to incoming light on its sensitive surface.

In 1873, English electrical engineer Willoughby Smith discovered that selenium’s electrical resistance changes depending on the amount of light that falls on it, leading to the idea of photo-resistors and the development of many variants in photoconductive devices.

Selenium’s photoconductivity provided a method for converting images into electrical signals, forming the theoretical basis for television and photoelectric cells.

Over time, scientists and engineers have refined and developed the LDR, making it widely used today in a variety of applications.

We compose LDRs of the inorganic compound like cadmium sulfide or lead sulfide categorized as semiconductor n-type, which has a high resistance in the dark and low resistance in the light.

We sandwich the material between two metal contacts.

When light falls on the LDR, its resistance decreases, allowing more current to flow through it.

Conversely, when the light level decreases, the resistance of the LDR increases, limiting the amount of current flowing through it.

We commonly use LDRs in automatic lighting systems where they turn on lights when the ambient light level falls below a certain threshold. Streetlights, cameras, solar cells, and alarms also use LDRs.

This helps save energy by ensuring that lights are only on when needed.

We also used LDRs in solar cells to detect the level of sunlight and adjust the solar cell’s output, maximizing its efficiency and the amount of electricity it can generate.

3.2.12 Thermistor

A thermistor, which is a temperature-sensitive resistor, detects changes in temperature. Its resistance changes when it exposes to heat.

Michael Faraday discovered the first NTC thermistor in 1833 by observing the semiconducting behaviour of silver sulfide.

He noticed a significant decrease in the resistance of silver sulfide as the temperature increased, marking the first documented observation of a semiconducting material.

However, early thermistors were challenging to produce, and they have limited practical applications.

Commercial production of thermistors only started in the 1930s. Samuel Ruben invented a commercially viable thermistor in 1930.

The change in resistance we can measure and used to determine the temperature of the thermistor’s surroundings.

Electronic devices like thermostats use thermistors to control the temperature of a room or building.

Thermistors can also monitor the temperature of components in electronic circuits to prevent overheating.

NTC and PTC Thermistor

Thermistors are resistors that exhibit a change in resistance as the temperature changes. There are two types of thermistors: NTC and PTC.

NTC thermistors show a negative temperature coefficient, resulting in a decrease in resistance as the temperature rises.

We commonly use these thermistors in temperature control and sensing applications, such as in temperature sensors, thermostats, and temperature compensation circuits.

PTC thermistors exhibit a positive temperature coefficient, causing an increase in resistance as the temperature increases.

We use these thermistors in overcurrent protection, inrush current limiting, and self-regulating heating applications, including motor starters, heating elements, and automotive circuits for preventing circuit overloading.

3.3 Capacitors

Capacitors are devices that store electrical energy in an electric field.

The unit of electrical capacitance known as Farad honors the memory of Michael Faraday.

He was a British scientist who made significant contributions to the fields of electromagnetism and electrochemistry during the 19th century.

We measured capacitance in units called Farads (F).

However, most fixed value capacitors have a capacitance between microfarads (µF) or picofarads (pF) or nanofarads (nF).

They comprise two conductive plates separated by a non-conductive material, such as air or plastic.

Applying a voltage across the plates creates an electric field between them, which stores energy.

We commonly use capacitors in electronic circuits to filter out noise, smooth out voltage fluctuations, and to store energy for short periods of time.

There are two types of capacitors: polarized and non-polarized.

Photos of polarized with + and -, and non-polarized

Polarized capacitors have a positive and negative lead, while non-polarized capacitors do not have any polarity and can connect in either direction.

3.3.1 Fixed Value Capacitor

Capacitors are available in various types and sizes, but a fixed value capacitor has a set capacitance, meaning that it can store a specific amount of electrical charge and we cannot change.

We use fixed value capacitors in many electronic devices to perform various functions, such as filtering out unwanted noise, smoothing out voltage fluctuations, and coupling one circuit to another.

For example, in a simple radio circuit, a fixed value capacitor might tune the radio to a specific frequency by storing electrical energy at the desired frequency.

Fixed value capacitors can make from various materials, such as ceramic, tantalum, and aluminum.

We represent capacitor values in picofarads (pF), nanofarads (nF), or microfarads (µF).

We represent the value code in by a three-digit number, where the first two digits represent the significant figures and the third digit represents the multiplier.

For example, a capacitor with a value code of 104 represents a capacitance value of 10, followed by 4 zeros, or 100,000pF (or 0.1µF).

3.3.2 Ceramic Disc Capacitor

This is a non-polarized type capacitor. It is a component used in electronic circuits. It’s a type of capacitor, which is a device that can store electrical energy.

The Ceramic Disc Capacitor comprises two metal plates separated by a ceramic disc.

When electricity flows into the capacitor, it charges up the plates and the ceramic disc stores the electrical energy.

Then, when the electricity flow stops, the capacitor releases the stored energy back into the circuit.

We commonly use ceramic Disc Capacitors in electronics to smooth out power supplies and filter out unwanted electrical signals.

They come in different sizes, and capacitance values, depending on the specific needs of the electronic circuit.

We list some of the common use Ceramic Disc Capacitor codes and the value below.

3.3.3 Capacitor Value Conversion

We measure capacitors in units called “Farads,” but sometimes their values may be too small or too large to function in the correct way in an electronic circuit.

To overcome this issue, one can convert a capacitor’s value from one unit to another.

We measure capacitance in units such as microfarads (μF), picofarads (pF), and nanofarads (nF), besides Farads (F). You can convert capacitor values between nF, pF, and µF units.

1nF (nanofarad) is equal to 1000pF (picofarad) and 0.001µF (microfarad).

3.3.4 Example Calculation to Convert a Value from nF to pF

To convert a value from nF to pF, multiply the value by 1000.

For example, to convert 2nF to pF, multiply 2 by 1000, which gives 2000pF.

Example Calculation

To convert a value from nF (nanofarads) to pF (picofarads), you need to multiply the value in nF by 1000 (the number of picofarads in one nanofarad).

Mathematically, the formula for converting nF to pF is:

pF = nF x 1000

For example, let’s say you have a capacitor with a value of 0.47nF and you want to convert it to pF:

pF = 0.47nF x 1000 = 470pF

So, 0.47nF is equal to 470pF.

3.3.5 Example Calculation to Convert a Value from nF to µF

To convert a value from nF to µF, divide the value by 1000.

For example, to convert 5nF to µF, divide 5 by 1000, which gives 0.005µF.

Example calculation

To convert a value from nF (nanofarads) to µF (microfarads), you need to divide the value in nF by 1000.

The formula for the conversion is:

µF = nF / 1000

For example, if you have a capacitor with a capacitance of 100nF, the equivalent value in µF would be:

µF = 100nF / 1000µF = 0.1µF

Therefore, 100nF is equivalent to 0.1µF.

3.3.6 Example Calculation to Convert a Value from pF to nF

To convert a value from pF to nF, divide the value by 1000.

For example, to convert 500pF to nF, divide 500 by 1000, which gives 0.5nF.

Example calculation

To convert a value from pF (picofarads) to nF (nanofarads), you need to divide the value in pF by 1000.

1nF = 1000pF, so to convert pF to nF, you can use the formula:

nF = pF / 1000

For example, if you have a capacitance value of 470pF, to convert it to nF, you would divide by 1000:

nF = 470pF / 1000 = 0.47 nF

Therefore, 470pF is equivalent to 0.47nF.

3.3.7 Example Calculation to Convert a Value from pF to µF

To convert a value from pF to µF, divide the value by 1,000,000.

For example, to convert 1000pF to µF, divide 1000 by 1,000,000, which gives 0.001µF.

Example calculation

To convert a value from pF (picofarads) to µF (microfarads), you need to divide the value in picofarads by 1,000,000 (which is the same as multiplying by 0.000001). This is because one microfarad is equal to one million picofarads.

For example, if you have a capacitance of 100pF, you can convert it to µF using the following formula:

100pF / 1,000,000 = 0.0001µF

Therefore, 100pF is equal to 0.0001µF.

3.3.8 Example Calculation to Convert a Value from µF to nF

To convert a value from µF to nF, multiply the value by 1000.

For example, to convert 0.02µF to nF, multiply 0.02 by 1000, which gives 20nF.

Example calculation

To convert a value from µF (microfarads) to nF (nanofarads), you need to multiply the value by 1000.

For example, let’s say you have a capacitor with a value of 2µF, and you want to convert it to nF. You would use the following formula:

2µF x 1000 = 2000nF

Therefore, 2µF is equal to 2000nF.

3.3.9 Example Calculation to Convert a Value from µF to pF

To convert a value from µF to pF, multiply the value by 1,000,000.

For example, to convert 0.005µF to pF, multiply 0.005 by 1,000,000, which gives 5000pF.

Example calculation

To convert a value from µF (microfarads) to pF (picofarads), you need to multiply the value in µF by 1,000,000. This is because there are 1,000,000 picofarads in one microfarad.

Therefore, the conversion formula is:

pF = µF x 1,000,000

For example, if you have a capacitance value of 0.01µF and you want to convert it to pF, you can use the formula:

pF = 0.01µF x 1,000,000 = 10,000pF

So, 0.01µF is equivalent to 10,000pF.

3.3.10 Capacitor Conversion Table

3.3.11 Electrolytic Capacitor

An electrolytic capacitor is a polarized type, and it is a type of component that is used in circuits to store electrical energy.

They are often used to smooth out electrical signals, remove noise, and stabilize power supplies.

An electrolytic capacitor differs from other types of capacitors because it uses a special electrolyte to store the electrical charge.

This electrolyte is a liquid or gel that is sandwiched between two metal plates, called electrodes.

While using different metals, we make one electrode out of aluminum. The other electrode is tantalum.

When an electrical current flows through the capacitor, the electrolyte reacts with the metal plates and creates a thin oxide layer.

This layer acts as an insulator, which prevents the capacitor from discharging too quickly.

The larger the surface area of the metal plates, the more charge the capacitor can store.

We commonly use electrolytic capacitors in electronic devices, such as computers, televisions, and radios.

We also use them in power supplies, where they help to filter out noise and provide a stable source of power.

Polarity of an electrolytic capacitor is important because if we connect it to the wrong way, it can damage or even explode.

Ensure that you connect the positive lead to the positive side of the circuit and the negative lead to the negative side of the circuit.

The capacitor manufacturer typically prints a stripe or arrow on one side of the capacitor’s body to show the polarity of its leads, which can be positive or negative.

3.3.12 Capacitors in Series

When we talk about “capacitors in series” in electronics, we are referring to a specific way of connecting multiple capacitors together.

Capacitor can be non-polarized or polarized type.

When we connect multiple capacitors in series, we’re essentially linking them together end-to-end.

Series capacitors create a single chain of capacitors.

The total capacitance value is less than the smallest capacitance value of the individual capacitors.

In electronics, connecting capacitors in series can be useful for a variety of reasons.

For example, it can help you achieve desired total capacitance in a circuit without having to search for a single capacitor whose standard value does not exist.

Ceramic disc capacitors are we can connect in series as shown in the diagram below.

Note that they don’t have polarity, and we can use any of lead/pin for connection.

If you have three ceramic disc capacitors, with a capacitance of 10pF, 20pF and 30pF, and you connect them in series, the total capacitance of the circuit will be 5.45pF.

Total capacitance C across points A and B = 5.45pF.

Electrolytic capacitors we can connect in series, as shown in the diagram below.

Note that they have polarity, and the positive end of one capacitor connects to the negative end of another capacitor.

If you have three 10µF electrolytic capacitors, and you connect them in series, the total capacitance of the circuit will be 3.33µF.

Total capacitance C across points A and B = 3.33µF.

The formula for total Capacitance capacitors in series is:

1/C = 1/C1 + 1/C2 + 1/C3 +...

Where C1, C2, C3... are the individual capacitances of each capacitor in the series.

To find the total capacitance, simply solve for Total Capacitance:

Total Capacitance = 1 / (1/C1 + 1/C2 + 1/C3 + ...)

This formula tells us that the total capacitance of capacitors connect in series is less than any individual capacitance.

This is because it increased the effective distance between the plates of each capacitor when they connect in series, resulting in less charge storage capacity.

3.3.13 Example Calculations of Capacitors in Series

When capacitors connect in series, their capacitances add up, but their equivalent capacitance is always less than the smallest individual capacitance.

Example 1

If you connect a 2pF capacitor and a 4pF capacitor in series, the equivalent capacitance would be:

C = 1 / (1/C1 + 1/C2)

C = 1 / (1/2pF + 1/4pF)

C = 1 / (0.5 + 0.25)

C = 1 / 0.75

C = 1.33pF

Example 2

If you connect a 10µF capacitor and a 100µF capacitor in series, the equivalent capacitance would be:

C = 1 / (1/C1 + 1/C2)

C = 1 / (1/10µF + 1/100µF)

C = 1 / (0.1 + 0.01)

C = 1 / 0.11

C = 9.09µF

Note that in both examples, the equivalent capacitance is less than the smallest individual capacitance (2pF and 10µF, respectively).

3.3.14 Capacitors in Parallel

Putting capacitors in parallel has a few important effects.

First, the total capacitance increases, so the capacitors can hold more charge.

Second, the overall voltage rating of the capacitors remains the same, which means we can use them in higher voltage circuits without being damaged.

When capacitors connect in parallel, the total capacitance of the circuit is equal to the sum of the individual capacitances.

When we connect two or more capacitors in parallel, we link their positive and negative ends, allowing them to share the same voltage.

Ceramic disc capacitors are we can connect in parallel, as shown in the diagram below.

Note that they don’t have polarity, and we can use any of lead/pin for connection.

If you have three ceramic disc capacitors, with a capacitance of 10pF, 20pF and 30pF, and you connect them in parallel, the total capacitance of the circuit is 60pF.

Total capacitance C across points A and B = 60pF.

Electrolytic capacitors we can connect in parallel, as shown in the diagram below.

Note that they have polarity, and the all positive ends connected, and all negative ends connected.

If you have three 10µF electrolytic capacitors, and you connect them in parallel, the total capacitance of the circuit is 30µF.

Total capacitance C across points A and B = 30µF.

To determine the total capacitance of capacitors in parallel, use the following formula to add up the capacitance values of each capacitor in the configuration and the total Capacitance

C = C1 + C2 + C3 +...

Where C1, C2, C3... are the capacitance values of each capacitor.

Capacitance values of capacitors in parallel add up to give the total capacitance of the circuit because the voltage across each capacitor remains the same, and the charge stored in each capacitor is directly proportional to its capacitance.

As a result, the total charge stored in the parallel capacitors equals the sum of the charges stored in each individual capacitor, which is equal to the sum of their capacitance.

3.3.15 Example Calculations of Capacitors in Parallel

Example 1

If you connect two capacitors with capacitance values of 0.47nF and 22nF in parallel, what is the total capacitance?

To find the total capacitance of capacitors connect in parallel, you simply add their individual capacitance values.

C = C1 + C2

C = 0.47nF + 22nF

In this example, the total capacitance is 0.47nF + 22nF = 22.47nF.

Example 2

If you have three capacitors with capacitance values of 5μF, 10μF, and 15μF connect in parallel, what is the total capacitance?

To find the total capacitance of capacitors connect in parallel, you add their individual capacitance values.

C = C1 + C2 + C3

In this example, the total capacitance is 5μF + 10μF + 15μF = 30μF.

3.3.16 Variable Capacitor

A variable capacitor allows the change of its capacitance, which refers to its ability to store an electrical charge.

We can change the capacitance of a variable capacitor by adjusting the distance between two metal plates inside the capacitor.

The closer the plates are, the higher the capacitance. Farther apart they are, the lower the capacitance.

We can adjust this distance using a knob or screw, which changes the position of one plate.

We commonly use variable capacitors in radio tuners, where they help to fine-tune the frequency of the radio signal.

By adjusting the capacitance, the tuner can select a specific frequency and filter out unwanted signals.

We also use them in other electronic circuits where it is necessary to adjust the capacitance, such as in oscillators, filters, and resonant circuits.

So, a variable capacitor is an electronic component that can store electrical energy, and we can adjust its capacitance by changing the distance between two metal plates using a knob or screw.

Tuning Capacitor

The rotor-stator capacitor, also known as a tuning capacitor, is a variable capacitor we can adjust to change the capacitance within a circuit.

This type of capacitor comprises two sets of metallic plates, with one set fixed and the other set attached on a shaft to make the rotor.

To change the capacitance, we turn the shaft, so that the rotor plates mesh with the fixed plates while air acts as a dielectric.

When the plates interlock fully, the effective area is at its largest, resulting in peak capacitance.

When the plates are not meshing, the effective area decreases, resulting in minimal capacitance.

The maximum and minimum limits allow for countless variable capacitances in theory.

Gang Tuning Capacitor

A gang tuning capacitor compose of two or more individual variable capacitors with mechanical link so that we can adjust together with a single control.

The term “gang” refers to the fact that the individual capacitors connect, as if they are part of a gang.

We use ganged tuning capacitors in RF circuits to tune the frequency of a resonant circuit, such as a radio receiver or transmitter.

By adjusting the capacitance of the ganged tuning capacitor, we can change the resonant frequency of the circuit we can change the resonant frequency of the circuit.

We can find gang tuning capacitors in a variety of electronic devices, including radios, televisions, and other electronic equipment that require precise frequency tuning.

Trimmer Capacitor

Unlike fixed capacitors, trimmers assembled on the printed circuit board (PCB) can adjust only once during the initial setup of a circuit and then left alone.

If the circuit malfunction we can adjust the trimmer multiple times if required.

Trimmer capacitor has three terminals, two fixed capacitance terminals, and a wiper terminal. Some manufacturers also make two terminal trimmer capacitors.

By turning a small screw with a screwdriver, we can adjust resistance value to a specific level.

3.4 Inductors

Inductors are devices that store energy in a magnetic field.

They comprise a coil of wire (copper), which creates a magnetic field when current flows through it.

The strength of the magnetic field depends on the number of turns in the coil and also the amount of current flowing through it. Inductance of an inductor increase if the number of turns in the coil is increases.

The American scientist Joseph Henry, who pioneered the construction of strong, practical electromagnets and built one of the first electromagnetic motors, has a unit of inductance named after him, called the Henry (H).

Letter L is reference designation for inductor symbol in schematic diagrams.

We define one henry of inductance as the amount of inductance that an inductor generates when the current passing through it changes at a rate of one ampere per second, inducing an electromotive force of one volt.

We commonly use inductors in electronic circuits to filter out noise, block DC signals, and to store energy.

3.4.1 Fixed Value Inductor

An inductor is a component that stores energy in a magnetic field when an electric current passes through it.

The types of fixed value inductors include air core, iron core, and ferrite core.

The iron and ferrite cores increase the inductor’s magnetic field. Color coded axial lead inductors also available which is suitable for printed circuit board (PCB) mounting.

We use distinct symbols to represent each type. We showed the generic symbol for a fixed value inductor below.

Fixed value inductor has a specific, unchanging value of inductance, which is the measure of how much energy the inductor can store.

Think of a fixed value inductor like a battery that can store electricity.

When you connect the inductor to a circuit, it can store energy in its magnetic field and release it back into the circuit later.

Fixed value inductor is useful in electronic circuits that need to regulate the flow of electricity, filter out noise, or perform other functions.

We refer inductors with a fixed value to as “fixed” because of their unchanging inductance value, in contrast to variable inductors can adjust to alter their inductance value.

Color Code Axial Lead Inductor

Color coded axial inductor has a cylindrical shape and two wires called “leads” that stick out from either end. The leads make easy to connect the inductor to other components in a circuit.

We made them by first selecting the appropriate wire gauge and material to create the desired inductance value.

We then wound the wire around a central core made of a non-conductive material, such as ceramic or plastic.

The next step is to apply a color-coded band to the inductor to show its inductance value.

Painting a band of color on the inductor using a heat-resistant enamel paint does this. The number of bands and their colors will depend on the inductance value and tolerance of the inductor.

Each color corresponds to a number or multiplier that we used to calculate the inductance value of the inductor.

The first two bands show the significant digits of the inductance value, the third band is the multiplier, and the fourth band represents the tolerance of the inductor.

After the color bands have applied, we typically coat the inductor with a protective layer of clear enamel to protect the paint from damage during handling and use.

We trimmed the leads of the inductor to the length and any excess wire we remove.

3.4.2 Inductor Color Code

Inductors are often color-coded to show their value, just like resistors are.

The color code comprises a series of colored bands painted around the inductor.

Each color represents a different number, and we arranged the colors in a specific order to represent the inductor’s value.

Common color code for inductors is:

Black: 0

Brown: 1

Red: 2

Orange: 3

Yellow: 4

Green: 5

Blue: 6

Violet: 7

Gray: 8

White: 9

NOTE: These color codes are for the common use of 4 band inductor specification. Military specification components have a different code for the multiplier and tolerance.

The color code gives the inductance in microhenry.

To calculate the value of a 4-band inductor, we need to determine the inductance value and tolerance based on the color codes on the inductor’s bands.

The color code for a 4-band inductor comprises four color bands.

The first two bands represent the significant digits of the inductance value, the third band represents the multiplier, and the fourth band represents the tolerance.

3.4.3 Example Calculations of Inductor Color Code

Example 1:

Band 1: Red

Band 2: Black

Band 3: Orange

Band 4: Gold

Step 1: Determine the significant digits. The first two bands represent the significant digits of the inductance value.

The color code for the Red band is 2 and for the Black band is 0. So, the first two significant digits are 20.

Step 2: Determine the multiplier. The third band represents the multiplier of the inductance value.

The color code for the orange band is 3, which is 1 follow by three zeros equal to 1,000. So, the multiplier is 1,000.

Step 3: Determine the inductance value. To determine the inductance value, we need to combine the significant digits and the multiplier.

So, we calculate the inductance value:

Inductance value = Significant digits × Multiplier = 20 × 1,000 = 20,000µH or 20mH

Therefore, the inductance value of the 4-band inductor with the color code Red-Black-Orange-Gold is 20mH.

Step 4: Determine the tolerance. The fourth band represents the tolerance of the inductor.

The color code for the Gold band is ±5%.

So, the tolerance of the inductor is ±5%.

So the actual value of the inductor can range from 19mH to 21mH.

Example 2:

Band 1: Red

Band 2: Yellow

Band 3: Red

Band 4: Silver

The first two bands show the first and second significant digits of the inductor value. Here, first band red represents 2, and second band yellow represents 4.

So the inductor value is 24.

The third band represents the multiplier. Here, red band represent 2, which is 1 follow by two zeroes equal to 100, so the multiplier is 100.

So the inductor value is 24 x 100 = 2400μH or 2.4mH.

The fourth band represents the tolerance, which shows the percentage range within which the inductor’s actual value may vary from its nominal value.

Here, silver represents a tolerance of ± 10%. So the actual value of the inductor can range from 2.16mH to 2.64mH.

So the inductor’s value is 2.4mH with a tolerance of ±10%.

Example 3:

Band 1: Orange

Band 2: Black

Band 3: Brown

Band 4: Gold

The first two bands show the first and second significant digits of the inductor value. Here, orange represents 3, and black represents 0.

So the inductor value is 30.

The third band represents the multiplier. Here, brown represents 10, so the multiplier is 10.

So the inductor value is 30 x 10 = 300μH.

The fourth band represents the tolerance, which shows the percentage range within which the inductor’s actual value may vary from its nominal value. I

Here, gold represents a tolerance of ± 5%. So the actual value of the inductor can range from 285μH to 315μH.

So the inductor’s value is 300μH with a tolerance of ±5%.

Air Core Inductor

Air core inductor looks like a coil or a spring made of wire. When electricity flows through the wire, it creates a magnetic field around the coil.

Unlike other types of inductors that use a metal core, an air core inductor doesn’t have any metal inside. Instead, it comprises just the wire coil and the surrounding air which act as a core. This makes it lighter and less expensive than other types of inductors.

Ferrite Core and Iron Core Inductor

We wound the coil of wire around the core, which is usually made of either iron or ferrite.

Ferrite Core

A ferrite core inductor has a core made of ferrite, which is magnetic. When electricity flows through the wire coil in a ferrite core inductor, it creates a magnetic field in the ferrite core, which stores the energy.

Ferrite is a ceramic compound comprising a mixed oxide of iron and one or more other metals which has “ferromagnetic” properties and we use it in high-frequency electrical components, such as aerials.

Ferrite core inductors are lighter and smaller, but they can’t store as much energy.

Iron Core

An iron-core inductor has a core made of iron. Iron metal is magnetic. When electricity flows through the wire coil in an iron-core inductor, it creates a magnetic field in the core and it stores the energy.

Iron core inductors are good for storing a lot of energy, but they can also be heavy.

Ferrite core inductors are lighter and smaller, but they can’t store as much energy.

3.4.4 Inductor Value Conversion

We measure inductors in units called “Henry,” but sometimes their values may be too small or too large to function in the correct way in an electronic circuit.

To overcome this issue, one can convert a inductor’s value from one unit to another.

Practitioners often use smaller units such as the microhenry (µH) and millihenry (mH) and since the Henry is a relatively large unit.

You can convert inductor values between nH, µH, mH, and Henry units.

To convert an inductor value from one unit to another, you can use the following formulas:

To convert Henry to millihenry:

Multiply the value in Henry by 1000.

For example, 0.1 Henry = 100 millihenry (0.1 * 1000)

To convert Henry to microhenry:

Multiply the value in Henry by 1,000,000.

For example, 0.1 Henry = 100,000 microhenry (0.1 * 1,000,000)

To convert Henry to nanohenry:

Multiply the value in Henry by 1,000,000,000.

For example, 0.1 Henry = 100,000,000 nanohenry (0.1 * 1,000,000,000)

To convert millihenry to microhenry:

Multiply the value in millihenry by 1000.

For example, 100 millihenry = 100,000 microhenry (100 * 1000)

To convert millihenry to nanohenry:

Multiply the value in millihenry by 1,000,000.

For example, 100 millihenry = 100,000,000 nanohenry (100 * 1,000,000)

To convert microhenry to nanohenry:

Multiply the value in microhenry by 1000.

For example, 100 microhenry = 100,000 nanohenry (100 * 1000)

The above table shows the conversion factors for inductance measurements in different units, including nH (nanohenry), uH (microhenry), mH (millihenry), and H (Henry).

The table lists values for increasing powers of ten, with each row showing the equivalent values in each of the four units.

For example, 1nH is equal to 0.001µH, 0.000001mH, and 0.000000001H.

3.4.5 Example Calculation to Convert a Value from µH to H

To convert microhenry to Henry, you need to divide the value by 1,000,000. For example, if you have an inductor of 100µH, the equivalent value in Henry would be:

100µH ÷ 1,000,000 = 0.0001H

Therefore, 100µH is equivalent to 0.0001H.

3.4.6 Example Calculation to Convert a Value from nH to µH

To convert nanohenry to microhenry, you need to divide the value by 1,000. For example, if you have an inductor of 10nH, the equivalent value in microhenry would be:

10nH ÷ 1,000 = 0.01µH

Therefore, 10nH is equivalent to 0.01µH.

3.4.7 Example Calculation to Convert a Value from mH to H

To convert millihenries to Henry, you need to multiply the value by 0.001. For example, if you have an inductor of 5mH, the equivalent value in Henry would be:

5mH x 0.001 = 0.005H

Therefore, 5mH is equivalent to 0.005H.

3.4.8 Inductors in Series

We connect inductors one after the other in a circuit, allowing the current to flow through each one. They are in series.

The total inductance of inductors in series is the sum of their individual inductances.

As we add more inductors into series, the total inductance increases.

There are several reasons we might want to connect inductors in series.

First, it enables us to create a circuit with a specific total inductance, which can be crucial in tuning circuits or filters where the desired result depends on the inductance of the circuit.

Second, connecting inductors in series can help us create a circuit that can handle high currents.

When the current flows through an inductor, it generates a magnetic field that opposes the current flow, potentially causing a voltage spike that can damage the circuit.

By connecting multiple inductors in series, we can distribute the current across them and reduce the risk of damage.

This means that if you have two inductors, one with an inductance of 10mH and another with an inductance of 20mH, and you connect them in series, the total inductance of the circuit will be 30mH (10mH + 20mH) as shown in the illustration below.

Total inductance L across points A and B = 30mH.

Series inductors are useful in electronic circuits, where you can limit the amount of current flowing through a particular part of the circuit.

By adding inductors in series, you can control the total inductance of the circuit.

To calculate the total inductance (L) of resistors in series, use the formula:

L = L1 + L2 + L3 +...

“L” stands for the total inductance of the inductors in series, and L1, L2, and L3, etc. stand for the inductance of each individual inductor.

3.4.9 Example Calculations of Inductors in Series

To calculate the total inductance of inductors in series, you add their inductances together.

Here are some examples of calculations for inductors in series.

Example 1

Two inductors in series, suppose you have two inductors with inductance values of 10mH and 20mH, respectively, which are connected in series.

To find the total inductance of the series combination, you add the inductance values together:

Total inductance = 10mH + 20mH = 30mH.

Therefore, the total inductance of the two inductors in series is 30mH.

Example 2

Three inductors in series, suppose you have three inductors with inductance values of 5mH, 10mH, and 15mH, respectively, that are connect in series.

To find the total inductance of the series combination, you add the inductance values together:

Total inductance = 5mH + 10mH + 15mH = 30mH.

Therefore, the total inductance of the three inductors in series is 30mH.

3.4.10 Inductors in Parallel

In electronics, an inductor is a component that resists changes in electrical current.

The inductors connected in parallel share the same two points of the circuit.

When inductors connect in parallel, their total inductance changes.

The total inductance of inductors connected in parallel is less than the inductance of the smallest individual inductor.

In simple terms, the combined inductance to changes in current differs from the inductance of each inductor on its own.

The inductors share the load of the electrical current, which reduces resistance.

Imagine a group lifting a heavy object and then thinking about inductors in parallel.

It might be hard for one person to lift the object alone.

However, when two or more people collaborate to lift an object, they can share the weight, making it significantly easier.

Likewise, when inductors connected in parallel, they resist changes in the current together.

This makes it easier for the electrical current to travel through the circuit, which can be useful in electronic devices.

This means that if you have two inductors, one with an inductance of 10mH and another with an inductance of 20mH, and you connect them in parallel, the total inductance of the circuit will be 6.67mH (1/10mH + 1/20mH).

Total inductance L across points A and B = 6.67mH.

To calculate the total inductance of inductors in parallel, use the formula:

1/L = 1/L1 + 1/L2 + 1/L3 +...

“1/L” stands for the total inductance of the inductors in parallel, and L1, L2, and L3, etc. stand for the inductance of each individual inductor.

3.4.11 Example Calculations of Inductors in Parallel

Example 1

Suppose we have two inductors in parallel with values L1 = 10mH and L2 = 20mH. What is the total inductance of the circuit?

To calculate the total inductance, we need to use the formula:

1/L = 1/L1 + 1/L2

Substituting the values, we get:

1/L = 1/10mH + 1/20mH

1/L = 0.1 + 0.05

1/Total = 0.15

Therefore, the total inductance of the circuit is:

L = 1/0.15

L = 6.67mH

Example 2

Three inductors are connect in parallel, with values of 5 mH, 10mH, and 20mH. Calculate the equivalent inductance.

1/L = 1/L1 + 1/L2 + 1/L3

1/L = 1/5mH + 1/10mH + 1/20mH

1/L = 0.2 + 0.1 + 0.05

1/L = 0.35

L = 2.86mH

3.4.12 Variable Inductor

A variable inductor (also known as variable coil) is an inductor we can adjust to have a different level of inductance.

Inductance is a measure of how much energy an inductor can store in its magnetic field.

By changing the inductance of a variable inductor, we can change the way it affects the flow of electricity in a circuit.

Variable inductors are useful in many electronic applications.

They can adjust the intensity of a light or the radio’s frequencies.

By changing the inductance of the variable inductor, we can change the way it interacts with other components in the circuit and achieve the desired effect.

3.4.13 Transformers

Transformers are devices that help us change the amount of voltage in an electrical circuit.

A transformer works by using two coils of wire wrapped around an iron core or ferrite core.

We use transformers to increase or decrease the voltage of an alternating current in a circuit.

They are devices that are used to transfer electrical energy between two or more circuits using electromagnetic induction.

They are commonly used to increase or decrease the voltage of an alternating current, which is useful for transmitting electrical power over long distances and for powering different electronic devices.

There are several types of electrical transformers, including step-up transformers, step-down transformers, and isolation transformers, each with its own specific uses and applications.

Primary and Secondary Coil

The coil of wire that is connected to the power source is called the primary coil.

Primary coil is the input of the transformer.

When an electric current flows through the primary coil, it creates a magnetic field around the coil.

The second coil of wire is called the secondary coil, and it is near the primary coil.

Secondary coil is the output of the transformer.

The magnetic field created by the current flowing through the primary coil induces a current in the secondary coil.

The amount of current induced in the secondary coil depends on the number of turns of wire in the coil.

Transformers are important in electronics because they allow us to change the voltage of an electrical signal.

By using a transformer, we can increase or decrease the voltage of an electrical signal without changing the frequency of the signal, but at a different voltage at secondary coil than the first coil.

This is useful in many applications, such as in power distribution and electronic devices.

We use transformers in many electronic devices, such as power adapters for charging phones and laptops, and even in the power lines that bring electricity to our homes.

They’re important because they help us safely and efficiently transmit electrical energy over long distances and change the voltage to match the needs of different electronic devices.

Non Center-tapped and Center-tapped

A Non center-tapped transformer is a type of transformer that only has one coil on each side of the metal core.

This differs from a Center-tapped transformer, which has a coil that is split in half, with a center connection point.

The Non Center-tapped transformer we use in many electronic devices, such as power supplies, audio amplifiers, and radios.

In a transformer, there is called a “center-tapped” coil. This means we divide the coil into two parts and there is a connection in the middle.

A center-tapped transformer has a wire in the middle of the coil that is connected to the ground.

This helps to create two separate circuits within the transformer, which we can use for different purposes.

Step-up Transformer

Step-up transformer is a device we used to increase the voltage of an electrical signal.

The primary coil generates a magnetic field around itself when an electrical signal passes through it.

A step-up transformer increases the voltage of the input signal.

We achieve this by having more turns in the secondary coil than in the primary coil.

For example, if the primary coil has 10 turns and the secondary coil has 100 turns, the voltage in the secondary coil will be 10 times higher than the voltage in the primary coil.

Step-up transformers we use in many electronic devices, such as power supplies and audio amplifiers.

We also use them in the electricity grid to increase the voltage of electricity before we transmit it over long distances, which helps to reduce power loss.

Step-down Transformer

A step-down transformer is an electrical device that helps to reduce the voltage of an alternating current (AC) signal.

In a step-down transformer, the coil of wire on the input side (primary coil) has more turns of wire than the output side (secondary coil).

When an AC signal applies to the primary coil, it creates a magnetic field around the coil, which then induces a voltage in the secondary coil.

Number of turns of wire in the secondary coil is fewer than the primary coil. The voltage induced in the secondary coil is lower than the voltage applied to the primary coil.

For example, imagine you have a step-down transformer with a primary coil that is connected to a wall outlet that supplies 120 volts AC/60Hz or 220 Volts AC/50Hz.

This lower voltage can then power electronic devices that require a lower voltage to operate safely.

3.5 Semiconductor Diodes

Diodes are electronic components that allow current to flow in only one direction.

They comprise a semiconductor material with a p-n junction, which acts as a one-way valve for current flow.

Several scientists and engineers developed the semiconductor diode over time rather than a single person.

However, a team of researchers, led by the American physicist Russell Ohl, developed the first practical semiconductor diode in 1940.

While working at Bell Labs, Ohl made the discovery of the p-n junction, which forms the basis of the semiconductor diode.

By adding an impurity to a pure semiconductor crystal created a boundary layer between two regions with different electrical properties, which functioned like a one-way valve for electrical current.

Diode has two pins, which are like the “legs” of the component. One pin is called the “anode,” and the other pin is called the “cathode.”

Imagine the diode as a street that only allows one-way traffic. The street (diode) permits the flow of cars (or electricity) in a single direction, from the entrance (anode) to the exit (cathode).

When incorporating diode into a circuit, make sure that anode connects to the origin of the electricity and the cathode connects to the destination of the electricity.

This way, the diode permits the flow of electricity in the desired direction.

To control the flow of electricity in one direction, connect the anode to the electricity source and the cathode to the desired endpoint using the diode.

When a voltage applies in the correct direction, current flows easily through the diode.

When the voltage applies in the opposite direction, the diode blocks the current flow.

We commonly use diodes in electronic circuits to rectify AC signals, to protect against reverse voltage, and to regulate voltage levels.

Different diodes exist for different applications. In the next sections, we are discussing the most common use power diode, signal diode and light-emitting diode (LED).

3.5.1 Light-Emitting Diode (LED)

LED is an electronic component that produces light when electricity flows through it.

LEDs differ from traditional light bulbs that use a filament or gas to produce light commonly used in homes. LED use a semiconductor rather than a filament to generate light.

Nick Holonyak Jr. was an American engineer and educator. He noted particularly for his 1962 invention and first demonstration of a semiconductor laser diode that emitted visible light.

Oleg Vladimirovich Losev was a Russian scientist and inventor who made significant discoveries in semiconductor junctions and the light-emitting diode (LED).

He observed light emission from carborundum point-contact junctions, constructing a light-emitting diode, did the first research on them, proposed the first correct theory of how they worked, and used them in practical applications such as electroluminescence.

LEDs are highly efficient in converting electricity into light, making them a popular choice for electronic devices such as phone screens, TVs, and traffic lights.

The semiconductor material in LED can conduct electricity under certain conditions, causing electrons to move and produce light when electricity flows through it.

LEDs rely on a process called electroluminescence. This means that when electrons move through a semiconductor material, they release energy as light.

LEDs are available in various colors, including red, green, blue, yellow, and white.

We apply a voltage across an LED, current flows through it, and the LED emits light.

Each LED color has a specific voltage drop, which is the amount of voltage that the LED needs to turn on and emit light.

Voltage drop depends on the specific LED, but blue and white LEDs have higher voltage drops than red, green, and yellow LEDs.

This means that you need to apply more voltage to a blue or white LED to make it turn on and emit light compared to a red, green, or yellow LED.

LEDs have a long lifespan and are very durable, which means they can last for many years without needing to be replaced.

LEDs come in many shapes, sizes, and colors.

You might have seen red LEDs in a remote control, green LEDs in a calculator, or blue LEDs in a digital clock.

There are even LEDs that can change color or blink on and off in distinct patterns!

One of the great things about LEDs is that they are very energy efficient.

They use much less power than traditional light bulbs and can last much longer too. This means that they are perfect for portable devices like smartphones or tablets, where battery life is important.

Another advantage of LEDs is that they are very durable.

They don’t have a fragile filament like traditional bulbs, so they can withstand shocks and vibrations without breaking.

This makes them ideal for toys, where they are rough play.

LEDs are also versatile. We can use them in many applications, from lighting up a small indicator on a circuit board to provide bright illumination for a room or outdoor space.

They can even create colorful displays or signs.

3.5.2 Signal Diode

Signal diodes are a type of diode commonly used in electronic circuits to process small electrical currents or voltages carrying information, also known as signals.

We use them in electronic devices such as radios, TVs, and other devices that receive signals from antennas or other sources to process, control, and manipulate signals while ensuring that the device receives interference-free signals.

Signal diodes help protect electronic devices from damage by limiting the voltage that can pass through the circuit.

3.5.3 Power Diode

Power diodes can handle a large amount of electrical power without breaking down.

We often use them in power supply and electrical circuits that demand high power-handling capabilities.

Similar to a large, sturdy pipe that can handle a high volume of water without bursting, power diodes can handle a significant amount of electricity without getting damaged.

3.6 Transistors

Transistors are electronic components that amplify or switch electronic signals.

They comprise a semiconductor material with three layers, which are doped to create two p-n junctions.

Most common type of transistor is the bipolar junction transistor (BJT).

We use transistors in electronic circuits as amplifiers, switches, and to control the flow of current.

3.6.1 Bipolar Junction Transistor (BJT)

BJT, or Bipolar Junction Transistor, is an important component in electronic circuits. It is a tiny device that can amplify or switch electronic signals.

BJT has three terminals: the emitter, the base, and the collector.

The transistor’s electricity originates from the “emitter” terminal, which facilitates its flow to other circuit components.

The “collector” terminal serves as the terminal point for the electricity, collecting it after passing through the BJT and transmitting it to other circuit components.

The “base” terminal functions as the control center of the transistor, determining the amount of electricity that should flow from the emitter to the collector.

When a small signal applies to one part of the transistor, it allows a larger current to flow through another part of the transistor.

This makes it useful for amplifying signals.

When a small current flows into the base, it controls a larger current flow between the emitter and collector.

Think of BJT like a switch that another electrical signal can control.

Electronics employ BJT as a switch, whereby a small signal applied to the transistor turns it ON or OFF, permitting or hindering the current flow in a circuit.

It is useful in digital electronics, where you want to turn things off.

PNP and NPN Transistors

Transistors are electronic components that can control the flow of electricity in a circuit.

PNP and NPN transistors are tiny switches that can turn on and off. There are two main types of transistors: PNP and NPN.

PNP and NPN transistors have unique structures but work in the same manner.

PNP and NPN transistors have different symbols that are used to represent them in circuit diagrams.

It’s important to note that the symbols for PNP and NPN transistors may look similar to you who are just learning about electronics.

It’s important to pay close attention to the arrow mark direction in the symbol to determine whether it represents a PNP or NPN transistor.

They each have three parts: a base, a collector, and an emitter.

A small amount of electricity applies to the base. It can control the flow of a larger amount of electricity between the collector and the emitter.

PNP transistor

A PNP transistor makes the base of a material with missing electron.

A small amount of electricity applies to the base. It creates a “hole” that attracts electrons from the emitter, which allows a larger amount of electricity to flow from the emitter to the collector.

Applying electricity to the base of a PNP transistor turns it off, effectively making it function as a switch.

The symbol for a PNP transistor looks like an arrow pointing inward to the base.

The arrow represents the direction of current flow in the transistor, which is opposite to the direction of current flow in an NPN transistor.

The current in a PNP transistor flows from the emitter to the base and then to the collector.

NPN transistor

The NPN transistor makes the base of a material with extra electrons.

Applying a small amount of electricity to the base causes it to attract some electrons from the emitter, enabling a larger amount of electricity to flow from the collector to the emitter.

The NPN transistor acts like a switch when electricity applies to the base.

The symbol for an NPN transistor looks like an arrow pointing outward from the base.

The arrow represents the direction of current flow in the transistor, which is opposite to the direction of current flow in a PNP transistor.

The NPN transistor allows the current to flow from the collector to the base and from the base to the emitter.

3.7 Integrated Circuit (IC)

An Integrated Circuit (IC) is a tiny electronic device that has many parts, such as transistors, resistors, and capacitors, all packed into a single piece of material called a semiconductor.

The invention of the integrated circuit (IC) credit goes to Jack Kilby of Texas Instruments and Robert Noyce of Fairchild Semiconductor, who independently developed the technology in the late 1950s and early 1960s.

Kilby’s work resulted in the first prototype IC in 1958, while Noyce’s work led to the development of a practical IC in 1959.

Both Kilby and Noyce are co-inventors of the integrated circuit.

Before ICs, electronic devices were much bigger and more complex because they required many components.

With ICs, we can make electronic devices much smaller and more efficient.

Imagine a miniature electronic metropolis constructed on a solitary plot of land, where all buildings and roads are interconnected.

This micro-city possesses many capabilities, such as aiding in data processing for computers or directing the locomotion of robots.

We use ICs in many electronic devices that we use every day, such as computers, smartphones, televisions, cars, and even toys.

They’re an important part of modern technology and help us do many things more easily and efficiently.

They help make these devices smaller, faster, and more efficient.

3.8 How to Identify and Read the Value of Components

-To read the value of components in electronics, follow these steps:

-Identify the component

-Determine what the component is by examining it. Is it a resistor, capacitor, or inductor, for example?

-Read the markings

-Most components will have markings on them that show their value.

-Resistors, for example, will have colored bands that correspond to specific values.

-Capacitors may have a numerical value printed on them, along with a unit of measurement, such as farads (F) or microfarads (μF).

-Interpret the markings

-Once you have identified the markings on the component, you need to interpret them to determine the component’s value.

-For resistors, use a color code chart to match the colored bands to specific values.

-For capacitors, the numerical value will show the capacitance in farads or microfarads.

-Check the tolerance

-Many components will also have a tolerance rating, which shows how much the actual value of the component may differ from the stated value.

-We usually show this as a percentage.

-Verify your readings

Finally, it is important to verify your readings using a multimeter or other measuring device to ensure that the component is functioning as expected and its value matches what you have determined.

Multiple Choice Questions and Answers

Chapter 3

Basic Components

3.1 Switches

Question 1: What are switches?

A. Components that allow us to control the flow of electricity in a circuit.

B. Components used to block current all the time.

C. Components used to allow voltage all the time.

Answer: A. Components that allow us to control the flow of electricity in a circuit.

Question 2: What does a switch do?

A. It allows or prevents the flow of electricity in a circuit.

B. It makes a noise when you press it.

C. It changes its body color when you press it.

Answer: A. It allows or prevents the flow of electricity in a circuit.

Question 3: What happens when a switch is in the “on” position?

A. It completes the circuit, allowing electricity to flow.

B. It breaks the circuit, preventing the flow of electricity.

C. It doesn’t do anything.

Answer: A. It completes the circuit, allowing electricity to flow.

Question 4: What happens when a switch is in the “off” position?

A. It breaks the circuit, preventing the flow of electricity.

B. It completes the circuit, allowing electricity to flow.

C. It makes a buzzing sound.

Answer: A. It breaks the circuit, preventing the flow of electricity.

Question 5: What are some types of switches?

A. SPST, DPDT, push to on, toggle, rocker, and domestic light switch.

B. APDT and DSPT

C. APDT, DSPT and XPDT.

Answer: A. SPST, DPDT, push to on, toggle, rocker, and domestic light switch.

Question 6: Why are switches important?

A. They allow us to control when and how electricity flows through a circuit.

B. They make a room look nicer.

C. They are fun to play with.

Answer: A. They allow us to control when and how electricity flows through a circuit.

Question 7: What can you do by understanding how switches work?

A. Explore the world of electronics and begin building your own circuits and devices.

B. Switch on and watch TV all day.

C. Switch on video games and play all day.

Answer: A. Explore the world of electronics and begin building your own circuits and devices.

3.1.1 SPST Switch

Question 1: What does SPST stand for?

A. Simple-Pole-Simple-Throw

B. Single-Pole-Single-Throw

C. Single-Position-Single-Turn

D. Switch-Pole-Simple-Throw

Answer: B. Single-Pole-Single-Throw

Question 2: How many positions does a SPST switch have?

A. 1

B. 2

C. 3

D. 4

Answer: B. 2

Question 3: What happens when an SPST switch is in the “on” position?

A. It blocks the flow of electricity.

B. It allows the flow of electricity through the circuit.

C. It reverses the direction of electricity.

D. It creates a short circuit. 

Answer: B. It allows the flow of electricity through the circuit.

Question 4: Which analogy is used in the text to explain the function of an SPST switch?

A. A window

B. A mirror

C. A door

D. A book

Answer: C. A door

Question 5: What can SPST switches be used for?

A. Turning devices on or off.

B. Controlling the speed of devices.

C. Changing the color of devices.

D. Making devices smaller.

Answer: A. Turning devices on or off.

3.1.2 SPDT Switch

Question 1: What does the “Single-Pole” part of SPDT mean?

A. The switch has one input of electrical power.

B. The switch has two inputs of electrical power.

C. The switch has three inputs of electrical power.

Answer: A. The switch has one input of electrical power.

Question 2: What does the “Double-Throw” part of SPDT mean?

A. The switch can connect or disconnect power to one output.

B. The switch can connect or disconnect power to two different outputs.

C. The switch can connect or disconnect power to three different outputs.

Answer: B. The switch can connect or disconnect power to two different outputs.

Question 3: When the switch is on in one position, what happens to the circuit connected to it?

A. The connected circuit becomes “open” and stops electricity to flow.

B. The connected circuit becomes “closed” and allow electricity from flowing.

C. The circuit connected becomes “shorted” and causes a spark.

Answer: B. The connected circuit becomes “closed” and allow electricity from flowing.

Question 4: When the switch is off in one position, what happens to the circuit connected to it?

A. The connected circuit becomes “open” and stops electricity to flow.

B. The connected circuit becomes “closed” and allow electricity from flowing.

C. The circuit connected becomes “shorted” and causes a spark.

Answer: A. The connected circuit becomes “open” and stops electricity to flow.

3.1.3 DPDT Switch

Question 1: What does DPDT stand for?

A. Double-Pole Double-Touch

B. Double-Pole Double-Throw

C. Double-Power Double-Transmission

Answer: B. Double-Pole Double-Throw

Question 2: What is a DPDT switch used for in electronic circuits?

A. To change the direction of the current flowing through it.

B. To generate electricity.

C. To amplify sound waves.

Answer: A. To change the direction of the current flowing through it.

Question 3: How many independent sets of contacts does a DPDT switch have?

A. One

B. Two

C. Three

Answer: B. Two

Question 4: What kind of switch is a railway switch that changes the direction of a train and moves both sets of contacts simultaneously?

A. SPST switch

B. SPDT switch

C. DPDT switch

Answer: C. DPDT switch

Question 5: What happens when a DPDT railway switch is in one position?

A. The train goes in one direction.

B. The train stops.

C. The train goes in the opposite direction.

Answer: A. The train goes in one direction.

Question 6: What is a common use of a DPDT switch in electronics?

A. To generate heat.

B. To switch between two different circuits.

C. To charge batteries.

Answer: B. To switch between two different circuits.

Question 7: How can you reverse the direction of two motors in your robot?

A. By disconnecting and reconnecting the motors manually.

B. By using a single pole single throw switch.

C. By using a DPDT switch.

Answer: C. By using a DPDT switch.

3.1.4 Slide Switch

Question 1: What is a slide switch?

A. A type of electronic device.

B. A simple type of switch used in electronic devices.

C. A small plastic or metal lever.

D. All of the above.

Answer: B. A simple type of switch used in electronic devices.

Question 2: What is the function of a slide switch?

A. To turn on and off electronic devices.

B. To automatically control the device’s power source.

C. To block electricity all the time to flow through the device.

D. All of the above.

Answer: A. To turn on and off electronic devices.

Question 3: Where are slide switches commonly used?

A. In large electronic devices.

B. In toys and flashlights.

C. In satellites.

D. None of the above.

Answer: B. In toys and flashlights.

Question 4: Why are slide switches popular in DIY electronics projects for kids and beginners?

A. They are inexpensive.

B. They are easy to use.

C. They are a simple way to turn circuits on and off.

D. All of the above.

Answer: D. All of the above.

Question 5: What happens when the slide switch is in the “off” position?

A. The device turns on.

B. The circuit breaks and electricity cannot flow.

C. The device becomes more powerful.

D. None of the above.

Answer: B. The circuit breaks and electricity cannot flow.

3.1.5 Momentary Push ON switch

Question 1: What is a momentary push on switch?

A. A switch that requires continuous pressure to stay on.

B. A switch that requires a momentary push to turn on and automatically turns off when the pressure is released.

C. A switch that can turn on by itself without any pressure.

Answer: B. A switch that requires a momentary push to turn on and automatically turns off when the pressure is released.

Question 2: Where can we use a momentary push on switch?

A. In a TV.

B. In a doorbell.

C. In a refrigerator.

Answer: B. In a doorbell.

Question 3: How does a momentary push on switch work in a doorbell?

A. It completes a circuit when you release the button.

B. It turns on by itself when someone is at the door.

C. It completes a circuit when you press the button and automatically turns off when you release the pressure.

Answer: C. It completes a circuit when you press the button and automatically turns off when you release the pressure.

Question 4: Why are momentary push on switches important in electronic devices?

A. They make the devices look cool.

B. They allow users to control and activate various functions with a simple push or press of a button.

C. They make the devices more expensive.

Answer: B. They allow users to control and activate various functions with a simple push or press of a button.

3.2 Resistors

Question 1: What are resistors used for in a circuit?

A. To increase the flow of current.

B. To decrease the flow of current.

C. To create an electric charge.

D. To power electronic devices.

Answer: B. To decrease the flow of current.

Question 2: What are resistors typically made of?

A. Rubber

B. Glass

C. Carbon or metal.

D. Plastic

Answer: C. Carbon or metal.

Question 3: What happens when electric current flows through a resistor?

A. The resistor becomes charged.

B. The resistor heats up.

C. The resistor vibrates.

D. The resistor emits light.

Answer: B. The resistor heats up.

Question 4: Why resistors are often color-coded?

A. To make them look pretty.

B. To help people identify their resistance value.

C. To make them not easier to break.

D. To confuse people.

Answer: B. To help people identify their resistance value.

Question 5: In what electronic devices are resistors commonly used?

A. Gas powered cars.

B. Mechanical optical instruments.

C. Radios, televisions, and computers.

D. Handmade musical instruments.

Answer: C. Radios, televisions, and computers.

Question 6: What do we measure the resistance of a resistor in?

A. Volts

B. Watts

C. Ohms

D. Amperes

Answer: C. Ohms

Question 7: Why are resistors often used to protect sensitive components?

A. To decrease the flow of current.

B.  To increase the flow of current.

C. To create an electric charge.

D. To power electronic devices.

Answer: A. To decrease the flow of current.

3.2.1 Fixed Value Resistor

Question 1: What measures a resistor’s ability to resist the flow of current?

A. Voltage

B. Current

C. Wattage

D. Resistance

Answer: D. Resistance

Question 2: How is the concept of electricity flow through a circuit compared to water flow through a pipes?

A. Electricity flows through a circuit, while water flows through a large canal.

B. Electricity flows through a battery, while water flows through a faucet.

C. Electricity flows through a computer, while water flows through a sprinkler.

D. Electricity flows through an electronic device, while water flows through a water tank.

Answer: B. Electricity flows through a battery, while water flows through a faucet.

Question 3: What happens to a resistor that experiences an excessive amount of current flow?

A. It becomes smaller in size.

B. It becomes larger in size.

C. It overheats and becomes damaged.

D. It becomes more effective.

Answer: C. It overheats and becomes damaged.

Question 4: Why is it crucial to use the appropriate resistor for each job?

A. To limit the amount of current flow in a circuit.

B. To increase the amount of current flow in a circuit.

C. To make the circuit more complicated.

D. To make the circuit well-organized.

Answer: A. To limit the amount of current flow in a circuit.

3.2.2 Resistor Color Code

Question 1: What is the system for identifying the value of a resistor?

A. The number system.

B. The letter system.

C. The color code.

D. The shape system.

Answer: C. The color code.

Question 2: How many bands can resistors have on their bodies?

A. 2

B. 4

C. 1

D. 7

Answer: B. 4

Question 3: Which bands on a 4-band resistor show the first two digits of the resistor's value?

A. The first and third bands.

B. The second and third bands.

C. The first and second bands.

D. The third and fourth bands.

Answer: C. The first and second bands.

Question 4: What does the third band on a 4-band resistor represent?

A. The actual value of the resistor.

B. The allowable deviation of the actual value from the stated value.

C. The multiplier, which determines the number of zeros that follow the first two digits.

D. The color of the resistor.

Answer: C. The multiplier, which determines the number of zeros that follow the first two digits.

Question 5: What does the fourth band on a 4-band resistor represent?

A. The actual value of the resistor.

B. The allowable deviation of the actual value from the stated value.

C. The multiplier, which determines the number of zeros that follow the first two digits.

D. The color of the resistor.

Answer: B. The allowable deviation of the actual value from the stated value.

3.2.6 Resistors Series Circuit

Question 1: When are resistors said to be in series?

A. When they are connected with no free end.

B. When they are connected end-to-end.

C. When they are connected in a loop.

Answer: B. When they are connected end-to-end.

Question 2: What happens to the total resistance of the circuit when resistors are connected in series?

A. It increases.

B. It decreases.

C. It remains the same.

Answer: A. It increases.

Question 3: If you connect two resistors in series, one with a resistance of 5 ohms and another with a resistance of 10 ohms, what will be the total resistance of the circuit?

A. 15 ohms

B. 5 ohms

C. 10 ohms

Answer: A. 15 ohms

Question 4: What happens to the voltage of the circuit when resistors are connected in series?

A. It increases

B. It decreases

C. It remains the same

Answer: B. It decreases

3.2.8 Resistors Parallel Circuit

Question 1: What happens when you add a resistor in parallel to an electronic circuit?

A. You create an additional pathway for electric current to flow.

B. You slow down the flow of electric current.

C. You stop the flow of electric current.

Answer: A. You create an additional pathway for electric current to flow.

Question 2: How is connect resistors in parallel different from connect them in series?

A. Connect resistors in parallel creates an extra road for the current to travel on.

B. Connect resistors in series creates an additional pathway for electric current to flow.

C. Connecting resistors in series is the same as connecting them in parallel.

Answer: A. Connect resistors in parallel creates an extra road for the current to travel on.

Question 3: How can connecting resistors in parallel protect other components in the circuit?

A. By slowing down the flow of electric current.

B. By creating an additional pathway for electric current to flow.

C. By increasing the flow of electric current.

Answer: B. By creating an additional pathway for electric current to flow.

Question 4: What happens when you connect two or more resistors in parallel?

A. Electricity flows through each resistor separately.

B. Electricity flows through each resistor in series.

C. Electricity flows through the resistors randomly.

Answer: A. Electricity flows through each resistor separately.

Question 5: Why is the total resistance of resistors connected in parallel less than the resistance of the smallest individual resistor?

A. Because electricity has multiple paths to follow, reducing the effort required to pass through the circuit.

B. Because electricity has to flow through each resistor in series, increasing the resistance.

C. Because electricity flows randomly through each resistor, reducing the resistance.

Answer: A. Because electricity has multiple paths to follow, reducing the effort required to pass through the circuit.

Question 6: How do you calculate the total resistance of resistors in parallel?

A. R = R1 + R2 + R3 +...

B.1/R = 1/R1 + 1/R2 + 1/R3 +...

C.1/R = R1 + R2 + R3 +...

Answer: B.1/R = 1/R1 + 1/R2 + 1/R3 +...

3.2.10 Variable Resistor

Question 1: What is a variable resistor?

A. A passive component that can change the amount of electrical current that flows through a circuit.

B. A passive component that can change the amount of magnetic field.

C. A passive component that can change the amount of electromagnetic field.

Answer: A. A passive component that can change the amount of electrical current that flows through a circuit.

Question 2: How does a variable resistor work?

A. By allowing the user to adjust the amount of resistance in the circuit.

B. By producing electrical current.

C. By connecting to three different circuits.

Answer: A. By allowing the user to adjust the amount of resistance in the circuit.

Question 3: How many terminals does a variable resistor have?

A. One

B. Two

C. Three

Answer: C. Three

Question 4: Which terminal of a variable resistor is used to adjust the resistance?

A. A (left)

B. B (center)

C. C (right)

Answer: B. B (center)

Question 5: What are some electronic devices that use variable resistors?

A. Radios, televisions, and dimmer switches for lights.

B. Yagi antennas, dish antennas, and mobile phone towers.

C. Laptops, mouse, and USB connectors.

Answer: A. Radios, televisions, and dimmer switches for lights.

Potentiometer

Question 6: What happens when you turn the shaft of a potentiometer?

A. The resistance stays the same.

B. The position of the wiper terminal changes, which changes the amount of resistance in the circuit.

C. The circuit turns off.

Answer: B. The position of the wiper terminal changes, which changes the amount of resistance in the circuit.

Question 7: Where are potentiometers commonly used?

A. In satellites to change its position in the space.

B. In dish antennas to change its direction.

C. In audio equipment to control volume and tone, and in other applications where a variable resistor is needed.

Answer: C. In audio equipment to control volume and tone, and in other applications where a variable resistor is needed.

Preset

Question 8: What is a preset?

A. A small potentiometer used to set a specific resistance value in a circuit.

B. A type of resistor that is always set at a fixed resistance value.

C. A tool used to measure the electrical current in a circuit.

Answer: A. A small potentiometer used to set a specific resistance value in a circuit.

Question 9: How many terminals does a preset have?

A. One

B. Two

C. Three

Answer: C. Three

Question 10:  What is the purpose of a screwdriver when using a preset?

A. To turn the preset on and off.

B. To adjust the resistance value to a specific level.

C. To measure the voltage levels and frequencies of the circuit.

Answer: B. To adjust the resistance value to a specific level.

Question 11: Can presets be adjusted multiple times after the initial setup of a circuit?

A. Yes

B. No

C. Only two times.

Answer: A. Yes

3.2.11 Light Dependent Resistor (LDR)

Question 1: What is an LDR?

A. A component that changes its resistance to incoming light on its sensitive surface.

B. A component that changes brightness of incoming light on its sensitive surface.

C. A device that emits light when it's exposed to light.

Answer: A. A component that changes its resistance to incoming light on its sensitive surface.

Question 2: Who discovered that selenium’s electrical resistance changes depending on the amount of light that falls on it?

A. Willoughby Smith

B. Thomas Edison

C. Alexander Graham Bell

Answer: A. Willoughby Smith

Question 3: What is the theoretical basis for television and photoelectric cells?

A. The discovery of photoresistors.

B. The photoconductivity of selenium.

C. The development of cadmium sulfide.

Answer: B. The photoconductivity of selenium.

Question 4: What type of material is commonly used to compose LDRs?

A. Plastic

B. Glass

C. Semiconductor material like cadmium sulfide or lead sulfide.

Answer: C. Semiconductor material like cadmium sulfide or lead sulfide.

Question 5: What is one common application of LDRs?

A. Measure motor torque.

B. Turn on lights when the ambient light level falls below a certain threshold.

C. Measure temperature and moisture.

Answer: B. Turn on lights when the ambient light level falls below a certain threshold.

Question 6:  What type of device uses LDRs to detect the level of sunlight and adjust its output?

A. Solar cell

B. TV

C. Radio

Answer: A. Solar cell

3.2.12 Thermistor

Question 1: What is a thermistor?

A. A device that detects changes in temperature.

B. A device that produces heat.

C. A device that detects changes in humidity.

D. A device that detects changes in pressure.

Answer: A. A device that detects changes in temperature.

Question 2: How does the resistance of a thermistor change with temperature?

A. It remains constant.

B. It only increases all the time.

C. It increases or decreases depend on temperature.

D. It fluctuates randomly.

Answer: C. It increases or decreases depend on temperature.

Question 3: Who discovered the first NTC thermistor?

A. Thomas Edison

B. Michael Faraday

C. Samuel Ruben

D. Benjamin Franklin

Answer: B. Michael Faraday

Question 4: When was the first commercially viable thermistor invented?

A. 1833

B. 1930

C. 1970

D. 2000

Answer: B. 1930

Question 5: What is the practical application of thermistors?

A. Controlling the temperature of a room or building.

B. Producing electricity.

C. Measuring humidity.

D. Measuring pressure.

Answer: A. Controlling the temperature of a room or building.

NTC and PTC Thermistor

Question 6: How many types of thermistors are there?

A. One

B. Two

C. Three

Answer: B. Two

Question 6: What does NTC stand for?

A. Negative Temperature Coefficient.

B. Non-Technical Component.

C. New Thermal Circuit.

Answer: A. Negative Temperature Coefficient.

Question 7: What happens to the resistance of NTC thermistors as the temperature rises?

A. It remains the same.

B. It increases.

C. It decreases.

Answer: C. It decreases.

Question 8: In which applications are NTC thermistors commonly used?

A. Overcurrent protection.

B. Inrush current limiting.

C. Temperature control and sensing.

Answer: C. Temperature control and sensing.

Question 9: What does PTC stand for?

A. Positive Temperature Circuit.

B. Personal Technology Companion.

C. Positive Temperature Coefficient.

Answer: C. Positive Temperature Coefficient.

Question 10: What happens to the resistance of PTC thermistors as the temperature increases?

A. It remains the same.

B. It decreases.

C. It increases.

Answer: C. It increases.

3.3 Capacitors

Question 1: What are capacitors?

A. Devices that store electrical energy in a magnetic field.

B. Devices that store electrical energy in an electric field.

C. Devices that store magnetic energy in an electric field.

Answer: B. Devices that store electrical energy in an electric field.

Question 2: Who is Michael Faraday?

A. A British scientist who made significant contributions to the fields of electromagnetism and electrochemistry during the 19th century.

B. An American scientist who discovered electricity.

C. An Indian scientist who discovered the properties of capacitance.

Answer: A British scientist who made significant contributions to the fields of electromagnetism and electrochemistry during the 19th century.

Question 3: What is the unit of electrical capacitance?

A. Volt

B. Watt

C. Farad

Answer: C. Farad

Question 4: What are most fixed value capacitors measured in?

A. Only in Megafarads (MF)

B. Microfarads (µF) or picofarads (pF) or nanofarads (nF)

C. Only in Nanofarads (nF)

Answer: B. Microfarads (µF) or picofarads (pF) or nanofarads (nF)

Question 5: How are capacitors constructed?

A. They comprise two conductive plates separated by a magnetic material.

B. They comprise two conductive plates separated by a conductive material.

C. They comprise two conductive plates separated by a non-conductive material, such as air, plastic etc.

Answer: C. They comprise two conductive plates separated by a non-conductive material, such as air, plastic etc.

Question 6: What happens when a voltage is applied to a capacitor?

A. It creates a magnetic field.

B. It creates an electric field between the plates, which stores energy.

C. It creates a current flow between the plates.

Answer: B. It creates an electric field between the plates, which stores energy.

Question 7: What are the common uses of capacitors in electronic circuits?

A. To amplify signals.

B. To filter out noise, smooth out voltage fluctuations, and to store energy for short periods of time.

C. To generate electricity.

Answer: B. To filter out noise, smooth out voltage fluctuations, and to store energy for short periods of time.

Question 8: What are the two types of capacitors?

A. High value and low value

B. Polarized and non-polarized

C. High value and medium value

Answer: B. Polarized and non-polarized

Question 9: How do polarized capacitors differ from non-polarized capacitors?

A. Polarized capacitors have a positive and negative lead, while non-polarized capacitors do not have any polarity and can connect in either direction.

B. Polarized capacitors are smaller than non-polarized capacitors.

C. Polarized capacitors have higher capacitance than non-polarized capacitors.

Answer: A. Polarized capacitors have a positive and negative lead, while non-polarized capacitors do not have any polarity and can connect in either direction.

3.3.1 Fixed value Capacitor

Question 1: What is a fixed value capacitor?

A. A capacitor that can store a specific amount of electrical charge and we can change its capacitance.

B. A capacitor that can store a specific amount of electrical charge and we cannot change its capacitance.

C. A capacitor that can store an unlimited amount of electrical charge.

Answer: B. A capacitor that can store a specific amount of electrical charge and we cannot change its capacitance.

Question 2: What are the functions of fixed value capacitors in electronic devices?

A. Filtering out unwanted noise, smoothing out voltage fluctuations, and coupling one circuit to another.

B. Generating electrical charge and increasing voltage fluctuations.

C. Creating noise and disrupting circuit connections.

Answer: A. Filtering out unwanted noise, smoothing out voltage fluctuations, and coupling one circuit to another.

Question 3: What does a capacitor value code of 104 represent?

A. 1pF

B. 10nF

C. 0.1µF

Answer: C. 0.1µF

3.3.2 Ceramic Disc Capacitor

Question 1: What is a Ceramic Disc Capacitor?

A. A type of capacitor with a ceramic disc as the dielectric.

B. A type of capacitor with two metal discs as the dielectric.

C. A type of metal plate used in a circuit.

D. A type of variable capacitor.

Answer: A. A type of capacitor with a ceramic disc as the dielectric.

Question 2: What is the function of a Ceramic Disc Capacitor in electronics?

A. To generate electricity.

B. To filter out unwanted electrical signals.

C. To generate and transmit electricity to electronic devices.

D. To use as a battery replacement in electronic devices.

Answer: B. To filter out unwanted electrical signals.

Question 3: What is the structure of a Ceramic Disc Capacitor?

A. It consists of two metal plates separated by a ceramic disc.

B. It consists of two plastic plates separated by a ceramic disc.

C. It consists of a single metal plate and single ceramic disc.

D. It consists of two ceramic plates separated by a metal disc.

Answer: A. It consists of two metal plates separated by a ceramic disc.

Question 4: What happens when electricity flows into a Ceramic Disc Capacitor?

A. The ceramic disc charges up.

B. The metal plates charge up.

C. The ceramic disc releases stored energy.

D. The metal plates release stored energy.

Answer: B. The metal plates charge up.

Question 5: What is the purpose of using different sizes and capacitance values of Ceramic Disc Capacitors?

A. To make the circuit look cool.

B. To make the circuit more attractive.

C. To meet the specific needs of the electronic circuit.

D. To make the circuit work faster.

Answer: C. To meet the specific needs of the electronic circuit.

3.3.11 Electrolytic Capacitor

Question 1: What is an electrolytic capacitor?

A. A type of polarized component used in circuits to store electrical energy.

B. A type of non-polarized component used in circuits to store electrical energy.

C. A type of component used in circuits to block power.

D. A type of active component to generate electricity.

Answer: A. A type of polarized component used in circuits to store electrical energy.

Question 2: What is the electrolyte in an electrolytic capacitor?

A. A dielectric solid that is sandwiched between two metal plates.

B. A special coating on the metal plates.

C. A type of gas that is sandwiched between two metal plates.

D. A liquid or gel that is sandwiched between two metal plates.

Answer: D. A liquid or gel that is sandwiched between two metal plates.

Question 3: What is the purpose of oxide layer on the metal plates of an electrolytic capacitor?

A. It conducts electrical charge.

B. It discharges electrical energy in the capacitor quickly.

C. It avoids rusting of metal plates.

D. It act as the dielectric of the capacitor.

Answer: D. It act as the dielectric of the capacitor.

Question 4: What is the purpose of using electrolytic capacitors in power supplies?

A. To create electrical energy.

B. To discharge electrical energy quickly.

C. To filter out noise and provide a stable source of power.

D. To remove electrical charge from the circuit.

Answer: C. To filter out noise and provide a stable source of power.

Question 5: Why is the polarity of an electrolytic capacitor important?

A. It can damage or even explode if connected to the wrong way.

B. It increases the amount of electrical charge stored in the capacitor.

C. It improves the quality of the electrical signal.

D. It makes the capacitor more resistant to noise.

Answer: A. It can damage or even explode if connected to the wrong way.

3.3.12 Capacitors in Series

Question 1: What happens when multiple capacitors are connected in series?

A. They create a single chain with total capacitance equal to the sum of individual capacitances.

B. They create a single chain with total capacitance equal to the multiplication of individual capacitances.

C. Total capacitance value become smaller.

Answer: C. Total capacitance value become smaller.

Question 2: Why is connecting capacitors in series useful?

A. To decrease the total capacitance.

B. To increase the total capacitance without using a single, very large capacitor.

C. To make the circuit more attractive.

Answer: A. To decrease the total capacitance.

Question 3: What is the formula for capacitors in series?

A. Total Capacitance = C1 + C2 + C3 +...

B. Total Capacitance = 1 / (1/C1 + 1/C2 + 1/C3 +...)

C. Total Capacitance = C1 * C2 * C3 *...

Answer: B. Total Capacitance = 1 / (1/C1 + 1/C2 + 1/C3 +...)

Question 4: Why is the total capacitance of capacitors connected in series less than any individual capacitance?

A. Because it multiplies the effective distance between the plates of each capacitor, resulting in less charge storage capacity.

B. Because it decreases the effective distance between the plates of each capacitor, resulting in less charge storage capacity.

C. Because it increases the effective distance between the plates of each capacitor, resulting in less charge storage capacity.

Answer: C. Because it increases the effective distance between the plates of each capacitor, resulting in less charge storage capacity.

3.3.14 Capacitors in Parallel

Question 1: What happens to the total capacitance when capacitors are connected in parallel?

A. It decreases.

B. It remains the same.

C. It increases.

Answer: C. It increases.

Question 2: What happens to the overall voltage rating of capacitors when they are connected in parallel?

A. It decreases.

B. It remains the same.

C. It increases.

Answer: B. It remains the same.

Question 3: What happens to the voltage across each capacitor when they are connected in parallel?

A. It decreases.

B. It remains the same.

C. It increases.

Answer: B. It remains the same.

Question 4: How can we determine the total capacitance of capacitors in parallel?

A. By subtracting the capacitance values of each capacitor.

B. By multiplying the capacitance values of each capacitor.

C. By adding the capacitance values of each capacitor.

Answer: C. By adding the capacitance values of each capacitor.

Question 5: Why does the total charge stored in parallel capacitors equal the sum of the charges stored in each individual capacitor?

A. Because the voltage across each capacitor changes.

B. Because the charge stored in each capacitor is inversely proportional to its capacitance.

C. Because the voltage across each capacitor remains the same and the charge stored in each capacitor is directly proportional to its capacitance.

Answer: C. Because the voltage across each capacitor remains the same and the charge stored in each capacitor is directly proportional to its capacitance.

3.3.14 Variable Capacitor

Question 1: What is a variable capacitor used for in radio tuners?

A. To store electrical energy.

B. To adjust the capacitance of the circuit.

C. To filter out unwanted signals.

D. To make the radio louder.

Answer: C. To filter out unwanted signals.

Question 2: How can we adjust the capacitance of a variable capacitor?

A. By changing the color of the capacitor.

B. By adjusting the position of one of the plates using a knob or screw.

C. By changing the size of the capacitor.

D. By connecting it to a power source.

Answer: B. By adjusting the position of one of the plates using a knob or screw.

Question 3: What happens to the capacitance of a variable capacitor when the plates are closer together?

A. The capacitance decreases.

B. The capacitance increases.

C. The capacitance remains the same.

D. The capacitor stops working.

Answer: B. The capacitance increases.

Question 4: In what other applications might we use a variable capacitor?

A. Solar cells.

B. Light sensitive circuits.

C. Temperature sensors.

D. Oscillators, filters, and resonant circuits.

Answer: D. Oscillators, filters, and resonant circuits.

3.4 Inductors

Question 1: What are inductors?

A. Devices that store energy in a magnetic field.

B. Devices that generate electricity.

C. Devices that helps store energy in the dielectric.

D. Devices that helps store energy in a battery.

Answer: A. Devices that store energy in a magnetic field.

Question 2: Who pioneered the construction of strong, practical electromagnets and built one of the first electromagnetic motors?

A. Thomas Edison

B. Benjamin Franklin

C. Joseph Henry

D. Nikola Tesla

Answer: C. Joseph Henry

Question 3: What is the unit of inductance named after Joseph Henry?

A. Farad (F)

B. Henry (H)

C. Ohm (Ω)

D. Volt (V)

Answer: B. Henry (H)

Question 4: How do we define one Henry of inductance?

A. The amount of resistance that an inductor generates when the current passing through it changes at a rate of one ampere per second.

B. The amount of current that an inductor generates when the resistance passing through it changes at a rate of one volt per second.

C. The amount of inductance that an inductor generates when the current passing through it changes at a rate of one ampere per second, inducing an electromotive force of one volt.

D. The amount of voltage that an inductor generates when the current passing through it changes at a rate of one ampere per second.

Answer: C. The amount of inductance that an inductor generates when the current passing through it changes at a rate of one ampere per second, inducing an electromotive force of one volt.

Question 5: What are the smaller units of inductance that practitioners often use?

A. kilohenry (kH) and centihenry (cH)

B. millihenry (mH) and microhenry (µH)

C. decihenry (dH) and nanohenry (nH)

D. gigahenry (GH) and terahenry (TH)

Answer: B. millihenry (mH) and microhenry (µH)

Question 6: What creates a magnetic field in an inductor?

A. Inbuilt resistor.

B. Inbuilt battery.

C. Inbuilt capacitor.

D. A coil of wire.

Answer: D. A coil of wire.

Question 7: What does the strength of the magnetic field in an inductor depend on?

A. The color of the wire.

B. The type of metal used in the coil.

C. The number of turns in the coil and the amount of current flowing through it.

D. The size of the inductor.

Answer: C. The number of turns in the coil and the amount of current flowing through it.

Question 8: Why do we commonly use inductors in electronic circuits?

A. To generate electricity.

B. To filter out noise and block DC signals.

C. To filter out noise and block AC signals.

D. To control the temperature of the circuit.

Answer: C. To filter out noise and block AC signals.

3.4.1 Fixed Value Inductor

Question 1: What is a fixed value inductor?

A. A component that stores energy in a magnetic field when an electric current passes through it.

B. A device that generates electricity.

C. A type of battery.

Answer: A. A component that stores energy in a magnetic field when an electric current passes through it.

Question 2: What is the measure of how much energy a fixed value inductor can store?

A. Resistance

B. Capacitance

C. Inductance

Answer: C. Inductance

Question 3: What is an example of how a fixed value inductor can be useful in electronic circuits?

A. To generate electricity.

B. To regulate the flow of electricity.

C. To control the temperature of the circuit.

Answer: B. To regulate the flow of electricity.

Question 4: Why are they called "fixed" value inductors?

A. Because they are very heavy.

B. Because they can be fixed in one place.

C. Because their inductance value is unchanging.

Answer: C. Because their inductance value is unchanging.

Question 5: What is the difference between fixed value inductors and variable inductors?

A. Fixed value inductors have a specific, unchanging value of inductance and variable inductors can adjust to alter their inductance value.

B. Fixed value inductors can adjust to alter their inductance value and variable inductors

have a specific, unchanging value of inductance.

C. Fixed value inductors and variable inductors are the same.

Answer: A. Fixed value inductors have a specific, unchanging value of inductance and variable inductors can adjust to alter their inductance value.

3.4.2 Inductor Color Code

Question 1: What is the 4 band color code for a 10 microhenry (10µH) inductor with 5% tolerance?

A. Brown, black, brown, gold

B. Brown, black, black, gold

C. Brown, black, black, silver

D. Brown, black, green, gold

Answer: B. Brown, black, black, gold

Question 2: What is the 4 band color code for a 1 millihenry (1mH) inductor with 5% tolerance?

A. Brown, black, brown, gold

B. Brown, black, red, gold

C. Brown, black, black, silver

D. Brown, black, green, gold

Answer: B. Brown, black, red, gold

Question 3: What is the 4 band color code for a 100 microhenry (100µH) inductor with 5% tolerance?

A. Brown, black, green, gold

B. Brown, black, black, gold

C. Brown, black, black, silver

D. Brown, black, brown, gold

Answer: D. Brown, black, brown, gold

3.4.4 Inductor Value Conversion

Question 1: If an inductor has an inductance of 10 millihenry (10mH), what is its inductance in Henry (H)?

A. 0.01 H

B. 0.1 H

C. 1 H

D. 10 H

Answer: A. 0.01 H

Question 2: If an inductor has an inductance of 2.2 microhenry (2.2μH), what is its inductance in Henry (H)?

A. 2.2 × 10^-9 H

B. 2.2 × 10^-6 H

C. 2.2 × 10^-3 H

D. 2.2 × 10^-2 H

Answer: B. 2.2 × 10^-6 H

3.4.8 Inductors in Series

Question 1: What happens when we connect inductors in series?

A. The total inductance decreases.

B. The total inductance increases.

C. The total inductance remains the same.

Answer: B. The total inductance increases.

Question 2: Why might we want to connect inductors in series?

A. To decrease the total inductance.

B. To create a circuit with a specific total inductance.

C. To generate an electric field.

Answer: B. To create a circuit with a specific total inductance.

Question 3: What is the reason for connecting multiple inductors in series in a circuit that can handle high currents?

A. To generate a magnetic field around the circuit.

B. To generate an electric field around the circuit.

C. To distribute the current across them and reduce the risk of damage.

Answer: C. To distribute the current across them and reduce the risk of damage.

3.4.10 Inductors in Parallel

Question 1: What happens when inductors are connected in parallel?

A. The total inductance is always less than the value of the smallest inductance in the parallel circuit.

B. The total inductance is always greater than the value of the smallest inductance in the parallel circuit.

C. No change in total inductance.

Answer: A. The total inductance is always less than the value of the smallest inductance in the parallel circuit.

Question 2: Why is it easier for electrical current to travel through a circuit when inductors are connected in parallel?

A. Because the inductors become smaller when electrical current pass through them.

B. Because the inductors become bigger when electrical current pass through them.

C. Because the inductors share the load of the electrical current.

Answer: C. Because the inductors share the load of the electrical current.

Question 3: What is the analogy used in the text to explain inductors in parallel?

A. A group of people lifting a heavy object.

B. A bird flying in the sky.

C. A car driving on the road.

Answer: A. A group of people lifting a heavy object.

Question 4: What is the purpose of inductors connected in parallel in electronic devices?

A. To achieve required value of inductance.

B. To achieve required value of resistance of each inductor.

C. To increase value of inductance.

Answer: A. To achieve required value of inductance.

3.4.12 Variable Inductor

Question 1: What is a variable inductor?

A. An inductor we can adjust to have a different level of voltage.

B. An inductor we can adjust to have a different level of inductance.

C. An inductor we can adjust to have a different level of resistance.

Answer: B. An inductor we can adjust to have a different level of inductance.

Question 2: Why are variable inductors useful in electronic applications?

A. They can adjust the resistance of each inductor in a circuit.

B. They can adjust the DC voltage passing through each inductor in a circuit.

C. They can adjust the inductance where variation of inductance value is required.

Answer: C. They can adjust the inductance where variation of inductance value is required.

Question 3: What can be achieved by changing the inductance of a variable inductor in a circuit?

A. Controlling the amount of inductance.

B. Controlling the amount of DC voltage from power supply flowing into the inductor.

C. Controlling the amount of DC current from power supply flowing into the circuit.

Answer: A. Controlling the amount of inductance.

3.4.13 Transformers

Question 1: What is a transformer?

A. A device that helps us change the amount of voltage in an electrical circuit.

B. A device that helps us change the frequency of an electrical signal.

C. A device that helps us change the color of light bulbs.

Answer: A. A device that helps us change the amount of voltage in an electrical circuit.

Question 2: What is the primary coil?

A. The coil of wire that is connected to the power source.

B. The coil of wire that produces the output signal.

C. The coil of wire that converts the output signal.

Answer: A. The coil of wire that is connected to the power source.

Question 3: What is the secondary coil?

A. The coil of wire that is connected to the power source.

B. The coil of wire that produces the output.

C. The coil of wire that receives the electrical signal.

Answer: B. The coil of wire that produces the output.

Question 4: What is a step-up transformer?

A. A device that helps to reduce the voltage of an alternating current (AC) signal.

B. A device that helps to increase the voltage of an alternating current (AC) signal.

C. A device that helps to change the frequency of an electrical signal.

Answer: B. A device that helps to increase the voltage of an alternating current (AC) signal.

Question 5: What is a step-down transformer?

A. A device that helps to increase the voltage of an alternating current (AC) signal.

B. A device that helps to reduce the voltage of an alternating current (AC) signal.

C. A device that helps to change the color of light bulbs.

Answer: B. A device that helps to reduce the voltage of an alternating current (AC) signal.

3.5 Semiconductor Diodes

Question 1: What are diodes?

A. Electronic devices that allow current to flow in both directions.

B. Electronic devices that allow current to flow in only one direction.

C. Electronic devices that blocks electricity in both directions.

Answer: B. Electronic devices that allow current to flow in only one direction.

Question 2: What is a p-n junction?

A. A one-way valve for current flow.

B. A boundary layer between two regions with different electrical properties.

C. A device used to regulate voltage levels.

Answer: B. A boundary layer between two regions with different electrical properties.

Question 3: Who developed the first practical semiconductor diode?

A. Russell Ohl

B. Thomas Edison

C. Alexander Graham Bell

Answer: A. Russell Ohl

Question 4: What happens when a voltage applies in the correct direction to a diode?

A. The diode blocks the current flow.

B. The diode allows the current to flow in both directions.

C. The current flows easily through the diode.

Answer: C. The current flows easily through the diode.

3.5.1 Light Emitting Diode (LED)

Question 1: What is an LED?

A. A type of light bulb that uses gas to produce light.

B. A type of electronic component that produces light when electricity flows through it.

C. A type of device used to measure light.

Answer: B. A type of electronic component that produces light when electricity flows through it.

Question 2: How do LEDs differ from traditional light bulbs?

A. LEDs use gas to produce light while traditional bulbs use a filament.

B. LEDs use a filament to generate light while traditional bulbs use a semiconductor.

C. LEDs use a semiconductor to generate light while traditional bulbs use a filament or gas.

Answer: C. LEDs use a semiconductor to generate light while traditional bulbs use a filament or gas.

Question 3: Who invented the semiconductor laser diode?

A. Nick Holonyak Jr.

B. Oleg Vladimirovich Losev

C. Thomas Edison

Answer: A. Nick Holonyak Jr.

Question 4: What process do LEDs rely on to produce light?

A. Electromagnetic radiation

B. Electromagnetic waves

C. Electroluminescence

Answer: C. Electroluminescence

Question 5: What is the primary advantage of using LEDs in portable devices?

A. They are energy efficient.

B. They can create colorful displays.

C. They are very durable.

Answer: A. They are energy efficient.

3.5.2 Signal Diode

Question 1: What is a signal diode?

A. A type of diode used in electronic circuits to process small electrical currents or voltages carrying information.

B. A type of diode used to produce high electric currents in electronic devices.

C. A type of diode used in electronic circuits to rectify high electric currents.

Answer: A. A type of diode used in electronic circuits to process small electrical currents or voltages carrying information.

Question 2: Where are signal diodes commonly used?

A. In laptops to process operating system.

B. In radios, TVs, and other devices that receive signals from antennas or other sources.

C. In desktop to process digital signals.

Answer: B. In radios, TVs, and other devices that receive signals from antennas or other sources.

Question 3: How do signal diodes protect electronic devices?

A. By increasing the voltage that can pass through the circuit.

B. By multiplying the voltage that can pass through the circuit.

C. By limiting the voltage that can pass through the circuit.

Answer: C. By limiting the voltage that can pass through the circuit.

3.5.3 Power Diode

Question 1: What is the function of power diodes?

A. To multiply a large amount of electrical current without bursting.

B. To handle a significant amount of electricity without getting damaged.

C. To reduce the amount of electricity in a circuit.

Answer: B. To handle a significant amount of electricity without getting damaged.

Question 2: Where do we often use power diodes?

A. In power supply and electrical circuits that demand low power radio signal handling capabilities.

B. In power supply and electrical circuits that demand high power radio signal capabilities.

C. In power supply and electrical circuits that demand high power-handling capabilities.

Answer: C. In power supply and electrical circuits that demand high power-handling capabilities.

Question 3: How can we compare power diodes to a pipe?

A. Power diodes can handle a small amount of water without bursting.

B. Power diodes are similar to a small, fragile tube that cannot handle electricity.

C. Power diodes can handle a high volume of water without bursting.

Answer: C. Power diodes can handle a high volume of water without bursting.

3.6 Transistors

Question 1: What are transistors?

A. Type of passive component.

B. Type of component that rectify electronic signals.

C. Components that amplify or switch electronic signals.

D. Components that blocks electronic signals.

Answer: C. Components that amplify or switch electronic signals.

Question 2: How many layers do most common type of transistors have?

A. One layer.

B. Two layers.

C. Three layers.

D. Four layers.

Answer: C. Three layers.

Question 3: Why are the two p-n junctions created in most common type of transistors used for?

A. To fabricate easily by manufacturer without hassle.

B. To run the fabrication machines without stress.

C. To save electricity use by fabrication machines.

D. To create a base, emitter, and collector.

Answer: D. To create a base, emitter, and collector.

Question 4: What is the most common type of transistor?

A. Unipolar junction transistor.

B. Bipolar junction transistor.

C. Diode transistor.

D. Triode transistor.

Answer: B. Bipolar junction transistor.

Question 5: What happens when a small current flows into the base of a transistor?

A. It reverse the current flow direction between the emitter and collector.

B. It switches the current flow between the emitter and collector.

C. It controls a larger current flow between the emitter and collector.

D. It stops the current flow between the emitter and collector.

Answer: It controls a larger current flow between the emitter and collector.

3.6.1 Bipolar Junction Transistor (BJT)

Question 1: How many terminals does a bipolar junction transistor have?

A. One terminal.

B. Two terminals.

C. Three terminals.

D. Four terminals.

Answer: C. Three terminals.

Question 2: What can a BJT do in electronic circuits?

A. It can amplify signals

B. It can switch electronic signals.

C. Both A and B.

Answer: C. Both A and B.

Question 3: How can a small signal control a BJT?

A. By turning it into behaving like a power diode.

B. By allowing a larger current to flow through another part of the transistor.

C. By turning it into rectify electrical current.

Answer: B. By allowing a larger current to flow through another part of the transistor.

Question 4: How is a BJT useful in digital electronics?

A. By amplifying signals.

B. By turning things on and off.

C. By attenuating signals.

Answer: B. By turning things on and off.

PNP and NPN Types

Question 1: How many types of BJT are there?

A. Three

B. One

C. Two

Answer: C. Two

Question 2: What are the two types of BJT?

A. PNPN and NPNP

B. PNP and NPN

C. PNC and NCP

Answer: B. PNP and NPN

Question 3: What is the importance of paying close attention to the arrow mark direction in the symbol of PNP and NPN transistors?

A. To determine whether it represents a PNP or NPN transistor.

B. To determine the color of the transistor.

C. To determine the size of the transistor.

Answer: A. To determine whether it represents a PNP or NPN transistor.

Question 4: How many terminals do PNP and NPN transistors have?

A. Two

B. Three

C. Four

Answer: B. Three

Question 5: What are the terminals of PNP and NPN transistors?

A. A base, a collector, and a conductor.

B. A base, a conductor, and an emitter.

C. A base, a collector, and an emitter.

Answer: C. A base, a collector, and an emitter.

Question 6: What can a small amount of electricity applied to the base of PNP and NPN transistors do?

A. It can control the flow of a larger amount of current between the collector and the emitter.

B. It can turn off the entire function of transistor.

C. It can cause a short circuit.

Answer: A. It can control the flow of a larger amount of current between the collector and the emitter.

PNP transistor

Question 1: What happens when a small amount of electricity is applied to the base of a PNP transistor?

A. It rectifies the flow of AC voltage of collector.

B. It blocks the flow of AC voltage of emitter.

C. It affects the flow of current between the other two layers: the emitter and the collector.

Answer: C. it affects the flow of current between the other two layers: the emitter and the collector.

Question 2: How does a PNP transistor work as a switch?

A. By applying electricity to the collector.

B. By applying electricity to the emitter.

C. By applying electricity to the base.

Answer: C. By applying electricity to the base.

Question 3: What is the symbol for a PNP transistor?

A. An arrow pointing inward to the base terminals.

B. An arrow pointing outward from the base terminal.

C. A straight line connect between collector and emitter.

Answer: A. An arrow pointing inward to the base terminals.

Question 4: Which way does the current flow in a PNP transistor?

A. Only from the collector to the base.

B. From the collector to the emitter.

C. From the emitter to the collector.

Answer: C. From the emitter to the collector.

NPN transistor

Question 1: What happens when a small amount of electricity is applied to the base of an NPN transistor?

A. It allows a small current to flow between the collector and the emitter.

B. It allows a larger current to flow between the collector and the emitter.

C. It blocks current flow between the collector and the emitter.

Answer: B. It allows a larger current to flow between the collector and the emitter.

Question 2: What happens when a larger amount of current flows between the collector and the emitter in an NPN transistor?

A. It diverts more electrons to the base.

B. it allows less electrons flows between the collector and the emitter.

C. More electrons flows between the collector and the emitter.

Answer: C. More electrons flows between the collector and the emitter.

Question 3: What does an NPN transistor act like when electricity is applied to the base?

A. A switch.

B. A capacitor.

C. An inductor.

Answer: A. A switch.

Question 4: What does the symbol for an NPN transistor look like?

A. A semi-circle with an arrow pointing inwards.

B. An arrow pointing outward from the base terminal.

C. An arrow pointing inward towards the base terminal.

Answer: B. An arrow pointing outward from the base terminal.

Question 5: In which direction does the current flow in an NPN transistor?

A. From the collector to the emitter.

B. From the emitter to the collector.

C. Only from the collector to the base.

Answer: A. From the collector to the emitter.

3.7 Integrated Circuit (IC)

Question 1: Who are the co-inventors of the integrated circuit?

A. Thomas Edison and Alexander Graham Bell.

B. Jack Kilby and Robert Noyce.

C. Bill Gates and Steve Jobs.

D. Albert Einstein and Isaac Newton.

Answer: B. Jack Kilby and Robert Noyce.

Question 2: When was the first prototype IC developed?

A. 1958

B. 1960

C. 1959

D. 1961

Answer: A. 1958

Question 3: Why were electronic devices before ICs much bigger and more complex?

A. Because they required more power.

B. Because they required fewer components.

C. Because they required many components.

D. Because they were made of different materials.

Answer: C. Because they required many components.

Question 4: What is an IC?

A. A tiny electronic device that has many parts packed into a single piece of material.

B. A type of transistor.

C. A new type of diode.

D. A type of toy robot.

Answer: A. A tiny electronic device that has many parts packed into a single piece of material.

Question 5: What is the purpose of ICs?

A. To make electronic devices beautiful and stylish.

B. To make electronic devices smaller and more efficient.

C. To make electronic devices more expensive.

D. To make electronic devices bigger and colorful.

Answer: B. To make electronic devices smaller and more efficient.

Question 6: In which electronic devices are ICs used?

A. Only in computers.

B. Only in smartphones.

C. Only in remote control cars.

D. In many electronic devices that we use every day include computers, smart phones and remote control cars.

Answer: D. In many electronic devices that we use every day include computers, smart phones and remote control cars.

Question 7: What are some of the capabilities of an electronic micro-city made using ICs?

A. Aiding in data processing for computers and directing the locomotion of robots.

B. Only for aiding in data processing for computers

C. Only for directing the locomotion of robots.

D. Building micro-cities near metropolitans.

Answer: A. Aiding in data processing for computers and directing the locomotion of robots.

3.8 How to Identify and Read the Value of Components

Question 1: What is the first step to read the value of components in electronics?

A. Determine what the component is by examining it.

B. Read the markings on the component.

C. Verify your readings using a multimeter.

Answer: A. Determine what the component is by examining it.

Question 2: How can you identify the value of a 4 band resistor?

A. By the unit of measurement printed on it.

B. By the numerical value printed on it.

C. By the colored bands on it.

Answer: C. By the colored bands on it.

Question 3: How can you interpret the markings on a capacitor?

A. By using a color code chart.

B. By matching the numerical value to specific units.

C. By checking the tolerance rating.

Answer: B. By matching the numerical value to specific units.

Question 4: What does tolerance rating show?

A. How much the actual value of the component may differ from the stated value.

B. The numerical value of the component.

C. The temperature tolerance of component.

Answer: A. How much the actual value of the component may differ from the stated value.

Question 5: Why is it important to verify your readings using a measuring device?

A. To identify the component.

B. To ensure that the component is functioning as expected.

C. To interpret the markings on the component.

Answer: B. To ensure that the component is functioning as expected.

Chapter 4

Electronic Tools and Equipment

We can use electronic tools and equipment to create, change, or measure electronic signals and circuits.

Electronic hobbyists, engineers, and technicians use these tools to build electronic circuits, troubleshoot and repair electronic devices, and test electronic components.

Some of the commonly used electronic tools include:

Multimeter: This device measures electrical voltage, current, and resistance.

Oscilloscope: This tool measures and displays electrical signals.

Soldering iron: It is a tool used to solder components onto a printed circuit board.

Breadboard: This tool allows for creating for creating for creating and testing electronic circuits without soldering.

Power supply: This device provides electrical power to electronic circuits.

Wire cutters and strippers: These tools are used to cut and strip electrical wires.

Logic probe: This device tests and troubleshoots digital logic circuits.

Kids can develop a better understanding of how electronic devices work and how they made by using these tools.

They can also develop important skills, such as problem-solving, critical thinking, and attention to detail.

With proper guidance and supervision, electronic tools and equipment can offer a fun and rewarding way for kids to learn about electronics.

4.1 Multimeter

A multimeter is an electronic device used to measure various electrical quantities, including voltage, current, and resistance.

It is an essential tool for electronics engineers, electricians, and hobbyists alike.

A multimeter typically has several functions, including measuring AC and DC voltage, current, and resistance, as well as testing diodes, continuity, and capacitance.

To use a multimeter, you need to set it to the function and range.

For example, if you want to measure the voltage of a battery, you would set the multimeter to DC voltage mode and select the range.

You would then connect the multimeter leads to the battery terminals, taking care to connect the red lead to the positive terminal and the black lead to the negative terminal.

The multimeter would then display the voltage reading on its screen.

4.2 Breadboard

A breadboard is a device used to prototype electronic circuits with no soldering.

It comprises a plastic board with a grid of holes, into which components and wires can insert.

Orville Thompson of the DeVry Technical Institute patented a solderless breadboard in 1960 that connected rows of holes together with spring metal.

On August 14, 1973 an engineer named Ronald Portugal patented a similar concept with holes spaced at 0.1 inches (2.54 mm), which was the same as DIP IC packages.

This concept became the basis for the modern solderless breadboard that is widely used today. The patent granted and expired in 1987.

Breadboards are an essential tool for electronics hobbyists and students who want to experiment with circuits with no permanent soldered connection.

To use a breadboard, you should initially position your components on the board and then connect those using wires.

You can then test your circuit by applying power to it and observing its behavior. Breadboards are versatile and can use for a wide range of circuits, from simple LED blinkers to complex microcontroller projects.

4.3 Soldering Iron

A soldering iron is a tool used to melt solder, a metal alloy used to join two metal surfaces.

We commonly used soldering irons in electronics and plumbing to create permanent connections between wires, components, and pipes.

To use a soldering iron, you first heat it up to the temperature for the solder you are using.

We should place the soldering iron tip on the joint. Apply a small amount of solder to the joint.

The heat from the soldering iron melts the solder, which flows into the joint and creates a strong, permanent bond.

4.4 Oscilloscope

An oscilloscope is an electronic device used to measure and display electrical signals.

We commonly used oscilloscope in electronics and engineering to analyze and debug circuits, as well as to test and measure the performance of electronic devices.

To use an oscilloscope, you first connect its probes to the circuit or device you want to measure.

You can adjust oscilloscope's settings, such as time-base and voltage scale, to display the signal in the way you want.

The oscilloscope displays the signal as a waveform on its screen, allowing you to analyze its frequency, amplitude, and other characteristics.

4.5 DC Power Supply

A DC power supply is a device that provides a continuous flow of electrical energy to power electronic devices.

It converts AC (alternating current) electricity from a wall outlet or battery into DC (direct current) electricity, which is used to power most electronic devices like phones, computers, and toys.

Think of it like a water pipe: AC electricity is like water flowing back and forth in a pipe, while DC electricity is like a steady flow of water in one direction.

The DC power supply takes the back-and-forth flow of AC electricity and converts it into a steady stream of DC electricity, which can power electronic devices.

There are different DC power supplies, but some common ones include wall adapters, which plug into an electrical outlet and have a cord that connects to the device, and batteries, which provide DC power directly to the device.

4.5.1 Cell and Battery

Cell and battery are portable power sources that store chemical energy and convert it into electrical energy.

Cell

A chemical reaction generates electrical energy in a unit known as a cell, which comprises two electrodes - a positive electrode (anode) and a negative electrode (cathode) - immersed in an electrolyte solution.

When a conductor, such as a wire, connects the electrodes, electrons flow from the negative electrode to the positive electrode, producing an electrical current.

Examples of cells include alkaline, Lithium, and Zinc-Carbon cells.

Battery

A battery comprises two or more connected cells.

When we connect cells in series, the positive electrode of one cell links to the negative electrode of the next cell, forming a chain of cells.

When we connect cells in parallel, the positive electrodes of all cells join, and the negative electrodes of all cells unite, creating a unit with a longer life or higher capacity than a single cell.

Both cells and battery come in different shapes and sizes, and they can be primary or rechargeable.

We use once primary cells and batteries and then discarded, while rechargeable can recharge and used again.

Common types of battery include alkaline, lithium-ion, nickel-cadmium, and lead-acid batteries.

We widely use cells and batteries in electronic devices, such as cell phones, laptops, cameras, and remote controls.

4.5.2 AC/DC adapters

AC/DC adapters are power supplies that convert AC voltage from a wall outlet to DC voltage that electronic devices can use.

Power adapters, AC adapters, or wall warts are alternative names for AC/DC adapters.

They come in different shapes and sizes, and they can have different output voltages and currents.

Some common types of AC/DC adapters include linear power supplies, switching power supplies, and USB chargers.

AC/DC adapters we use in a wide range of electronic devices, such as laptops, routers, printers, and game consoles.

The major difference between batteries and AC/DC adapters is that batteries are self-contained power sources, while AC/DC adapters require an external power source, such as a wall outlet.

We can use batteries in portable devices, where AC/DC adapters are not practical. AC/DC adapters are more reliable and can provide more power than batteries.

AC/DC adapters can also power multiple devices at once, whereas batteries are not sufficient in order to power one device at a time.

Multiple Choice Questions and Answers

Chapter 4

Electronic Tools and Equipment

Question 1: What is the purpose of electronic tools and equipment?

A. To create and measure electronic signals and circuits.

B. To build mechanical parts for the circuits.

C. To measure dimensions of the circuit.

Answer: A. To create and measure electronic signals and circuits.

Question 2: Who uses electronic tools to build and repair electronic devices?

A. Only electronic engineers can use.

B. Only electronic technicians can use.

B. Electronic hobbyists, engineers, and technicians.

Answer: B. Electronic hobbyists, engineers, and technicians.

Question 3: Which tool allows for creating and testing electronic circuits without soldering?

A. Multimeter

B. Oscilloscope

C. Breadboard

Answer: C. Breadboard

Question 4: What skills can kids and absolute beginners develop by using electronic tools and equipment?

A. Reading and writing electronic notes.

B. Problem-solving, critical thinking, and attention to detail.

C. Reading schematics.

Answer: B. Problem-solving, critical thinking, and attention to detail.

Question 5: What can electronic tools and equipment offer kids and absolute beginners?

A. A hard way to learn about electronics.

B. A fun and rewarding way to learn about electronics.

C. A confusing way to learn about electronics.

Answer: B. A fun and rewarding way to learn about electronics.

4.1 Multimeter

Question 1: What is the purpose of a multimeter?

A. To measure the weight of an electronic device.

B. To measure electrical voltage, current, and resistance.

C. To measure dimensions of an electronic device..

Answer: B. To measure electrical voltage, current, and resistance.

Question 2: Who uses a multimeter?

A. Only electricians can use.

B. Electronics engineers, electricians, and hobbyists can use.

C. Only hobbyists can use.

Answer: B. Electronics engineers, electricians, and hobbyists can use.

Question 3: What functions does a multimeter typically have?

A. Measuring DC voltage.

B. Measuring AC current.

C. Measuring AC and DC voltage, current, and resistance, as well as testing diodes, continuity, and capacitance.

Answer: C. Measuring AC and DC voltage, current, and resistance, as well as testing diodes, continuity, and capacitance.

Question 4: How do you use a multimeter to measure the voltage of a battery?

A. Set the multimeter to AC voltage mode.

B. Set the multimeter to continuity mode.

C. Set the multimeter to DC voltage mode and select the range, then connect the red lead to the positive terminal and the black lead to the negative terminal.

Answer: C. Set the multimeter to DC voltage mode and select the range, then connect the red lead to the positive terminal and the black lead to the negative terminal.

Question 5: What will the multimeter display when measuring the voltage of a battery?

A. AC voltage reading of the battery.

B. DC voltage reading of the battery.

C. Continuity of the battery.

Answer: B. DC voltage reading of the battery.

4.2 Breadboard

Question 1: What is a breadboard used for?

A. To prototype electronic circuits with soldering.

B. To prototype electronic circuits without soldering.

C. To prototype electronic circuits with both soldering and without soldering.

Answer: B. To prototype electronic circuits without soldering.

Question 2: Who patented the solderless breadboard in 1960?

A. Ronald Portugal

B. Orville Thompson

C. Thomas Edison

Answer: B. Orville Thompson

Question 3: What is the grid of holes in a breadboard used for?

A. To decorate the board.

B. To connect the components and wires.

C. To make breadboard look cool.

Answer: B. To connect the components and wires.

Question 4: When was the modern solderless breadboard based on Ronald Portugal's concept patented?

A. 1960

B. 1973

C. 1987

Answer: B. 1973

Question 5: What is the advantage of using a breadboard for experimenting with circuits?

A. It makes the circuits look cool.

B. It allows you to test circuits without permanent soldered connections.

C. It makes the circuits smaller.

Answer: B. It allows you to test circuits without permanent soldered connections.

Question 6: What kind of circuits can be used with a breadboard?

A. Only simple circuits.

B. Only complex microcontroller projects.

C. A wide range of circuits.

Answer: C. A wide range of circuits.

4.3 Soldering Iron

Question 1: What is a soldering iron used for?

A. To melt component pins.

B. To join two metal surfaces.

C. To cut electric wires.

D. To cut metal surfaces.

Answer: B. To join two metal surfaces.

Question 2: In what fields are soldering irons commonly used?

A. Only in electronics.

B. Only in electrical.

C. Both in electronics and electrical.

D. In metal workshops.

Answer: C. Both in electronics and electrical.

Question 3: What should we do before using a soldering iron?

A. Apply oil to the tip.

B. Clean the tip with water.

C. Heat it up to the temperature for the solder we are using.

D. Leave it in the open air.

Answer: C. Heat it up to the temperature for the solder we are using.

Question 4: Where should we place the soldering iron tip when soldering?

A. On the joint.

B. Only one side of the joint.

C. Beneath the joint.

D. On right side of the joint.

Answer: A. On the joint.

Question 5: What happens when the heat from the soldering iron melts the solder?

A. The solder becomes harder.

B. The solder evaporates.

C. The solder melts and flows into the joint and creates a strong, permanent bond.

D. The solder turns into a gas.

Answer: C. The solder melts and flows into the joint and creates a strong, permanent bond.

4.4 Oscilloscope

Question 1: What is an oscilloscope used for?

A. To measure and display electrical signals.

B. To measure the temperature of electronic devices.

C. To measure the weight of electronic devices.

Answer: A. To measure and display electrical signals.

Question 2: Where is an oscilloscope commonly used?

A. In mechanical engineering field.

B. In civil engineering field.

C. In electronics and electrical engineering fields.

Answer: C. In electronics and electrical engineering fields.

Question 3: How do you use an oscilloscope for measurement?

A. Connect its probes to the circuit or device you want to measure.

B. Connect its probes to the chassis of an electronic device under test.

C. Connect its probes to a power source of an electronic device under test.

Answer: A. Connect its probes to the circuit or device you want to measure.

Question 4: What can you adjust on an oscilloscope?

A. Time-base and voltage scale.

B. Temperature of oscilloscope in degree Celsius.

C. Temperature of oscilloscope in Fahrenheit.

Answer: A. Time-base and voltage scale.

Question 5: How does an oscilloscope display the signal?

A. As a number.

B. As a picture.

C. As a waveform on its screen.

Answer: C. As a waveform on its screen.

Question 6: What characteristics can you analyze using an oscilloscope?

A. Weight and size.

B. Frequency, amplitude, time, and others.

C. Temperature and pressure.

Answer: B. Frequency, amplitude, time, and others.

4.5 DC Power Supply

Question 1: What does a DC power supply do?

A. Provides a continuous flow of electrical energy to power electronic devices.

B. Provides an alternating flow of electrical energy to power electronic devices.

C. Provides both alternating and continuous flow of electrical energy to power electronic devices.

Answer: A. Provides a continuous flow of electrical energy to power electronic devices.

Question 2: What kind of electricity does a DC power supply convert?

A. Alternating current (AC) electricity.

B. Direct current (DC) electricity.

C. Both AC and DC electricity.

Answer: B. Direct current (DC) electricity.

Question 3: How is DC electricity different from AC electricity?

A. DC electricity flows back and forth in a wire, while AC electricity flows in one direction.

B. DC electricity is a steady flow of electricity in one direction, while AC electricity flows back and forth.

C. DC electricity and AC electricity are the same.

Answer: B. DC electricity is a steady flow of electricity in one direction, while AC electricity flows back and forth.

Question 4: What are some common types of DC power supplies?

A. Wall adapters and batteries.

B. Windmill.

C. Hydroelectric generators.

Answer: A. Wall adapters and batteries.

Question 5: How does a wall adapter connect to a device?

A. It has a cord that connects to the device.

B. It is fixed inside the wall of the building and device should connect to the wall.

C. It connects wirelessly to the device.

Answer: A. It has a cord that connects to the device.

4.5.1 Cell and Battery

Question 1: What is a cell?

A. A portable power source that converts electrical energy into chemical energy.

B. A portable power source that stores chemical energy and converts it into electrical energy.

C. A device that connects cells in series to form a chain of cells.

Answer: B. A portable power source that stores chemical energy and converts it into electrical energy.

Question 2: What are the two electrodes in a cell?

A. Cell has two positive electrodes.

B. Positive electrode (cathode) and negative electrode (anode)

C. Positive electrode (anode) and negative electrode (cathode).

Answer: C. Positive electrode (anode) and negative electrode (cathode).

Question 3: How does an electrical current flow in a cell?

A. Electrons flow from the positive electrode to the negative electrode.

B. Electrons flow from the negative electrode to the positive electrode.

C. Electrons do not flow in a cell.

Answer: B. Electrons flow from the negative electrode to the positive electrode.

Question 4: What is a battery?

A. A single cell connected in series with circuit.

B. A single cell connected in parallel with circuit.

C. Two or more connected cells.

Answer: C. Two or more connected cells.

Question 5: How is series connection of cells formed in a battery?

A. By connecting the positive electrode of one cell to the negative electrode of the next cell.

B. By connecting the negative electrode of a cell to the positive electrode of the same cell.

C. Not possible to connect cells in series.

Answer: A. By connecting the positive electrode of one cell to the negative electrode of the next cell.

Question 6: What is the difference between a primary and a rechargeable cell or battery?

A. Primary cells and batteries can be recharged, while rechargeable cells and batteries cannot be recharged.

B. Primary cells and batteries can only be used once, while rechargeable cells and batteries can be recharged and used again.

C. Primary cells and batteries have a longer life than rechargeable cells and batteries.

Answer: B. Primary cells and batteries can only be used once, while rechargeable cells and batteries can be recharged and used again.

Question 7: What are types of batteries?

A. Alkaline, nickel-cadmium, lead-acid, lithium, and zinc-carbon batteries.

B. Iron-copper, aluminum-steel, and gold-brass batteries.

C. Uranium-nickel, plutonium-copper, and tantalum-iron batteries.

Answer: A. Alkaline, nickel-cadmium, lead-acid, lithium, and zinc-carbon batteries.

4.5.2 AC/DC Adapters

Question 1: What is an AC/DC adapter?

A. A device that converts DC voltage to AC voltage.

B. A device that converts AC voltage from a wall outlet to DC voltage that electronic devices can use.

C. A type of battery that provides power to electronic devices.

Answer: B. A device that converts AC voltage from a wall outlet to DC voltage that electronic devices can use.

Question 2: What are some alternative names for AC/DC adapters?

A. Power sources and batteries.

B. Power adapters, AC adapters, and wall warts.

C. Switching power supplies and linear power supplies.

Answer: B. Power adapters, AC adapters, and wall warts.

Question 3: What are some common types of AC/DC adapters?

A. Rechargeable batteries and USB chargers.

B. Linear power supplies and switching power supplies.

C. Solar panel based cell chargers and windmill based cell chargers.

Answer: B. Linear power supplies and switching power supplies.

Question 4: What electronic devices can use AC/DC adapters?

A. Televisions and refrigerators.

B. Laptops, routers, printers, and game consoles.

C. Wired mouse and wired keyboards.

Answer: B. Laptops, routers, printers, and game consoles.

Question 5: What is the main difference between batteries and AC/DC adapters?

A. Batteries are more reliable than AC/DC adapters.

B. AC/DC adapters are self-contained power sources, while batteries require an external power source.

C. AC/DC adapters require an external power source while batteries are self-contained power sources.

Answer: C. AC/DC adapters require an external power source while batteries are self-contained power sources.

Question 6: Why are batteries more practical for portable devices?

A. Because they are more reliable than AC/DC adapters.

B. Because they provide more power than AC/DC adapters.

C. Because AC/DC adapters require an external power source, such as a wall outlet.

Answer: C. Because AC/DC adapters require an external power source, such as a wall outlet.

Question 7: Can AC/DC adapters power multiple devices at once?

A. Yes, they can.

B. No, they cannot.

C. It depends on the type of AC/DC adapter and type of connected load.

Answer: C. It depends on the type of AC/DC adapter and type of connected load.

Chapter 5

Understanding Circuit/Schematic Diagrams

5.1 Name Designators and Values

Being able to recognize components is the key to being schematic-literate. Even though the component symbols tell half of the story, the name and value of each symbol complete it.

5.2 Names and Values

In schematic components like resistors, capacitors, and inductors, the value specifies the quantity of Ohm, Farad, Henry etc.

We list the oscillating frequency as the value for crystals. The name of the chip may also serve as its value. A schematic component’s most important characteristic is called out by its value, which helps define it.

The letter part of the component name identifies the type of component, such as R for resistors, C for capacitors, and U for integrated circuits.

Component names should be unique in a schematic. If there are three resistors in a circuit, resistors should name R1, R2, and R3. Component names assist us in referring to specific points on schematics.

The prefixes of names “standardized”. The prefix for certain components is the first letter of the component’s name.

Other name prefixes are not as straightforward, such as inductors, which are designated as L (since we have already taken).

Here is a brief table of common components and their name prefixes:

Even though the standardized names for component symbols exist, some people are not follow them.

For instance, some might prefix integrated circuits with IC instead of U, or label crystals as XTAL’s instead of Y’s.

Therefore, use your best judgment in diagnosing which part is which the symbol should provide enough information.

5.3 Circuit Diagram Connections

The image below shows how circuit diagrams or schematic diagrams use nodes, which are simply filled circles or dots, to illustrate the electrical connections of wires or conductors.

When three or more lines touch or cross each other, we place a node at the intersection to represent the electrical connection of the lines or wires at that point.

The wires/lines at the bottom of the above image do not have an electrical connection as they cross each other without a node.

Here, the wires cross each other without being connected.

5.4 Example Circuit Diagram

5.5 Some of Circuit Diagram Rules

General circuit diagram rules dictate:

-You can use horizontal or vertical lines to represent wires or lines in circuit diagrams. You may use a diagonal line at a 45-degree angle sometimes.

-Place component symbols horizontal or vertical in circuit diagrams. Place them 45-degree angle if there is an excellent reason to do so.

-Draw circuit diagrams keeping in mind that the physical implementation of the circuit may appear different while remaining identical.

-Assume that lines connecting components are “insulated” wires in most cases, with only the ends of the wires being bare conductors for electrical connection.

-Consider two insulated wires crossing each other in a circuit diagram as connected. If they do not intersect or cross each other at a node, even if their lines cross each other.

-Treat three wires at a point where they intersect and have a node as “electrically” connected. Treat this connection as three insulated wires bared at the intersection point and soldered together.

-Consider two wires crossing each other with a node at the intersection as “electrically” connected.

Chapter 6

Understanding Breadboard

A breadboard (solder-less breadboard), or prototype board, is a baseboard for prototyping of electronic circuits.

Solder-less breadboards do not require soldering, and they are reusable, and we can assemble components and dismantle with ease.

A breadboard is easy to use for constructing temporary prototypes and experimenting on a circuit design, and breadboards are popular with electronic hobbyists, students and circuit designers.

6.1 Why to Build on a Breadboard?

- Suitable for simple electronic circuit assembly.

- Quicker and easier connections of components, and no soldering is required.

- Possible to change component connections quickly without damages, and this allows modification of the circuit.

- Possible to interchange/replace components quickly.

- Easy to dismantle the components.

- We can reuse a Breadboard for different circuit assembly.

The current handling capacity of the breadboard has limits and is best used for developing a prototype before developing the actual PCB.

A prototype allows testing of a circuit design before proceeding to the fabrication of the printed circuit board (PCB).

6.2 Breadboard Structure

Breadboard consists circuit assembly area and power rail, and the circuit assembly area is nothing but a matrix of holes.

The holes on the breadboard refer as Points, an 830 point breadboard means 830 holes on the breadboard.

You can notice that the circuit area on the breadboard divides into two sections. The first section is rows A to E and the second section is rows F to J.

A channel runs between two rows, which allows the insertion of Dual In-Line (DIP/DIL) package integrated circuit (IC), and terminals on the breadboard.

Each vertical column comprises 5 holes, and we number each column starting from number 1.

Refer to the image below, we highlight vertical columns in green color. Each column comprises five holes which are INTERNAL CONNECT beneath the breadboard.

The power rail on the breadboard comprises four rows of holes, and all the holes in a row are INTERNAL CONNECT beneath the breadboard.

Two rows highlighted in red color are for positive of power supply connection, and two rows highlighted in black color are for negative of power supply connection.

6.3 Types of Breadboard Connecting Wires

We can use two types of wires for breadboard wiring, the first is ready-made jumpers, and the second is hook-up (single-strand) wire.

The jumpers are available in different colors and length of wires, and 3 combination of end pins (also referred as terminal pins).

The jumper wire is available in different terminal pin combinations, such as male-to-male, male-to-female, and female-to-female.

6.4 Breadboard Power Supply

There are many ways to power up a breadboard, and the power supply requirement is depending on the circuit built on a breadboard.

Most commonly using power supply for the breadboard are batteries and dedicated power supply module/board.

The power supply module/board supplies outputs DC 3.3 Volts and DC 5 Volts, and we can select using a switch on the module.

We can also get DC 5 Volts output from the module/board with the on board (built-in) USB port.

We can connect buses on opposite sides of the breadboard to each other to ensure power and ground are available on both sides of the breadboard.

We can connect the buses using jumper wires as shown in the image below.

6.5 Placing Components on a Breadboard

There are different ways to place components on a breadboard, depending on the component type, and the following images illustrate different component placed on a breadboard.

NOTE: In the images below, for illustration we showed holes with a green color border connected inside, beneath the breadboard.

After you insert the component, the component pin connects with the other 4 holes in the row (4 holes with a green color border).

Chapter 7

Build a Practice Circuit on a Breadboard

This tutorial shows you how to build a very simple circuit which lights up a single Light-Emitting Diode (LED).

You will learn:

- About resistors

- About LEDs

- How to read a circuit diagram

- How to build a circuit.

Parts Required:

- 1x Resistor 1k (brown black red gold)

- 1x LED (Light-Emitting Diode)

- 1x Breadboard

- 1x Set of breadboard connecting/link wires

- 1x 9V Battery

- 1x battery snap/link for 9V battery

7.1 Reading the Circuit Diagram

The example circuit diagram (also known as a schematic diagram) is shown below.

The circuit diagram instructs us to connect the 1 kilo-ohm resistor’s pin (lead) to positive terminal of the battery.

The other pin of the 1 kilo-ohm resistor connects to anode terminal of the Light-Emitting Diode (LED).

We should connect the cathode terminal of the LED to the negative terminal of the battery.

In circuit diagrams where the battery or power source is not visible, a textual representation shows (9V or 9 Volts) the voltage that needs to be connected across the circuit.

The alternate circuit shown in this diagram follows this convention.

7.2 Building the Circuit

Get the parts and tools ready:

Step 1: Bend the longer lead of the LED.

Insert the longer lead (anode) of the LED into the red line marked top rail (battery positive) of the breadboard and place the other lead into a hole in the main part of the breadboard, as shown. This completes step 1 of the process.

Step 2: Insert the Resistor into the Breadboard

To remove a 1k resistor from a string of resistors that are taped together, use the side cutters to cut the resistor lead as close to the tape as possible.

If you remove the tape, there will be a mess on the board.

Then, bend the leads of the resistor. Insert one of the resistor leads into a hole directly below the cathode lead of the LED, and inserts the other lead into a hole below the middle channel of the breadboard.

This will connect the LED cathode to one of the resistor leads. It does not matter which way we plug the resistor into the breadboard.

Step 3: Insert the Wire Link into the Breadboard

Insert the wire connector directly below the resistor lead into the black line marked bottom rail (battery negative) of the breadboard.

Step 4: Insert the Battery Clip into the Breadboard

Insert the red (positive) wire of the battery clip into the top rail (red line) of the breadboard. Insert the black (negative) wire of the battery clip into the bottom rail (black line) of the breadboard.

Step 5: Plug the Battery into the Battery Clip

You plug the battery into the battery clip to power up the circuit and switch on the LED. Connect the battery clip to the battery, ensure that you connect the battery in the correct way on the first attempt.

Chapter 8

DIY Electronic Projects

You can learn about electronics by doing DIY electronic projects.

In electronics, DIY (Do-It-Yourself) projects are a great way for you to learn about electronics.

By building their own projects, you can learn about circuits, electronic components, programming, and more.

Some popular DIY electronic projects for you include building a simple LED circuit, creating a music alarm, control a motor, use light, sound and temperature to create projects.

DIY electronic projects can help you develop critical thinking, problem-solving, and analytical skills, as you work through the design and building process.

These projects can also spark creativity and foster a love of science and engineering in young minds.

DIY electronic projects provide a hands-on and engaging way for you to learn about electronics and technology.

LED Projects

You can learn a lot about electronics with the help of Light-Emitting Diodes circuits.

When the circuit is done, we turn on the power. LED light up.

You can experiment with different LEDs, resistors, and power sources to create different LED circuits and learn more about how they work.

8.1 Power-up Two LEDs Project

This project is two LEDs circuit, and it is a basic electronic project that involves using two LEDs to produce light. The circuit typically comprises two LEDs and a resistor connected in series, and a 9 volts battery.

-Two LEDs: This is the component that produces the light. LED come in different colors and sizes. In this project, we are using each of red and green color 5mm diameter round LED.

-A resistor: This component limits the amount of current that flows through the LED, protecting it from damage. In this project, we are using a 270Ω resistor with ±5 tolerance.

-A power source: This can be a 9 Volts battery or a DC power supply.

Refer to the schematic diagram for connections.

8.1.1 Schematic Diagram of Power-up Two LEDs Project

8.1.2 Parts List

1x Breadboard 830 points

1x Set of breadboard jumper wires or hook-up wires

1x Wire Cutter/stripper

1x Battery 9-volt

1x Snaps for 9-volt battery

1x Resistor 270Ω (red violet brown gold) ±5% tolerance, 1/4 Watt

2x Light-Emitting Diode (LED) Red color 5mm diameter

8.1.3 Pin Configurations

8.1.4 Breadboard Wiring Diagram of Power-up Two LEDs Project

Transistor Project

An electronic project using a transistor is a fun and exciting way for you to explore the world of electronics.

You can create your own cool project by using a transistor and in your electronic projects.

You can learn how to control the flow of electricity and make things do what you want them to do.

You will learn how to put the parts together and make the transistor work, which is a really cool thing to do!

8.2 Simple Water Level Indicator Project

The Simple Water Level Indicator circuit is an electronic circuit that we can use to detect the water level in a container.

The circuit contains a BC547 transistor, a 5 Volts buzzer, a 1k resistor, a 9-volt battery, and a glass of water.

To create the circuit, start by connecting the base of the BC547 transistor to the 1k resistor.

You use another end of the 1k resistor with a piece of wire to act as a first probe to immerse in a water glass.

You connect another piece of wire to the positive terminal of the battery as a second probe to immerse in a water glass.

Next, connect the collector of the transistor to the negative terminal of the buzzer and connect the positive terminal of the buzzer to the positive terminal of the battery.

You should adjust the position of two probes as shown in the schematic diagram.

Finally, connect the emitter of the transistor to the negative terminal of the battery.

Now you add water into the glass. When the water level in the glass is below a certain point, the transistor will not conduct and the buzzer will remain silent.

However, when the water level in the glass rises, two probes come into electric contact and current flows into the base of the transistor.

BC547 transistor will conduct and allow current to flow from the collector to the emitter, causing the buzzer to sound.

8.2.1 Schematic Diagram of Simple Water Level Indicator Project

8.2.2 Parts List

1x Breadboard 830 points

1x Set of breadboard jumper wires or hook-up wires

1x Wire Cutter/stripper

1x Battery 9-volt

1x Snaps for 9-volt battery

1x Resistor 1kΩ (brown black red gold) ±5% tolerance, 1/4 Watt

1x Buzzer (5 volts)

1x Transistor BC547

1x Water glass or tumbler or any non-metallic container

8.2.3 Pin Configurations

8.2.4 Breadboard Wiring Diagram of Simple Water Level Indicator Project

8.3 Make Transistor as a Switch Project

We can use NPN transistors as a switch to turn on and off electronic circuits. An NPN transistor comprises three parts - the base, the collector, and the emitter.

The transistor allows a larger voltage to flow from the collector to the emitter terminal when a small voltage applies to the base.

Integrating the NPN transistor into a circuit with the desired load that needs to be controlled allows for regulating the load on/off state by applying voltage to its base.

The load is something you wish to turn on or off, and by integrating the NPN transistor, you can actively manage its state.

So, instead of using a physical switch to turn something on and off, you can use an NPN transistor as a switch in your electronic circuits!

8.3.1 Schematic Diagram of Make Transistor as a Switch Project

8.3.2 Parts List

1x Breadboard 830 points

1x Set of breadboard jumper wires or hook-up wires

1x Wire Cutter/stripper

1x Battery 9-volt

1x Snap sfor 9-volt battery

1x Resistor 330Ω (orange orange brown gold) ±5% tolerance, 1/4 Watt

1x Resistor 1kΩ (brown black red gold) ±5% tolerance, 1/4 Watt

1x Resistor 10kΩ (brown black orange gold) ±5% tolerance, 1/4 Watt

1x Light-Emitting Diode (LED) Red color

1x Transistor 2N2222

1x SPST Switch toggle type

8.3.3 Pin Configurations

8.3.4 Breadboard Wiring Diagram of Make Transistor as a Switch Project

Sensor Projects

In electronics, a sensor is a device that detects and responds to physical or chemical stimuli, such as light, temperature, pressure, motion etc.

Sensors are used to convert these stimuli into measurable electrical signals that electronic circuits or computer systems can process.

They are essential components in a wide range of applications, including automotive systems, medical devices, industrial automation, and consumer electronics.

Some common types of sensors include temperature sensors, pressure sensors, proximity sensors, and motion sensors.

8.4 Build a Light Sensor Project

A light sensor circuit is an electronic project that uses a photo resistor or photodiode to detect changes in light levels.

When the light level changes, the resistance of the sensor changes, which can trigger an alarm or activate a device.

We commonly use light sensor circuits in security systems and automatic lighting systems.

8.4.1 Schematic Diagram of Light Sensor Project

8.4.2 Parts List

1x Breadboard 830 points

1x Set of breadboard jumper wires or hook-up wires

1x Set of wire with double end Alligator (Crocodile) clips

1x Wire Cutter/stripper

1x Battery 9-volt

1x Snaps for 9-volt battery

1x Resistor 330Ω (orange orange brown gold) ±5% tolerance, 1/4 Watt

1x Resistor 1kΩ (brown black red gold) ±5% tolerance, 1/4 Watt

1x Potentiometer (POT) 4k7Ω (4.7 kilo ohms), linear type

1x Knob for potentiometer

1x Light-Emitting Diode (LED) red color

1x Light Dependent Resistor (LDR)

1x Transistor BC547

8.4.3 Pin Configurations

8.4.4 Breadboard Wiring Diagram of Light Sensor Project

8.5 Build a Temperature Sensor Project

A temperature sensor circuit is an electronic project that uses a thermistor or temperature sensor to detect changes in temperature.

The circuit can control heating and cooling systems or to monitor the temperature in a particular area.

Temperature sensor circuits can be simple or complex, depending on the application.

To explain how the circuit works, we look at the components involved:

BC547 transistor: The transistor acts as a switch in this circuit. When a small current applies to its base, it allows a larger current to flow from the collector to the emitter.

10k NTC thermistor: The thermistor is a type of resistor whose resistance changes with temperature. In this circuit, an NTC thermistor is used to sense the temperature and control the behaviour of the circuit.

1k potentiometer: The potentiometer is a variable resistor that can adjust the amount of current flowing through it.

LED: The LED (Light-Emitting Diode) is a type of diode that emits light when current flows through it in the forward direction.

9-volt battery: The battery provides the power to the circuit.

1k base resistor: The base resistor is used to limit the current flowing into the base of the transistor.

Buzzer: The buzzer is a type of transducer that converts electrical energy into sound.

Let’s look at how these components work together in the circuit:

When the circuit is power on, current flows from the positive terminal of the battery through the 10k NTC thermistor, the potentiometer, and the 1k base resistor into the base of the BC547 transistor.

Resistance of the NTC thermistor changes with the temperature, which affects the current flowing into the base of the transistor.

The potentiometer is used to adjust the sensitivity of the circuit.

If the temperature is below a certain threshold, the transistor is in a non-conducting state, and the LED is off.

However, when the temperature rises above the threshold, the resistance of the NTC thermistor decreases, allowing more current to flow into the base of the transistor.

This causes the transistor to switch on, allowing the current to flow from the collector to the emitter and this current flows through the LED, which turns on, and through the buzzer, which sounds.

Potentiometer can adjust the sensitivity of the circuit, so that it triggers at a particular temperature.

We can also change the circuit to include other components or sensors to detect other environmental factors, such as light or humidity.

We supply power to the circuit, the thermistor senses the temperature and its resistance changes accordingly.

The potentiometer allows the user to set a specific temperature threshold. If the temperature exceeds this threshold, the voltage at the base of the transistor increases, allowing the current to flow through it and activating the LED and buzzer.

The 1k base resistor is used to limit the current flowing into the base of the transistor. The LED serves as an indicator of the circuit’s operation, while the buzzer produces an audible alarm to alert the user of the temperature increase.

The 9-volt battery is used to provide power to the circuit.

8.5.1 Schematic Diagram of Temperature Sensor Project

8.5.2 Parts List

1x Breadboard 830 points

1x Set of breadboard jumper wires or hook-up wires

1x Set of wire with double end Alligator (Crocodile) clips

1x Wire Cutter/stripper

1x Battery 9-volt

1x Snaps for 9-volt battery

1x Resistor 330Ω (orange orange brown gold) ±5% tolerance, 1/4 Watt

1x Resistor 1kΩ (brown black red gold) ±5% tolerance, 1/4 Watt

1x Potentiometer (POT) 1kΩ (1 kilo ohms)

1x Knob for potentiometer

1x Light-Emitting Diode (LED) Red color

1x NTC Thermistor 10 kilo ohms

1x Buzzer (5 volts)

1x Transistor BC547

1x Water glass or tumbler or any non-metallic container.

8.5.3 Pin Configurations

8.5.4 Breadboard Wiring Diagram of Temperature Sensor Project

8.6 Build a Sound Sensor Project

A sound sensor circuit is an electronic project that uses a microphone or other sound sensor to detect changes in sound levels.

The circuit can trigger an alarm or activate a device when it detects a certain sound level.

Security systems and noise monitoring applications frequently use sound sensor circuits.

We are using “Electret Microphone” in the sound sensor project.

Electret Microphone

An electret microphone is a type of device that is used to capture sound.

When we speak or make noise, the sound waves travel through the air and reach the Electret microphone.

It is like the microphone you might use to record your voice, but it works slightly differently.

Instead of using a traditional moving coil like a dynamic microphone, an electret microphone uses a special material called an “electret”.

This material is a type of plastic treated with a special charge, which means it has a permanent electrical field and it doesn’t need an external power source like a battery to work.

When sound waves hit the electret microphone, the electret material vibrates, which causes changes in the electrical field.

We then converted these changes into an electrical signal that other devices can record and process, like computers or speakers.

We commonly use electret microphones in many applications, such as musical instruments, cell phones, laptops, and digital recorders. They’re popular because they’re small, efficient, and can capture sound with high fidelity.

8.6.1 Schematic Diagram of Sound Sensor Project

8.6.2 Parts List

1x Breadboard 830 points

1x Set of breadboard jumper wires or hook-up wires

1x Wire Cutter/stripper

2x Cell AA type

1x Battery holder 3 volts (for two AA cells)

2x Resistor 10kΩ (brown black orange gold) ±5% tolerance, 1/4 Watt

1x Resistor 1MegaΩ (brown black green gold) ±5% tolerance, 1/4 Watt

1x Electrolytic capacitor 1µF

1x Light Dependent Resistor (LDR)

2x Transistor BC547

1x Electret microphone with pins

8.6.3 Pin Configurations

8.6.4 Breadboard Wiring Diagram of Sound Sensor Project

DC Motor Project

A DC motor is a type of electronic device that can turn electrical energy into mechanical energy.

It works by using a magnetic field to make a metal coil (also called an armature) spin around an axis.

The coil produces a magnetic field that interacts with the magnetic field of a fixed magnet inside the motor when an electrical current passes through it.

This interaction results in the coil's rotation, which can power various things such as toys, robots, and even cars.

DC motors are called "DC" because they run on direct current, so the electrical current flows in one direction only.

This differs from alternating current (AC), which changes direction back and forth.

DC motors are an important part of many electronic devices, and they're a lot of fun to experiment with and learn about!

8.7 Build a DC Motor Speed Control Project

A DC motor control circuit is an electronic project that involves using a motor controller to regulate the speed of a DC motor.

The circuit can control speed a toy DC motor.

We commonly use DC motor control circuits in robotics and automation applications.

8.7.1 Schematic Diagram of DC Motor Speed Control Project

8.7.2 Parts List

1x Breadboard 830 points

1x Set of breadboard jumper wires or hook-up wires

1x Set of wire with double end Alligator (Crocodile) clips

1x Wire Cutter/stripper

1x Battery 9-volt

1x Snaps for 9-volt battery

1x Resistor 10kΩ (brown black orange gold) ±5% tolerance, 1/4 Watt

1x Transistor BC548

1x Potentiometer (POT) 1kΩ (1 kilo ohms)

1x Knob for potentiometer

1x Toy DC motor 9-volt

1x Mini plastic fan for toy DC motor

8.7.3 Pin Configurations

8.7.4 Breadboard Wiring Diagram of DC Motor Speed Control Project

Alarm Project

An alarm is an electronic device that produces a loud sound or noise to alert people about a specific event or situation.

We often use it as a safety measure to warn people of danger, such as a fire, an intruder, or a gas leak.

The alarm typically comprises a sensor or detector that detects the event or situation and triggers the sound-producing mechanism.

For example, a smoke detector may sense smoke and trigger a loud alarm to warn people of a potential fire.

There are many alarms, including simple ones like a doorbell or more complex ones like a security system.

We can also customize some alarms with unique sounds or tones to differentiate between discrete events.

Electronics incorporate alarms in many settings, including homes, businesses, and public places, making them a vital component.

They help keep people safe by alerting them to potential dangers and allowing them to take action to avoid harm.

8.8 Musical Alarm Circuit Using IC UM66/BT66 Project

IC UM66 and BT66 is a type of integrated circuit that is commonly used in electronic devices such as musical alarm, toys, doorbells, and musical greeting cards.

It is a small chip that contains a pre-programmed melody or tone generator.

When a voltage applies to the IC, it generates an output signal that produces a particular melody or tone.

The melody or tone is determined by the specific programming of the IC.

IC UM66 and BT66 we often use in simple electronic projects for kids because it is easy to use and requires only a few additional components to create a functioning circuit.

Kids can use it to add sound effects to their projects or even build their own musical instruments.

There may be variations in the songs/melodies produced by different manufacturers or versions of these components.

The specific part number for each song/melody may vary depending on the manufacturer and version of the IC UM66 and IC BT66 being used.

For example, UTC Company (UNISONIC TECHNOLOGIES CO., LTD) manufacturing UM66TXXL series IC.

XX stands for two-digit number represent name of song/melody.

The table below shows the IC part number and name of song/melody manufacture by UTC Company as given in their datasheet.

Therefore, it's best to refer to the datasheet provided by the manufacturer to determine the exact part numbers and specifications of these components.

8.8.1 Schematic Diagram of Musical Alarm Using IC UM66/BT66 Project

8.8.2 Parts List

1x Breadboard 830 points

1x Set of breadboard jumper wires or hook-up wires

1x Wire Cutter/stripper

2x Cell AA type

1x Battery holder 3 volts (for two AA cells)

1x Resistor 4.7kΩ (yellow violet red gold) ±5% tolerance, 1/4 Watt

1x Electrolytic capacitor 1µF

1x Transistor BC548

1x IC UM66 or BT66

1x Mini speaker 8 ohms

8.8.3 Pin Configurations

8.8.4 Breadboard Wiring Diagram of Musical Alarm Using IC UM66/BT66 Project

Ohm's Law Experiment

8.9 Verification of Ohm's Law

In a previous chapter, you learned that Ohm’s law is a fundamental principle in electricity that aids our comprehension of how electric circuits function.

Ohm’s law states that “when voltage applies across a material, the amount of electric current flowing through it is directly proportional to the voltage and inversely proportional to its resistance.”

In simpler terms, if you increase the applied voltage in a circuit while maintaining the same resistance, the current flowing through it will also increase.

To confirm Ohm’s law principle in an experiment, you can construct a basic circuit with a battery, a resistor, a voltmeter, and an ammeter to measure the voltage and current.

Afterward, you can alter the voltage across the resistor and measure the resulting current that passes through it.

By recording the observed measurements in an observation table, you can confirm that the current is directly proportional to the voltage and inversely proportional to the resistance.

Plotting this data on a graph supports the notion that the current is directly proportional to the voltage and inversely proportional to the resistance.

Experiment helps to understand how to regulate the flow of electricity through a circuit by adjusting the voltage and resistance.

It enables calculation of power and energy consumption in a circuit, which is critical for electrical systems’ design and maintenance.

DC Voltmeter

A Direct Current (DC) voltmeter is a special tool that we used to measure the strength of electricity flowing through a battery or other DC electrical device.

It works by connecting across (connecting parallel) the device we want to measure, and then the voltmeter shows us the measurement on a screen or display.

The DC voltmeter symbol represents a device used to measure the amount of DC voltage in a circuit.

It is a simple device that has two connectors/probes, one positive and one negative, which we can connect to different parts of a circuit to measure the voltage.

The symbol for a DC voltmeter has a letter "V" which represent volt with a straight line drawn underneath it.

DC Ammeter

A Direct Current (DC) ammeter is a tool used to measure the amount of direct current flowing through a wire or circuit.

It works by connecting the ammeter in series with the wire or circuit being measured, so the electric current flows through the ammeter and the ammeter measures it.

The symbol for a DC ammeter has a letter A, which represents an ampere with a straight line drawn underneath it.

DC ammeter also measure in ampere sub units such as micro-ampere and milli-ampere.

If you imagine a circuit with a battery and a light bulb, for example, you could connect a DC ammeter in between the battery and the light bulb to measure how much current is flowing through the circuit.

The ammeter would show you the amount of current in units called amperes, or amps for short.

Multimeter as a Voltmeter and an Ammeter

As mentioned in the previous chapter, a multimeter is a tool used to measure different units like voltage, current, and resistance. It has a display that shows the measurement in numbers.

NOTE: If you have a DC voltmeter 20V range and DC ammeter 200mA range, then you can use them in this experiment instead of the digital multimeter.

Multimeter as a Voltmeter

To use a multimeter as a DC voltmeter, you need to set it to measure DC voltage. A knob or button on the multimeter that lets you choose the measurement type you want to take.

DC voltage, which is represented by the symbol V. Once you’ve selected the DC voltage setting, you can connect the multimeter to the circuit you want to measure.

Refer to the photo below to set the multimeter as a DC voltmeter in 20V (20 Volts) range.

To do this, you’ll need to use the multimeter’s probes. The red probe is for positive connection, and the black probe is for negative connection.

The pictorial diagram of Ohm’s law experiment in the forthcoming section shows how to connect the multimeter to measure DC voltage across a resistor. The multimeter will display the voltage measurement.

Multimeter as an Ammeter

To use a multimeter as an ammeter, you need to set it to measure DC current. Again, a knob or button on the multimeter that lets you choose the measurement type you want to take.

For DC current, you’ll want to select the DC current setting, which is usually represented by the symbol A.

Refer to the photo below to set the multimeter as a DC milli-ammeter in 200mA (200 milli-amperes) range.

Once you’ve selected the DC current setting, you’ll need to connect the multimeter to the circuit you want to measure.

However, this time you’ll need to connect the multimeter in series with the circuit. That means you’ll need to break the circuit and connect the multimeter between the two ends.

Make sure you connect the red probe to the positive end and the black probe to the negative end. The multimeter will display the current measurement.

The pictorial diagram of Ohm’s law experiment in the forthcoming section shows how to connect the multimeter to measure DC milli-amperes through a resistor. The multimeter will display the current measurement.

It’s important to be careful when using a multimeter, especially when measuring current.

Make sure you read and follow the instructions that come with your multimeter.

Always make sure you turn the power supply OFF to the circuit before you connect the multimeter, and never touch the probes to both ends of a circuit at the same time.

8.9.1 Schematic Diagram of Ohm's Law Experiment

8.9.2 Pictorial Diagram of Ohm's Law Experiment

8.9.3 Parts List

1x Breadboard 830 points

1x Set of breadboard jumper wires or hook-up wires

1x Set of wire with double end Alligator (Crocodile) clips

1x Wire Cutter/stripper

1x Battery 9-volt

1x Snaps for 9-volt battery

2x Digital Multimeter (DMM) with set of probes

1x Resistor 100Ω (brown black brown) ±5% tolerance, 1/4 Watt

1x Potentiometer (POT) 1kΩ ohms (1 kilo ohms)

1x Knob for potentiometer

1x SPST Switch toggle type

8.9.4 Pin Configurations

8.9.5 Procedure

-You have the option to use a breadboard or you can use crocodile clip wires (alligator clip wires) for components and digital multimeter (DMM) connections.

-As shown in the schematic diagram, connect all components and digital multimeters DMM 1 and DMM 2, except the 9 Volts battery.

-Refer to pictorial diagram for connections.

-Make sure the SPST switch (SW1) is OFF.

-You should check for loose connections, and check for polarities such as red and black probes of multimeter and “+” and “–” (positive and negative) terminals of 9 Volts battery.

-Once you make sure every connection is alright, set the voltage range on DMM 1 to 20V which you are using as a voltmeter.

-Set the current range to 200mA on DMM 2, which you are using as an ammeter.

-If your digital multimeter has an independent ON/OFF switch, then turn ON the switch.

-Connect the 9 Volts battery to the snap and switch ON the SPST switch (SW1).

-Turn the 1k potentiometer knob till you read 1 Volts (1V) on the digital multimeter DMM 1 which you connected across (parallel) 100 Ohm resistor.

-Observe the current readings on the digital multimeter DMM 2, which you connected in series with 100 Ohm resistor. Record the readings in the observation table under “DC Current Measured in mA” for the first row correspond to 1V.

-Now repeat the above step from 2V Volts (2V) to 6 Volts (6V) and record the corresponding current readings.

-Apply Ohm’s law formula R = V/I for each row of trial number, calculate resistance and record the result under corresponding “Resistance Calculated” column.

-Add all six calculated resistance and find the total resistance (Total RΩ).

-To calculate “Mean Resistance” use the formula:

-Mean Resistance = Total RΩ / 6

Result:

You are using 100Ω ± 5% resistor.

Your calculated mean resistance should be anywhere between 95Ω to 105Ω.

Option

The good practice is to use two independent meters for Ohm’s law experiment.

Anyway, you have an option to use a single digital multimeter as a voltmeter and as an ammeter.

If you have only one digital multimeter (DMM), you can use it as a DC voltmeter and as a DC ammeter.

Note: This method is time consuming. Every time you should change wiring of the circuit on the breadboard and check for proper connections to avoid measurement errors.

For trail 1, refer to the above schematic diagram below and set the voltage range to 20V on the digital multimeter and connect it across (parallel) 100 Ohm resistor. Observe voltage reading and record in the observation table in the corresponding column.

Now, refer to the schematic diagram below and set the current range on the digital multimeter to 200mA and connect it in series with 100 Ohm resistor.

Observe current reading and record in the observation table in the corresponding column.

Repeat the steps you did for trial 1 for the remaining trials 2 to 6 and proceed to the calculation part.

8.9.6 Observation Table

Chapter 9

Troubleshooting and Maintenance

Sometimes, electronic circuits and devices might not work properly, here troubleshooting comes in.

Troubleshooting is figuring out what's wrong with an electronic circuit and device when it's not working as expected.

It involves identifying the problem, understanding how the circuit and device works, and then trying to fix the issue.

For example, if your computer screen goes black and stops working, troubleshooting might involve checking the power supply, making sure all the cables connect properly, and then restarting the computer.

Maintenance is another important part of working with electronics. It involves taking care of electronic devices to prevent problems from happening.

For example, if you want to make sure your computer stays in good working order, you might clean the dust out of it every few months, update the software regularly, and avoid spilling drinks on the keyboard.

9.1 Basic Troubleshooting Techniques

The key is being methodical and patient.

When you're working on electronics projects, it's common to encounter circuits that don't work as expected.

This can frustrate, but it's important to remember that troubleshooting is a normal part of the process.

Here are some basic techniques you can use to identify and fix problems with your circuits.

Check your connections

Make sure the connections are secure.

Sometimes a wire can come loose or a component connected to the wrong part of the circuit, causing it to malfunction.

Test your power source.

If your circuit isn't working, it's possible that your power source is the problem. Use a multimeter to test the voltage and current coming from your power supply.

Make sure it's delivering the right amount of power to your circuit.

Check your components

If your connections and power source are fine, the next step is to check your components.

Examine for signs of damage or wear, such as burned-out resistors or bulging or leaking capacitors, and substitute any impaired components as required.

Trace the circuit

If you're still having trouble, it's helpful to trace the path of your circuit with a multimeter or oscilloscope.

This can help you identify where the problem is occurring and which components might cause it.

Seek help

If you've tried these troubleshooting techniques and still can't get your circuit to work, don't be afraid to ask for help.

Talk to a teacher, mentor, or other knowledgeable person who can offer guidance and advice.

Keep in mind that troubleshooting circuits require patience and a methodical approach.

Continue until you find a solution. Take the time to solve the problem step-by-step.

With a little practice, you'll be able to fix even the most complex circuits and create amazing electronics projects!

9.2 Safety Precautions

Safety is of paramount importance in any workplace or environment where people are working with potentially dangerous equipment or materials.

To minimize the risk of accidents or injuries, individuals should take several safety precautions.

Ensuring safety depends on providing training for individuals who will work with equipment. This step is essential and makes up a fundamental aspect of safety protocols.

This should include both general safety procedures and specific instructions on how to use the equipment or handle the materials safely.

Ensuring regular maintenance and inspection of all equipment is crucial to identify and rectify any potential safety hazards.

This might involve checking for loose parts, frayed cables, or other signs of wear and tear that could pose a risk.

Another important safety precaution is to ensure that all workers are wearing appropriate protective equipment, such as gloves, goggles, helmets, or earplugs.

This will help to minimize the risk of injury or illness from exposure to hazardous materials or loud noises.

Finally, it is important to have emergency procedures in place in case of accidents or other unexpected events.

This might involve having first aid supplies on hand, posting emergency phone numbers in visible locations, or having an evacuation plan in place.

By taking these safety precautions, employers can help to create a secure workplace for their employees.

Not only does it protect the health and wellbeing of workers, but it also helps to minimize the risk of costly accidents or lawsuits.

9.3 Maintenance Tips

Proper maintenance is essential for ensuring that equipment and systems continue to function effectively.

There are several maintenance tips that can help to extend the lifespan of equipment and minimize the risk of breakdowns or malfunctions.

The first step in maintenance is to ensure that equipment we use correctly and under the manufacturer's instructions.

This might involve following recommended operating procedures, avoiding overloading or overheating the equipment, and using appropriate cleaning and maintenance techniques.

Regular inspection and cleaning are also essential for ensuring that equipment continues to function effectively.

This might involve checking for signs of wear and tear, such as frayed cables, loose parts or other signs of damage.

It is also important to clean equipment regularly to remove dirt, debris, and other contaminants that can interfere with its operation.

Multiple Choice Questions and Answers

Chapter 9

Troubleshooting and Maintenance

Question 1: What is troubleshooting?

A. Figuring out what’s wrong with an electronic circuit and device when it’s not working as expected.

B. Cleaning the dust out of electronic devices.

C. Updating software regularly.

Answer: A. Figuring out what’s wrong with an electronic circuit and device when it’s not working as expected.

Question 2: What does maintenance involve?

A. Taking care of electronic devices to prevent problems from happening.

B. Figuring out what’s wrong with an electronic circuit and device.

C. Checking the power supply and cables of an electronic device.

Answer: A. Taking care of electronic devices to prevent problems from happening.

Question 3: What might troubleshooting involve if your electronic gadget stops working?

A. Call service guy for servicing.

B. Cleaning the dust out of the gadget.

C. Checking the battery/power supply, making sure all the cables connect properly, and then restarting the gadget.

Answer: C. Checking the battery/power supply, making sure all the cables connect properly, and then restarting the gadget.

Question 4: How often should you clean the dust out of your electronic gadget to keep it in good working order?

A. Every day.

B. Every few months.

C. Once a year.

Answer: B. Every few months.

Question 5: What should you avoid doing to your electronic gadget in good working order?

A. Spilling drinks on it.

B. Cleaning it with a damp cloth.

C. Frequently using the gadget.

Answer: A. Spilling drinks on it.

9.1 Basic Troubleshooting Techniques

Question 1: What should you do if you encounter circuits that don’t work as expected?

A. Give up and start a new project.

B. Remember that troubleshooting is a normal part of the process.

C. Ignore the problem and move on to a different project.

D. Hope that the problem will magically fix itself.

Answer: B. Remember that troubleshooting is a normal part of the process.

Question 2: What should you do if a wire comes loose or a component is connected to the wrong part of the circuit?

A. Ignore the problem and hope it fixes itself.

B. Take apart the entire circuit and start over.

C. Make sure the connections are secure.

D. Replace all the components in the circuit.

Answer: C. Make sure the connections are secure.

Question 3: What should you do if your circuit is dead and isn’t working?

A. Give up and start a new project.

B. Assume the problem is with your power source.

C. Test your power source to make sure it’s delivering the right amount of power to your circuit.

D. Assume the problem is with your components.

Answer: C. Test your power source to make sure it’s delivering the right amount of power to your circuit.

Question 4: What should you do if your components show signs of damage or wear?

A. Ignore the problem and hope it goes away.

B. Substitute any impaired components as required.

C. Take apart the entire circuit and start over.

D. Assume the problem is with your power source.

Answer: B. Substitute any impaired components as required.

Question 5: What should you do if you’re still having trouble after checking your connections, power source, and components?

A. Give up and start a new project.

B. Assume the problem is unsolvable and move on to a different project.

C. Trace the path of your circuit with a multimeter or oscilloscope to identify where the problem is occurring.

D. Assume the problem is with the person who designed the circuit.

Answer: C. Trace the path of your circuit with a multimeter or oscilloscope to identify where the problem is occurring.

Question 6: What should you do if you’ve tried all the troubleshooting techniques and still can’t get your circuit to work?

A. Give up and start a new project.

B. Assume the problem is unsolvable and move on to a different project.

C. Ask for help from a teacher, mentor, or other knowledgeable person who can offer guidance and advice.

D. Assume the problem is with your own abilities and stop trying.

Answer: C. Ask for help from a teacher, mentor, or other knowledgeable person who can offer guidance and advice.

9.2 Safety Precautions

Question 1: What is the most important thing in any workplace?

A. Making money.

B. Having fun.

C. Safety

Answer: C. Safety

Question 2: Why is training important in ensuring safety?

A. So workers can take breaks.

B. So workers can learn how to use equipment safely.

C. So workers can socialize.

Answer: B. So workers can learn how to use equipment safely.

Question 3: What should be included in safety training?

A. Only general safety procedures.

B. Only specific instructions on how to use the equipment.

C. Both general safety procedures and specific instructions on how to use the equipment.

Answer: C. Both general safety procedures and specific instructions on how to use the equipment.

Question 4: Why is regular maintenance and inspection of equipment important?

A. To identify and rectify any potential safety hazards.

B. To make the equipment look nice.

C. To save money.

Answer: A. To identify and rectify any potential safety hazards.

Question 5: What is another important safety precaution besides training and maintenance?

A. Wearing appropriate protective equipment.

B. Wearing fancy clothes.

C. Taking long breaks.

Answer: A. Wearing appropriate protective equipment.

Question 6: Why is it important to have emergency procedures in place?

A. To create more work for employees.

B. To have something to do when bored.

C. In case of accidents or other unexpected events.

Answer: C. In case of accidents or other unexpected events.

Question 7: What is the benefit of taking safety precautions for employers?

A. To make workers rejoice.

B. To create a leisure workplace.

C. To protect the health and wellbeing of workers and minimize the risk of accidents or lawsuits.

Answer: C. To protect the health and wellbeing of workers and minimize the risk of accidents or lawsuits.

9.3 Maintenance Tips

Question 1: What is the purpose of proper maintenance for equipment and systems?

A. To ensure they look good.

B. To make them more expensive.

C. To help them last longer and work better.

Answer: C. To help them last longer and work better.

Question 2: What is the first step in maintenance?

A. Regular inspection and cleaning.

B. Using appropriate cleaning and maintenance techniques.

C. Ensuring equipment is used correctly and under the manufacturer’s instructions.

Answer: C. Ensuring equipment is used correctly and under the manufacturer’s instructions.

Question 3: What might be involved in ensuring equipment is used correctly?

A. Following recommended operating procedures.

B. Overloading and overheating the equipment.

C. Using inappropriate cleaning and maintenance techniques.

Answer: A. Following recommended operating procedures.

Question 4: Why is regular inspection and cleaning important for equipment?

A. To make equipment look good and shiny.

B. To remove dirt and debris.

C. To avoid frequent use of equipment.

Answer: B. To remove dirt and debris.

Question 5: What should be checked during regular inspections of equipment?

A. Signs of wear and tear, such as frayed cables and loose parts.

B. Signs of newness, such as shiny parts and clean cables.

C. The color of the equipment.

Answer: A. Signs of wear and tear, such as frayed cables and loose parts.

Chapter 10

Advanced Electronics

10.1 Microcontroller is a tiny computer

Many electronic devices that we use every day, such as smartphones, cars, televisions, household appliances, and even satellites, use microcontrollers.

These tiny computers are a crucial component of electronics and can offer an enjoyable programming experience.

Microcontrollers function as the brain of an electronic device and comprise several parts, including a central processing unit (CPU), memory, and input/output (I/O) ports.

The CPU, akin to a computer's brain, performs all the calculations and decision-making based on instructions.

Meanwhile, memory serves as the microcontroller's storage space, where it can save data and programs. I/O ports enable the microcontroller to interact with the outside world, such as turning on a motor or receiving information from a sensor.

The cool thing is you can program and tell microcontroller what to do with a code.

There are lots of programming languages you can use to program microcontrollers, including Arduino, which is a popular open-source electronics platform based on easy-to-use software and hardware for everyone.

We showed some Arduino boards’ images below. Each board has a dedicated on-board microcontroller.

Each board has its own technical specifications, and we use each module for a specific application. You can make a lot of electronic devices with a little practice.

10.2 Robotics

By programming microcontrollers to control the movements of robots, engineers and researchers can create machines that can perform a wide range of tasks, from exploring the depths of the ocean to assembling products on an assembly line.

Robotics is the branch of engineering that deals with the design, construction, and operation of robots.

Robots are machines that can perform tasks autonomously or with minimal human intervention.

We use them in a wide range of industries, including manufacturing, healthcare, and space exploration. The field of robotics is rapidly advancing, with recent developments such as soft robotics and swarm robotics.

10.3 Internet of Things (IoT)

Besides robotics, microcontrollers are also being used in other innovative technologies, such as the Internet of Things (IoT).

The "internet of things" is a group of devices that are connected to the internet.

The network comprises smartphones, smart appliances, and wearable devices, among others.

IoT has transformative potential in several spheres of daily life, ranging from healthcare to transportation.

However, it also raises concerns about privacy and security, as the proliferation of connect devices creates more opportunities for data breaches and cyber attacks.

The IoT refers to the growing network of devices that are connected to the internet, from smart thermostats and security systems to wearable fitness trackers and self-driving cars.

IoT devices rely on microcontrollers, which facilitate communication between each other and with the internet, as well as enable a diverse array of functions.

10.4 Artificial Intelligence (AI)

Artificial Intelligence (AI) is the branch of computer science that deals with the development of algorithms and systems that can perform tasks that would normally require human intelligence.

They can learn from experience, recognize patterns, and decide based on what they have learned.

If have you ever played a computer or phone game that becomes more challenging as you progress?

Because the game employs AI, to learn from your actions and adjust the difficulty level.

AI has already contributed to develop virtual assistants like Siri and Alexa, which respond when you talk to them on your smart speaker, as well as self-driving cars and facial recognition technology.

AI is increasingly pervasive in our daily lives, and it holds the potential to simplify our lives and aid us in problem-solving.

It's vital to use AI ethically and responsibly to ensure that it benefits people and does not harm them, including avoid potential bias and job loss.

Multiple Choice Questions and Answers

Chapter 10

Advanced Electronics

10.1 Microcontroller is a tiny computer

Question 1: What are microcontrollers?

A. Tiny computers that serve as the brain of an electronic device.

B. Large computers used in satellites.

C. Household appliances used in everyday life.

Answer: A. Tiny computers that serve as the brain of an electronic device.

Question 2: What parts do microcontrollers comprise?

A. CPU, memory, and input/output (I/O) ports.

B. Screen, keyboard, and mouse.

C. Printer, scanner, and photocopier.

Answer: A. CPU, memory, and input/output (I/O) ports.

Question 3: What is the function of the CPU in a microcontroller?

A. It performs all the calculations and decision-making based on instructions.

B. It stores data and programs.

C. It enables the microcontroller to interact with the outside world.

Answer: A. It performs all the calculations and decision-making based on instructions.

Question 4: What is the function of memory in a microcontroller?

A. It performs all the calculations and decision-making based on instructions.

B. It stores data and programs.

C. It enables the microcontroller to interact with the outside world.

Answer: B. It stores data and programs.

Question 5: What is the function of input/output (I/O) ports in a microcontroller?

A. It performs all the calculations and decision-making based on instructions.

B. It stores data and programs.

C. It enables the microcontroller to interact with the outside world.

Answer: C. It enables the microcontroller to interact with the outside world.

Question 6: What is the benefit of programming microcontrollers?

A. You can control electronic devices with a code.

B. You can learn code to complete your school homework.

C. You can practice typing.

Answer: A. You can control electronic devices with a code.

Question 7: What is Arduino?

A. Arduino is an open-source electronics platform based on easy-to-use software and hardware for everyone.

B. A popular video game.

C. A type of electronic gadget.

Answer: A. Arduino is an open-source electronics platform based on easy-to-use software and hardware for everyone.

Question 8: What can you do with a little practice in programming microcontrollers?

A. You can develop lot of electronic devices.

B. You can become a famous repairman.

C. You can become a famous hacker.

Answer: A. You can develop lot of electronic devices.

10.2 Robotics

Question 1: What is robotics?

A. The study of robot actors used in Hollywood movies.

B. The study of machines and their design, construction and automatic operation.

C. The study of geography of the place of ‘robotics’ word origin.

Answer: B. The study of machines and their design, construction and automatic operation.

Question 2: What are robots?

A. Machines that can only perform tasks with human intervention.

B. Machines that can perform tasks autonomously or with minimal human intervention.

C. Machines that can only perform tasks in the outer space.

Answer: B. Machines that can perform tasks autonomously or with minimal human intervention.

Question 3: What is the purpose of programming microcontrollers in robotics?

A. To make robots look cooler.

B. To control the movements of robots.

C. To make robots fly in the air.

Answer: B. To control the movements of robots.

Question 4: In which industries are robots used?

A. Fashion and beauty.

B. Manufacturing, healthcare and space exploration.

C. Music and art.

Answer: B. Manufacturing, healthcare and space exploration.

Question 5: What are some new developments in the field of robotics?

A. Soft robotics and swarm robotics.

B. Cooking robots and cleaning robots.

C. Sports robots and gaming robots.

Answer: A. Soft robotics and swarm robotics.

10.3 Internet of Things (IoT)

Question 1: What is the "internet of things"?

A. A group of devices that are connected to the internet.

B. A group of devices that are not connected to the internet.

C. A group of devices that can only be used offline.

Answer: A. A group of devices that are connected to the internet.

Question 2: What are some examples of devices in the IoT?

A. Only smart refrigerators and smart TVs.

B. Only smartphones and laptops.

C. Smartphones, smart appliances, and wearable devices.

Answer: C. Smartphones, smart appliances, and wearable devices.

Question 3: What is the potential of IoT in daily life?

A. It has no potential in daily life.

B. It has transformative potential in several spheres of daily life, ranging from healthcare to transportation.

C. It only has potential in the field of entertainment.

Answer: B. It has transformative potential in several spheres of daily life, ranging from healthcare to transportation.

Question 4: What are some concerns about the IoT?

A. Privacy and security.

B. Sustainability and affordability.

C. Compatibility and functionality.

Answer: A. Privacy and security.

Question 5: What enables IoT devices to communicate with each other and with the internet?

A. Microcontrollers

B. Batteries

C. Wi-Fi and similar communications.

Answer: C. Wi-Fi and similar communications.

10.4 Artificial Intelligence (AI)

Question 1: What is Artificial Intelligence (AI)?

A. A type of video game.

B. A branch of computer science that deals with the development of algorithms and systems that can perform tasks that would normally require human intelligence.

C. A type of robot.

Answer: B. A branch of computer science that deals with the development of algorithms and systems that can perform tasks that would normally require human intelligence.

Question 2: What are some examples of AI technology?

A. Virtual assistants like Siri and Alexa.

B. Self-driving cars.

C. Facial recognition technology.

D. All of the above.

Answer: D. All of the above.

Question 3: What are some ethical concerns related to AI technology?

A. Potential bias.

B. Job displacement.

C. Both A and B.

D. Neither A nor B.

Answer: C. Both A and B.

Chapter 11

Standard Value Resistors with Color Code

Selected common use resistor values with color codes for ±5% tolerance resistors are in the list below.

NOTE: Ohm (Ω) replaces with letter E in some circuits/schematics, books and technical documents.

Ohms

1E or 1ohm or 1Ω (brown black gold gold) ±5% tolerance

10E (brown black gold) ±5% tolerance

15E (brown green black gold) ±5% tolerance

56E (green blue black gold) ±5% tolerance

15E (brown green black gold) ±5% tolerance

68E (blue gray black gold) ±5% tolerance

10E (brown black black gold) ±5% tolerance

22E (red red black gold) ±5% tolerance

33E (orange orange black gold) ±5% tolerance

47E (yellow violet black gold) ±5% tolerance

100E (brown black brown) ±5% tolerance

120E (brown red brown) ±5% tolerance

150E (brown green brown) ±5% tolerance

180E (brown gray brown) ±5% tolerance

220E (red red brown gold) ±5% tolerance

270E (red violet brown gold) ±5% tolerance

330E (orange orange brown gold) ±5% tolerance

390E (orange white brown gold) ±5% tolerance

470E (yellow violet brown gold) ±5% tolerance

510E (green brown brown gold) ±5% tolerance

560E (green (blue brown gold) ±5% tolerance

620E (blue red brown gold) ±5% tolerance

680E (blue gray brown gold) ±5% tolerance

820E (gray red brown gold) ±5% tolerance

Kilo (k) is 10 power 3

1kΩ or 1 kilo ohm or 1kilo Ω (brown black red gold) ±5% tolerance

2kΩ (red black red gold) ±5% tolerance

1.2kΩ (brown red red gold) ±5% tolerance

1.5kΩ (brown green red gold) ±5% tolerance

1.8kΩ (brown gray red gold) ±5% tolerance

2kΩ (red black red gold) ±5% tolerance

2.2kΩ (red red red gold) ±5% tolerance

2.7kΩ (red violet red gold) ±5% tolerance

3.3kΩ (orange orange red gold) ±5% tolerance

3.9kΩ (orange white red gold) ±5% tolerance

4.7kΩ (yellow violet red gold) ±5% tolerance

5.6kΩ (green blue red gold) ±5% tolerance

5.8kΩ (green gray red gold) ±5% tolerance

6.8kΩ (blue gray red gold) ±5% tolerance

7.5kΩ (violet green red gold) ±5% tolerance

8.2kΩ (gray red red gold) ±5% tolerance

10kΩ (brown black orange gold) ±5% tolerance

15k Ω (brown green orange gold) ±5% tolerance

18k Ω (brown gray orange gold) ±5% tolerance

20k Ω (red black orange gold) ±5% tolerance

22k Ω (red red orange gold) ±5% tolerance

27k Ω (red violet orang gold) ±5% tolerance

33k Ω (orange orange orange gold) ±5% tolerance

39k Ω (orange orange white gold) ±5% tolerance

47k Ω (yellow violet orange gold) ±5% tolerance

51k Ω (green white orange red gold) ±5% tolerance

68k Ω (blue gray orange gold) ±5% tolerance

82k Ω (gray red orange gold) ±5% tolerance

100k Ω (brown black yellow gold) ±5% tolerance

120k Ω (brown red yellow gold) ±5% tolerance

150k Ω (brown green yellow gold) ±5% tolerance

220k Ω (red red yellow gold) ±5% tolerance

270k Ω (red violet yellow gold) ±5% tolerance

330k Ω (orange orange yellow gold) ±5% tolerance

390kΩ (orange white yellow gold) ±5% tolerance

470kΩ (yellow violet yellow gold) ±5% tolerance

500kΩ (green black yellow gold) ±5% tolerance

560kΩ (green (blue yellow gold) ±5% tolerance

680kΩ (blue gray yellow gold) ±5% tolerance

750kΩ (violet green yellow gold) ±5% tolerance

Mega (M) is 10 power 6

1MΩ or 1 Mega ohm or 1 Mega Ω (brown black green gold) +5% tolerance

1.2MΩ (brown red green gold) +5% tolerance

1.5MΩ (brown green green gold) +5% tolerance

2.2MΩ (red red green gold) +5% tolerance

2.7MΩ (red violet green gold) +5% tolerance

3.3MΩ (orange orange green gold) +5% tolerance

4.7MΩ (yellow violet green gold) +5% tolerance

6.8MΩ (blue gray green gold) +5% tolerance

10MΩ (brown black blue gold) +5% tolerance

Chapter 12

Standard Value Capacitors with Code and Value Conversion

Selected common use capacitor values with codes and converted values are in the list below.

Chapter 13

Analog and Digital Electronics

13.1 Analog Electronics

Analog electronics refers to the type of electronic system that uses continuous signals to represent information.

It is a branch of electronics that deals with signals that continuously vary over time.

These signals can be any physical quantity that varies continuously, such as voltage or current.

For example, analog radio receive analog signals from the radio station. These signals are then converted into sound waves using analog circuits within the radio that we can hear.

Another example of analog electronics is the amplifier. An amplifier is an electronic device that increases the amplitude of an analog signal.

Amplifiers are used in a wide range of applications, from musical instruments to power supplies.

One more example of analog electronics is the thermometer. A thermometer works by measuring the resistance of a metal wire, which varies with temperature.

The resistance value is then converted into an analog voltage signal, which can be read and displayed on a gauge or digital display.

Analog electronics has many other applications as well, including in sensors, medical equipment, and industrial control systems.

13.2 Digital Electronics

Digital electronics is a type of electronic system that uses discrete signals to represent information.

It is a branch of electronics that deals with signals with discrete values or levels, as opposed to analog electronics which deals with continuous signals.

These signals can be either "on" or "off," represented by the binary digits 1 and 0, respectively. For example, a computer uses digital electronics to process and store information.

Digital signals are discrete signals that are represented by binary digits, or bits, that can have only two values: 0 or 1.

These signals are used in a wide range of electronic devices, from simple calculators to complex computers.

One example of digital electronics is the simple calculator. When you enter a number into a calculator, it is converted into a digital signal consisting of a series of 0's and 1's.

The calculator then uses a series of logic gates to perform the necessary mathematical operations, such as addition or subtraction, before displaying the result on the screen.

Another example of digital electronics is the computer. A computer is made up of a complex network of electronic components, including processors, memory, and storage devices, all of which operate on digital signals.

When you type a letter on a keyboard, for example, it is converted into a digital signal that is processed by the computer's central processing unit (CPU) and stored in memory.

Digital electronics is also used in many other devices, such as cell phones, digital cameras, and televisions.

In a cell phone, for instance, digital signals are used to transmit voice and data over a wireless network.

In a digital camera, digital signals are used to capture and process images, which can then be stored on a memory card. In a television, digital signals are used to transmit high-definition video and audio signals.

Both analog and digital electronics have their own advantages and disadvantages. Analog electronics can process a wide range of signals, but it may suffer from noise and interference. Digital electronics can process information quickly and accurately, but it requires more complex circuits.

Multiple Choice Questions and Answers

Chapter 13

Analog and Digital Electronics

13.1 Analog Electronics

Question 1: What is analog electronics?

A. A type of electronic system that uses only discrete signals.

B. A branch of electronics that deals with signals that continuously vary over time.

C. An electronic system can take on finite number of values within a given range.

D. None of the above

Answer: B. A branch of electronics that deals with signals that continuously vary over time.

Question 2: Which physical quantities can be used to represent continuous signals in analog electronics?

A. Only voltage.

B. Only current.

C. Physical quantity that varies continuously.

D. Only digital signals.

Answer: C. Physical quantity that varies continuously.

Question 3: What does an analog radio receive from the radio station?

A. Magnetic waves.

B. Analog signals.

C. Sound waves.

D. None of the above

Answer: B. Analog signals.

Question 4: How does an amplifier work?

A. It converts analog signals into digital signals.

B. It decreases the amplitude of an analog signal.

C. It increases the amplitude of an analog signal.

D. It converts digital signals into analog signals.

Answer: C. It increases the amplitude of an analog signal.

Question 5: What is the function of a thermometer in analog electronics?

A. To measure the inductance of a metal wire.

B. To convert analog signals into digital signals.

C. To measure the resistance of a metal wire, which varies with temperature.

D. To measure the current of a metal wire.

Answer: C. To measure the resistance of a metal wire, which varies with temperature.

13.2 Digital Electronics

Question 1: What is digital electronics?

A. A type of electronic system that uses continuous signals to represent information.

B. A branch of electronics that deals with signals with discrete values or levels.

C. A type of computer that uses continuous signals to process and store information.

D. A type of calculator that uses continuous signals to perform mathematical operations.

Answer: B. A branch of electronics that deals with signals with discrete values or levels.

Question 2: What are digital signals?

A. Signals that are represented by continuous values.

B. Signals that are represented by binary digits with only two values: 0 or 1.

C. Signals that are represented by decimal digits with ten values: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.

D. Signals that are represented by digits with 4 values: 0, 1, 2, and 3.

Answer: B. Signals that are represented by binary digits with only two values: 0 or 1.

Question 3: How does a calculator use digital electronics to perform mathematical operations?

A. By converting numbers into continuous signals.

B. By using a series of logic gates to perform necessary operations.

C. By displaying the result on the screen using analog signals.

D. By storing the result in memory using infinite signals.

Answer: B. By using a series of logic gates to perform necessary operations.

Question 4: What is the role of CPU in a computer?

A. To transmit voice and data over a wireless network on its own.

B. To capture images.

C. To process digital signals.

D. To control electronic components on the circuit board of computer.

Answer: C. To process digital signals.

Chapter 14

Measurement Units

Measurement units in electronics are a way to express the size or amount of things that we are measuring.

These units help us understand the quantities involved in electrical circuits and electronics.

Some of most common use measurement units are given in this chapter.

14.1 Resistance Measurement Units

1 Ohm (1Ω): One ohm is the resistance of a conductor in which a current of one ampere is produced by a potential difference of one volt.

1 Kilohm (1kΩ) = One kilohm is equal to 1,000 ohms.

1 Megohm (1MΩ) = One megohm is equal to 1,000,000 ohms.

1 microohm (1μΩ) = One microohm is equal to one millionth of an ohm.

1 milliohm (1mΩ) = One milliohm is equal to one thousandth of an ohm.

14.2 Capacitance Measurement Units

1 Farad (1F): One farad is defined as the amount of capacitance required to store one coulomb of charge at a potential difference of one volt.

1 Farad (1F) = 1 coulomb (C) / 1 volt (V)

1 microfarad (1μF) = 10^-6 farads (F)

1 nanofarad (1nF) = 10^-9 farads (F)

1 picofarad (1pF) = 10^-12 farads (F)

14.3 Inductance Measurement Units

1 Henry (1H): One henry is defined as the inductance of a circuit in which an electromotive force of one volt is induced when the current in the circuit varies at a rate of one ampere per second.

1 millihenry (1mH) = 1/1000 of a Henry

1 microhenry (1μH) = 1/1,000,000 of a Henry

1 nanohenry (1nH) = 1/1,000,000,000 of a Henry

1 picohenry (1pH) = 1/1,000,000,000,000 of a Henry

14.4 Voltage Measurement Units

1 Volt (1V): It represents the amount of electric potential energy that is required to move one unit of electric charge from one point to another in an electric circuit with a resistance of one ohm, without producing any net flow of charge.

More precisely, one volt is defined as the potential difference between two points in a conductor where the passage of one ampere of current will produce a power dissipation of one watt.

One volt is a unit of measurement for electric potential or electromotive force (EMF).

Mathematically, 1 volt is equal to the ratio of the amount of electric energy transferred to the amount of electric charge moved, or V = W/Q, where V is voltage (in volts), W is electric energy (in joules), and Q is electric charge (in coulombs).

millivolts (mV): One millivolt is equal to one-thousandth of a volt. This unit is commonly used to measure small voltage differences.

Kilovolts (kV): One kilovolt is equal to one thousand volts. This unit is commonly used to measure high voltage differences, such as those found in power lines.

Megavolts (MV): One megavolt is equal to one million volts. This unit is used to measure extremely high voltage differences, such as those found in lightning strikes.

14.5 Electric Current Measurement Units

Ampere (A): Ampere is the SI unit of electric current. One ampere is defined as the amount of electric current that flows through a conductor when a potential difference of one volt is applied across it and the resistance of the conductor is one ohm. Ampere is often abbreviated as "amp".

1 Ampere (1A): One ampere of current is defined as the flow of one coulomb of electric charge per second. A coulomb is the unit of electric charge and is equal to the charge carried by a current of one ampere flowing for one second.

In other words, if a current of 1A is flowing through a wire, it means that one coulomb of electrical charge (which is approximately 6.24 x 10^18 electrons) is passing through that wire each second.

1 milliampere (1mA): milliampere is one-thousandth of an ampere. It is commonly used to measure small currents in electronic circuits.

1 microampere (1μA): microampere is one-millionth of an ampere. It is also commonly used to measure small currents in electronic circuits.

1 nanoampere (1nA): nanoampere is one-billionth of an ampere. It is used to measure extremely small currents, such as those in biological and chemical experiments.

Coulomb per second (C/s): Coulomb per second is another unit of electric current that is used in some contexts.

It is equivalent to the ampere, as one ampere is the flow of one coulomb of charge per second.

14.6 Electric Power Measurement Units

Watt is a unit of power, which measures the rate at which energy is transferred, consumed or produced.

It is named after James Watt, a Scottish inventor and mechanical engineer who developed the steam engine.

Watt developed the concept of Horsepower (hp), the SI unit of power, the watt, was named after him.

Electric power measurement is typically expressed in terms of units of watt (W).

1 Watt (W): One watt (1 W) is defined as the amount of power that is dissipated when one ampere of current flows through a circuit with a potential difference of one volt (1 V).

In other words, it is the rate at which energy is transferred or used when one joule of energy is used in one second.

Kilowatt (kW): This unit is equal to 1,000 watts. It is typically used to measure the power output of small power plants or other low-power applications.

Megawatt (MW): This unit is equal to 1,000 kilowatts or 1 million watts. It is typically used to measure the power output of large power plants or other high-power applications.

Gigawatt (GW): This unit is equal to 1,000 megawatts or 1 billion watts. It is used to describe the power output of extremely large power plants or other high-power applications.

Volt-ampere (VA): This unit is used to measure the apparent power in an electrical circuit, which is the product of the voltage and current in the circuit. It is often used in the context of AC (alternating current) power systems.

Kilovolt-ampere (kVA): This unit is equal to 1,000 volt-amperes and is commonly used to measure the power capacity of transformers and other electrical equipment.

14.7 Frequency Measurement Units

Frequency, which is the number of occurrences of a repeating event per unit of time, is typically measured in Hertz (Hz) or its multiples.

Heinrich Hertz was a German physicist and experimentalist who showed that the electromagnetic waves predicted by James Clerk Maxwell exist.

Hertz is also the man whose peers honored by attaching his name to the unit of frequency; a cycle per second is one Hertz.

1 Hertz (1Hz): One Hertz is equal to one cycle per second. It is a unit of frequency that measures the number of cycles per second of a periodic signal such as an electrical wave or a sound wave.

Comparison of 1Hz and 2Hz Waveforms

For example, if a signal oscillates or repeats its cycle 10 times per second, its frequency would be 10Hz.

Similarly, if a signal oscillates or repeats its cycle 1000 times per second, its frequency would be 1000Hz or 1kilohertz (kHz).

In general, Hertz is used to measure the frequency of various electronic signals such as radio waves, AC power, digital clock signals, and more.

Here are some commonly used frequency measurement units:

Hertz (Hz): One cycle per second.

Kilohertz (kHz): One thousand cycles per second.

Megahertz (MHz): One million cycles per second.

Gigahertz (GHz): One billion cycles per second.

Terahertz (THz): One trillion cycles per second.

For example, the frequency of a standard AC power supply is 50Hz or 60Hz depending on the country.

The frequency of a radio signal can range from a few kHz to several GHz depending on the frequency band.

The frequency of a computer's central processing unit (CPU) can range from a few GHz to over 5GHz.

14.8 Digital Measurement Units

Basic Units of Digital Information Storage are fundamental measurements used to quantify the amount of digital data.

These units are hierarchical and represent different orders of magnitude in data storage. The primary units are:

Bit (Binary Digit):

- The smallest and most fundamental unit of digital information.

- Represents a binary choice between two values: 0 or 1.

- Often used in the context of data transmission, binary code, and Boolean logic.

Byte:

- Comprises 8 bits, forming a group of information that can represent 256 (2^8) different values.

- A commonly used unit for representing and storing characters and data in computer systems.

- Bytes are the building blocks for most data storage and manipulation.

Kilobyte (KB):

- Approximately 1,024 bytes or 8,192 bits.

- Often used to measure the size of small files, text documents, and simple images.

Megabyte (MB):

- Roughly 1,024 kilobytes or 1,048,576 bytes.

- Used to describe larger files, images, and documents.

Gigabyte (GB):

- About 1,024 megabytes or 1,073,741,824 bytes.

- Commonly used to represent the storage capacity of hard drives, RAM, and the size of multimedia files.

These units provide a standardized way to express the size and capacity of digital data. As you move up the hierarchy, each unit represents an exponential increase in storage capacity.

Understanding these basic units is essential when dealing with digital storage, data transfer, and memory in computing and information technology.

Digital Measurement Unit Equivalents:

Digital Measurement Unit Equivalents are conversions between different units used to measure digital data, storage, and related aspects.

These equivalents help in understanding and comparing the sizes, speeds, and quantities of digital information.

Here are some common basic digital measurement unit equivalents:

Bit (b) and Byte (B): 1 byte consists of 8 bits. Therefore, 1 byte is equivalent to 8 bits.

Kilobyte (KB) and Byte (B): 1 kilobyte is equivalent to 1,024 bytes.

Megabyte (MB) and Kilobyte (KB): 1 megabyte is equivalent to 1,024 kilobytes, or 1,048,576 bytes.

Gigabyte (GB) and Megabyte (MB): 1 gigabyte is equivalent to 1,024 megabytes, or 1,073,741,824 bytes.

Terabyte (TB) and Gigabyte (GB): 1 terabyte is equivalent to 1,024 gigabytes, or 1,099,511,627,776 bytes.

Gigabit (Gb) and Megabit (Mb): 1 gigabit is equivalent to 1,000 megabits.

Megahertz (MHz) and Hertz (Hz): 1 megahertz is equivalent to 1,000,000 hertz.

The unit bps is used to measure the speed of data transmission in bits per second.

Kilobit per second (Kbps) and Bit per second (bps): 1 kilobit per second is equivalent to 1,000 bits per second.

Gigabit per second (Gbps) and Megabit per second (Mbps): 1 gigabit per second is equivalent to 1,000 megabits per second.

Nibble and Byte: 1 nibble is equivalent to half of a byte, which means it consists of 4 bits.

These equivalences are important in various fields, such as data storage, data transfer rates, and computer hardware specifications.

They provide a common language for expressing and comparing quantities of digital information, ensuring consistency and clarity when discussing the capacity or speed of digital systems.

Clock Speed of a Microprocessor:

The clock speed of a microprocessor, often referred to simply as "clock speed," is a crucial specification that measures how fast a central processing unit (CPU) can execute instructions and perform operations.

Here's a detailed explanation of clock speed:

Definition: Clock speed is measured in Hertz (Hz) and represents the number of clock cycles a CPU can complete in one second

Each clock cycle corresponds to a single instruction or operation that the CPU can carry out.

Frequency: The clock speed is often expressed in megahertz (MHz) or gigahertz (GHz), with higher values indicating faster processors.

For example, a CPU with a clock speed of 3.0 GHz can complete 3 billion clock cycles in one second.

Role in Performance: The clock speed is a critical factor in a microprocessor's overall performance.

A higher clock speed means that the CPU can execute instructions more quickly, resulting in faster data processing and more responsive performance.

Parallel Processing: Some modern processors employ multiple cores, allowing them to handle multiple tasks simultaneously.

Each core operates at the same clock speed, so multi-core processors can perform several tasks in parallel, improving overall performance.

Limitations: While clock speed is an important metric, it's not the sole determinant of a CPU's performance.

Other factors, such as architecture, cache size, and the efficiency of instruction execution, also influence how well a processor performs.

Trade-Offs: Manufacturers sometimes face a trade-off between increasing clock speed and managing power consumption and heat generation.

As clock speed increases, power usage and heat production tend to rise as well, which can be a limiting factor in designing portable devices and data centers.

Real-World Impact: Higher clock speeds often lead to better performance in tasks that benefit from single-threaded processing, such as some video games and specific software applications.

Not all tasks can take full advantage of higher clock speeds, so multi-core processors are designed to handle more complex and parallel tasks efficiently.

The clock speed of a microprocessor is a critical specification that measures how quickly a CPU can execute instructions.

It is a fundamental factor in a processor's performance, although it should be considered alongside other factors to assess a CPU's overall capabilities.

RAM (Random Access Memory)

Random Access Memory (RAM) is a fundamental component of a computer's memory hierarchy and is crucial for the functioning of digital devices. Here's an explanation of RAM:

Definition: RAM is a type of computer memory that provides high-speed data storage and quick access to data that the computer's processor (CPU) is actively using or processing.

Unlike long-term storage devices (e.g., hard drives or solid-state drives), RAM is volatile, which means its data is erased when the computer is powered off or restarted.

Role in a Computer: RAM serves as a temporary working space for the computer, allowing the CPU to store and quickly access data it needs to perform tasks. This data includes:

- The operating system.

- Application software.

- Active processes and their data.

- Data required for computations, like variables and buffers.

Faster Access than Storage Drives: RAM is significantly faster than long-term storage devices. It provides almost immediate access to data, which is vital for running applications, multitasking, and overall system responsiveness.

Size and Capacity: RAM modules come in various sizes, such as 4GB, 8GB, 16GB, and beyond.

The amount of RAM a computer has affects its ability to handle complex tasks and multitasking. More RAM allows a computer to run multiple applications smoothly.

Reading and Writing Data: RAM is used to store data that the CPU needs to access quickly.

When the CPU reads or writes data, it does so from or to RAM, which is much faster than reading from or writing to storage drives.

Virtual Memory: When a computer's RAM is fully utilized, it may use a portion of the hard drive or SSD as virtual memory to supplement the available RAM.

This allows the computer to continue running applications, albeit at a slower speed.

Upgradeability: In many cases, RAM can be upgraded in a computer, providing a cost-effective way to improve system performance without replacing the entire computer.

Types of RAM: There are different types of RAM, including DRAM (Dynamic RAM)

SRAM (Static RAM), each with its own advantages and use cases.

DDR (Double Data Rate) Synchronous Dynamic RAM is a common type used in most modern computers.

RAM is a vital component of a computer's memory system, providing quick and temporary storage for data actively being used by the CPU.

Its speed and capacity significantly impact a computer's overall performance and ability to handle tasks efficiently.

Multiple Choice Questions and Answers

Chapter 14

Measurement Units

14.1 Resistance Measurement Units

Question 1: What is an Ohm?

A. A unit of measurement for resistance.

B. A unit of measurement for power.

C. A unit of measurement for current.

Answer: A. A unit of measurement for resistance.

Question 2: How is one Ohm defined?

A. One ohm is the resistance of a conductor in which a current of one ampere is produced by a potential difference of one volt.

B. One ohm is the resistance of a conductor in which a current of 0.5-ampere is produced by a potential difference of two volts.

C. One ohm is the resistance of a conductor in which a current of 1-ampere is produced by a potential difference of 0.5-volt.

Answer: A. One ohm is the resistance of a conductor in which a current of one ampere is produced by a potential difference of one volt.

Question 3: What is a Kilo ohm?

A. One Kilo ohm is equal to 100 ohms.

B. One Kilo ohm is equal to 1,000 ohms.

C. One Kilo ohm is equal to 10,000 ohms.

Answer: B. One Kilo ohm is equal to 1,000 ohms.

Question 4: What is a Mega ohm?

A. One Mega ohm is equal to 100,000 ohms.

B. One Mega ohm is equal to 10,000 ohms.

C. One Mega ohm is equal to 1,000,000 ohms.

Answer: C. One Mega ohm is equal to 1,000,000 ohms.

Question 5:  What is a micro ohm?

A. One micro ohm is equal to one millionth of an ohm.

B. One micro ohm is equal to one thousandth of an ohm.

C. One micro ohm is equal to one billionth of an ohm.

Answer: A. One micro ohm is equal to one millionth of an ohm.

Question 6: What is a milliohm?

A. One milli ohm is equal to one billionth of an ohm.

B. One milli ohm is equal to one millionth of an ohm.

C. One milli ohm is equal to one thousandth of an ohm.

Answer: C. One milli ohm is equal to one thousandth of an ohm.

14.2 Capacitance Measurement Units

Question 1: What is a Farad?

A. A unit of measurement for power.

B. A unit of measurement for capacitance.

C. A unit of measurement for voltage.

Answer: B. A unit of measurement for capacitance.

Question 2: What is the definition of one Farad?

A. The amount of voltage required to store one coulomb of charge.

B. The amount of capacitance required to store one coulomb of charge at a potential difference of one volt.

C. The amount of charge required to store one coulomb of potential difference.

Answer: B. The amount of capacitance required to store one coulomb of charge at a potential difference of one volt.

Question 3: How many microfarads are in one Farad?

A. 10^-3

B. 10^-6

C. 10^-9

Answer: B. 10^-6

Question 4: How many picofarads are in one Farad?

A. 10^-3

B. 10^-6

C. 10^-12

Answer: C. 10^-12

Question 5: What is the equation for one Farad?

A. 1 coulomb / 1 volt

B. 1 volt / 1 coulomb

C. 1 ohm / 1 ampere

Answer: A. 1 coulomb / 1 volt

14.3 Inductance Measurement Units

Question 1: What is a Henry?

A. A unit of measurement for capacitance.

B. A unit of measurement for inductance.

C. A unit of measurement for voltage.

Answer: B. A unit of measurement for inductance.

Question 2: What is a millihenry?

A. 1/10,000 of a Henry.

B. 1/1000 of a Henry.

C. 1/100 of a Henry.

Answer: B. 1/1000 of a Henry.

Question 3: What is a microhenry?

A. 1/1000 of Henry.

B. 1/10000 of a Henry.

C. 1/1000000 of a Henry.

Answer: C. 1/1000000 of a Henry.

Question 4: What is a nanohenry?

A. 1/1000000000 of a Henry.

B. 1/100000000 of a Henry.

C. 1/10000000 of a Henry.

Answer: A. 1/1000000000 of a Henry.

Question 5: What is a picohenry?

A. 1/1000000000000 of a Henry.

B. 1/100000000000 of a Henry.

C. 1/1000000000 of a Henry.

Answer: A. 1/1000000000000 of a Henry.

14.4 Voltage Measurement Units

Question 1: What is a volt?

A. A unit of measurement for current flowing in a conductor.

B. The amount of magnetic energy transferred to the amount of magnetic field moved.

C. A unit of electrical potential difference and electromotive force (EMF).

D. The amount of electromagnetic energy transferred to the amount of electromagnetic field moved.

Answer: C. A unit of electrical potential difference and electromotive force (EMF).

Question 2: What does one volt represent?

A. The amount of electromagnetic field required to move one unit of electric charge from one point to another.

B. The amount of electric potential energy required to move one unit of electric charge from one point to another in an electric circuit with a resistance of one ohm.

C. The amount of electric potential energy required to move one unit of electric charge from one point to another in an electric circuit without any resistance.

D. The amount of magnetic field required to move one unit of electric charge from one point to another.

Answer: B. The amount of electric potential energy required to move one unit of electric charge from one point to another in an electric circuit with a resistance of one ohm.

Question 3: What is the mathematical formula for voltage (V) with respect to work done?

A. V = W/Q

B. V = Q/W

C. V = W x Q

D. V = Q + W

Answer: A. V = W/Q

Question 4: What is one millivolt equal to?

A. One-tenth of a volt.

B. One-hundredth of a volt.

C. One-thousandth of a volt.

D. One-millionth of a volt.

Answer: C. One-thousandth of a volt.

Question 5: What is one kilovolt equal to?

A. One hundred volts.

B. One thousand volts.

C. Ten thousand volts.

D. One million volts.

Answer: B. One thousand volts.

Question 6: What is one megavolt used to measure?

A. Low voltage differences in batteries.

B. High voltage differences, such as those found in power lines.

C. Extremely high voltage differences, such as those found in lightning strikes.

D. None of the above.

Answer: C. Extremely high voltage differences, such as those found in lightning strikes.

14.5 Electric Current Measurement Units

Question 1: What is an ampere?

A. The SI unit of electric current.

B. The unit of electric charge.

C. The unit of electric potential difference.

D. The unit of resistance.

Answer: A. The SI unit of electric current.

Question 2: How is one ampere defined?

A. The flow of ten electrons per second.

B. The flow of one electron per second.

C. The flow of one coulomb of electric charge per second.

D. The amount of electric potential difference applied across a conductor.

Answer: C. The flow of one coulomb of electric charge per second.

Question 3: What is a coulomb?

A. The unit of electric current.

B. The unit of electric charge.

C. The unit of electric potential difference.

D. The unit of inductance.

Answer: A. The unit of electric current.

Question 4: How many electrons are approximately in one coulomb of electric charge?

A. 6.24 x 10^6 electrons.

B. 6.24 x 10^12 electrons.

C. 6.24 x 10^15 electrons.

D. 6.24 x 10^18 electrons.

Answer: D. 6.24 x 10^18 electrons.

Question 5: What is a milliampere?

A. One-thousandth of an ampere.

B. One-millionth of an ampere.

C. One-billionth of an ampere.

D. One-tenth of an ampere.

Answer: A. One-thousandth of an ampere.

Question 6: What is a microampere?

A. One-thousandth of an ampere.

B. One-millionth of an ampere.

C. One-billionth of an ampere.

D. One-tenth of an ampere.

Answer: B. One-millionth of an ampere.

Question 7: What is a nanoampere?

A. One-thousandth of an ampere.

B. One-millionth of an ampere.

C. One-billionth of an ampere.

D. One-tenth of an ampere.

Answer: C. One-billionth of an ampere.

Question 8: What is Coulomb per second?

A. A coulomb / 10 seconds is the unit of electric current and is equivalent to one ampere.

B. A coulomb / 2 seconds is the unit of electric current and is equivalent to one ampere.

C. A coulomb / second is the unit of electric current and is equivalent to one ampere.

D. A coulomb / 100 seconds is the unit of electric current and is equivalent to one ampere.

Answer: C. A coulomb / second is the unit of electric current and is equivalent to one ampere. 

14.6 Electric Power Measurement Units

Question 1: What is a watt?

A. A unit of energy.

B. A unit of power.

C. A unit of current.

D. A unit of voltage.

Answer: B. A unit of power.

Question 2: Who is James Watt?

A. A Scottish inventor and mechanical engineer who developed the steam engine.

B. An American astronaut who landed on the moon.

C. A famous painter from Italy.

D. A famous singer from the UK.

Answer: A. A Scottish inventor and mechanical engineer who developed the steam engine.

Question 3: How is electric power measurement typically expressed?

A. In terms of units of kilogram (kg).

B. In terms of units of meter (m).

C. In terms of units of watt (W).

D. In terms of units of second (s).

Answer: C. In terms of units of watt (W).

Question 4: How is one watt defined?

A. The amount of energy that is transferred when one ampere of current flows through a circuit with a potential difference of one volt (1V).

B. The amount of energy that is consumed when one joule of energy is used in one second.

C. The amount of power that is produced when one ampere of current flows through a circuit with a potential difference of one volt (1V).

D. The amount of power that is dissipated when one ampere of current flows through a circuit with a potential difference of one volt (1V).

Answer: D. The amount of power that is dissipated when one ampere of current flows through a circuit with a potential difference of one volt (1V).

Question 5: What is a kilowatt (kW)?

A. One kilowatt is equal to 100 Watts.

B. One kilowatt is equal to 1000 Watts.

C. One kilowatt is equal to 10000 Watts.

Answer: B. One kilowatt is equal to 1,000 Watts.

Question 6: What is a megawatt (MW)?

A. One megawatt is equal to 1000kW.

B. One megawatt is equal to 1000W.

C. One megawatt is equal to 1000GW.

Answer: A. One megawatt is equal to 1000kW.

Question 7: What is a gigawatt (GW)?

A. One gigawatt is equal to 1000 watt.

B. One gigawatt is equal to 1000 kilowatt.

C. One gigawatt is equal to 1000 megawatt.

Answer: C. One gigawatt is equal to 1000 megawatt.

Question 8: What is a volt-ampere (VA)?

A. A unit of frequency.

B. A unit of power.

C. A unit of current.

D. A unit of voltage.

Answer: B. A unit of power.

Question 9: What is a kilovolt-ampere (kVA) commonly used for?

A. To measure the power output of large power plants.

B. To measure the power capacity of transformers and other electrical equipment.

C. To measure the apparent power in an electrical circuit.

D. To measure the power output of small power plants.

Answer: B. To measure the power capacity of transformers and other electrical equipment.

14.7 Frequency Measurement Units

Question 1: What is frequency?

A. The number of occurrences of a repeating event per unit of time.

B. The unit of measurement for current.

C. The speed at which something moves.

Answer: A. The number of occurrences of a repeating event per unit of time.

Question 2: How is frequency measured?

A. In coulombs (j).

B. In Hertz (Hz) or its multiples.

C. In watts (W).

Answer: B. In Hertz (Hz) or its multiples.

Question 3: What is the frequency of a signal that oscillates 5 times per second?

A. 5Hz

B. 50Hz

C. 500Hz

Answer: A. 5Hz

Question 4: What is the frequency of a signal that oscillates 5000 times per second?

A. 5Hz

B. 50Hz

C. 5kHz

Answer: C. 5kHz

Question 5: What is the unit of frequency that measures one billion cycles per second?

A. Kilohertz (kHz)

B. Megahertz (MHz)

C. Gigahertz (GHz)

Answer: C. Gigahertz (GHz)

Question 6: What is the frequency of a standard AC power supply?

A. 10Hz

B. 50Hz or 60Hz

C. 1000Hz

Answer: B. 50Hz or 60Hz

Question 7: What is the frequency range of a radio signal?

A. From a few Hz to several kHz.

B. From a few kHz to several MHz.

C. From a few MHz to several GHz.

Answer: B. From a few kHz to several MHz.

Question 8: What is the frequency range of a computer's central processing unit (CPU)?

A. From a few Hz to over 5Hz.

B. From a few kHz to over 5kHz.

C. From a few GHz to over 5GHz.

Answer: C. From a few GHz to over 5GHz.

14.8 Digital Measurement Units

Question 1: What is the basic unit of digital information storage?

A. Byte

B. Bit

C. Kilobyte

D. Megabyte

Answer: B. Bit

Question 2: Which digital measurement unit is equivalent to 1,024 bytes?

A. Kilobyte

B. Megabyte

C. Gigabyte

D. Terabyte

Answer: A. Kilobyte

Question 3: Which of the following is a common unit for measuring the clock speed of a microprocessor?

A. Megabyte (MB)

B. Kilohertz (kHz)

C. Terahertz (THz)

D. Kilobyte (KB)

Answer: B. Kilohertz (kHz)

Question 4: How many bits are in a nibble?

A. 4 bits

B. 8 bits

C. 16 bits

D. 32 bits

Answer: A. 4 bits

Question 5: What does the acronym "RAM" stand for in digital electronics?

A. Randomly Accessible Module

B. Read-Only Memory

C. Read and Modify Memory

D. Random Access Memory

Answer: D. Random Access Memory

Question 6: Which unit is used to measure the speed of data transmission in bits per second (bps)?

A. Hertz (Hz)

B. Kilohertz (kHz)

C. Megahertz (MHz)

D. Baud

Answer: D. Baud

Question 7: What is the maximum value that can be represented with 8 bits?

A. 64

B. 256

C. 512

D. 1024

Answer: B. 256

Question 8: In digital electronics, what does the term "Hertz" measure?

A. Memory capacity

B. Clock speed

C. Data storage

D. Signal strength

Answer: B. Clock speed

END