Industrial Electronic Circuits Laboratory Manual 9783031507724, 9783031507731

Table of contents :
Preface
Contents
1 Commonly Used Laboratory Equipment
1.1 Introduction
1.2 Digital Multi Meter (DMM)
1.3 Function Generator (Signal Generator)
1.4 Oscilloscope
1.5 Power Supply
1.6 Breadboard
1.7 Measurement with Cell Phone
1.8 Conventions Used in This Book
References for Further Study
2 Different Types of Switches
2.1 Introduction
2.2 Relay
2.3 Relay Test Circuit
2.4 Control of Relay with BJT Transistor
2.5 Control of Relay with MOSFET Transistor
2.6 Optocoupler
2.7 Control of Relay with an Optocoupler
2.8 Darlington Pair
2.9 MOSFET as Switch
2.10 Control of Load Current with Optocoupler and MOSFET Transistor
2.11 Temperature Switch
2.12 Reed Switch
2.13 Infrared Transmitter and Receiver
References for Further Study
3 Thyristors and Triacs
3.1 Introduction
3.2 Relaxation Oscillator with UJT
3.3 Thyristor
3.4 Thyristor Turn Off Methods in DC Circuits
3.5 Diac
3.6 Pulse Generation with Diacs
3.7 Dimmer Circuit
3.8 Controlled Rectifiers
References for Further Study
4 Power Supply Circuits
4.1 Introduction
4.2 Half Wave Rectifier
4.3 Full Wave Rectifier
4.4 Symmetric Power Supply
4.5 Voltage Regulator ICs
4.6 Regulated Power Supply with High Output Current and Short Circuit Protection
4.7 Regulator with Adjustable Output
4.8 Obtaining a High Regulated Output Voltage
4.9 Current Source Circuit
4.10 LM317 Adjustable Regulator
4.11 Overload Protection
4.12 Over Voltage Protection
4.13 Over Temperature Protection
4.14 Voltage Multiplier Circuit
4.15 Simple Inverter Circuit
References for Further Study
5 DC-DC Converters
5.1 Introduction
5.2 Boost Converter
5.3 Buck Converter
5.4 Voltage-Inverting Converter with TL7660 IC
5.5 Voltage-Inverting Converter with MC33063 IC
5.6 Voltage Inverting Converter with 555 IC
5.7 Voltage Doubler Circuit
References for Further Study
6 Filter and Comparator Circuits
6.1 Introduction
6.2 Simple Comparator
6.3 Window Comparator
6.4 Low Pass Filter
6.5 High Pass Filter
6.6 Band Pass Filter
References for Further Study
7 Control of DC Motors
7.1 Introduction
7.2 Direction of Rotation Indicator
7.3 DC Motor Speed Control
7.4 Control the Direction of Rotation
7.5 Full-Bridge Driver
7.6 Speed Control of Universal Motors
7.7 Stepper Motor and BLDC Motor Driver
References for Further Study
8 Delay Circuits
8.1 Introduction
8.2 Delay Circuit with Transistor (Normally on Circuit)
8.3 Delay Circuit with Transistor (Normally Off Circuit)
8.4 Delay Circuit with 555 IC
8.5 555 Timer IC Based Circuit Design
References for Further Study
Drawing Graphs with MATLAB®
A.1 Introduction
A.2 fplot Command
A.3 Plotting the Graph of a Numeric Data
A.4 Addition of Labels and Title to the Drawn Graph
A.5 Exporting the Drawn Graph as a Graphical File
A.6 Drawing Two or More Graphs on the Same Axis
A.7 Logarithmic Axis
Reference for Further Study

Citation preview

Synthesis Lectures on Electrical Engineering

Farzin Asadi

Industrial Electronic Circuits Laboratory Manual

Synthesis Lectures on Electrical Engineering

This series of short books covers a broad spectrum of titles of interest in electrical engineering that may not specifically fit within another series. Books will focus on fundamentals, methods, and advances of interest to electrical and electronic engineers.

Farzin Asadi

Industrial Electronic Circuits Laboratory Manual

Farzin Asadi Department of Electrical and Electronics Engineering Maltepe University Istanbul, Türkiye Department of Electrical and Electronics Engineering Beykent University Istanbul, Türkiye

ISSN 1559-811X ISSN 1559-8128 (electronic) Synthesis Lectures on Electrical Engineering ISBN 978-3-031-50772-4 ISBN 978-3-031-50773-1 (eBook) https://doi.org/10.1007/978-3-031-50773-1 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2024 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland Paper in this product is recyclable.

Preface

This is a book for a lab course meant to accompany, or follow, any standard course in industrial/power electronics. This book has the following objectives: 1. To support, verify, and supplement the theory; to show the relations and differences between theory and practice. 2. To teach measurement techniques. 3. To convince students that what they are taught in their lecture classes is real and useful. 4. To help make students tinkerers and make them used to asking “what if” questions. This book contains 50 experiments, which help the reader to explore the concepts studied in the classroom. It is assumed that the reader is familiar with the working principles of circuits. The references given at the end of chapters helps you to refresh your theoretical knowledge. Here is a brief summary of chapters and appendixes: Chapter 1 studies the most commonly used measurement devices that are used in the laboratory. Chapter 2 studies the most commonly used switches (i.e., relay, BJT, MOSFET, temperature, and reed switches). Chapter 3 studies the thyristor and triacs. Chapter 4 studies the different types of power supply circuits. Chapter 5 studies the DC-DC converter circuits. Chapter 6 studies the different types of filter and comparator circuits. Chapter 7 studies the speed and direction control of DC motors. Chapter 8 studies the delay generator circuits. Appendix shows how to draw different types of graphs with MATLAB® . I hope that this book will be useful to the readers, and I welcome comments on the book. Istanbul, Türkiye

Farzin Asadi

v

Contents

1 Commonly Used Laboratory Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Digital Multi Meter (DMM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 Function Generator (Signal Generator) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4 Oscilloscope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6 Breadboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7 Measurement with Cell Phone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.8 Conventions Used in This Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References for Further Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 1 1 2 3 5 6 9 13 14

2 Different Types of Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Relay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 Relay Test Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4 Control of Relay with BJT Transistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 Control of Relay with MOSFET Transistor . . . . . . . . . . . . . . . . . . . . . . . . . 2.6 Optocoupler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7 Control of Relay with an Optocoupler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.8 Darlington Pair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.9 MOSFET as Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.10 Control of Load Current with Optocoupler and MOSFET Transistor . . . 2.11 Temperature Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.12 Reed Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.13 Infrared Transmitter and Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References for Further Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

17 17 17 18 20 22 23 25 26 28 30 33 34 34 36

vii

viii

Contents

3 Thyristors and Triacs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 Relaxation Oscillator with UJT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3 Thyristor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4 Thyristor Turn Off Methods in DC Circuits . . . . . . . . . . . . . . . . . . . . . . . . 3.5 Diac . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.6 Pulse Generation with Diacs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.7 Dimmer Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.8 Controlled Rectifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References for Further Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

39 39 39 41 43 46 47 49 50 51

4 Power Supply Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 Half Wave Rectifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 Full Wave Rectifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.4 Symmetric Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5 Voltage Regulator ICs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6 Regulated Power Supply with High Output Current and Short Circuit Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.7 Regulator with Adjustable Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8 Obtaining a High Regulated Output Voltage . . . . . . . . . . . . . . . . . . . . . . . . 4.9 Current Source Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.10 LM317 Adjustable Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.11 Overload Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.12 Over Voltage Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.13 Over Temperature Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.14 Voltage Multiplier Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.15 Simple Inverter Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References for Further Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

53 53 53 53 54 57

5 DC-DC Converters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 Boost Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3 Buck Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4 Voltage-Inverting Converter with TL7660 IC . . . . . . . . . . . . . . . . . . . . . . . 5.5 Voltage-Inverting Converter with MC33063 IC . . . . . . . . . . . . . . . . . . . . . . 5.6 Voltage Inverting Converter with 555 IC . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.7 Voltage Doubler Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References for Further Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

77 77 77 78 79 79 80 81 82

60 61 61 63 64 64 66 67 68 71 75

Contents

ix

6 Filter and Comparator Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2 Simple Comparator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3 Window Comparator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4 Low Pass Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5 High Pass Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.6 Band Pass Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References for Further Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

85 85 85 85 88 92 93 98

7 Control of DC Motors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2 Direction of Rotation Indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3 DC Motor Speed Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.4 Control the Direction of Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5 Full-Bridge Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6 Speed Control of Universal Motors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.7 Stepper Motor and BLDC Motor Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . References for Further Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

101 101 101 101 102 103 106 107 108

8 Delay Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2 Delay Circuit with Transistor (Normally on Circuit) . . . . . . . . . . . . . . . . . 8.3 Delay Circuit with Transistor (Normally Off Circuit) . . . . . . . . . . . . . . . . 8.4 Delay Circuit with 555 IC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.5 555 Timer IC Based Circuit Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References for Further Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

111 111 111 112 113 114 117

Drawing Graphs with MATLAB® . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

119

1

Commonly Used Laboratory Equipment

1.1

Introduction

This chapter studies the most commonly used devices in the laboratory. Measurement devices that are used in different laboratories are made by different companies. Working with each device has its own details. Therefore, you are encouraged to read the user manual of devices that you will use during the experiments. Another good reference is your laboratory instructor. Studying the Ref. [1] is recommended as well.

1.2

Digital Multi Meter (DMM)

Digital multimeters are measuring instruments that can measure quantities such as voltage, current, and resistance. Measured values are shown on a digital display, allowing them to be read easily and directly, even by first-time users. Study the user manual of the DMM that you will use in the experiments. Ensure that you are able to do the followings: (a) (b) (c) (d)

Measurement Measurement Measurement Measurement

of of of of

resistance. AC/DC voltages. AC/DC currents in the range of Amps. AC/DC currents in the range of milli/micro Amps.

Ask your laboratory instructor to make an explanation to you if you are not able to do one or more of the above tasks.

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2024 F. Asadi, Industrial Electronic Circuits Laboratory Manual, Synthesis Lectures on Electrical Engineering, https://doi.org/10.1007/978-3-031-50773-1_1

1

2

1.3

1 Commonly Used Laboratory Equipment

Function Generator (Signal Generator)

A function generator (sometime is called signal generator) is used to generate different types of electrical waveforms over a wide range of frequencies. Some of the most common waveforms produced by the function generator are the sine wave, square wave, triangular wave and saw tooth shapes. The FG’s are divided into two groups: Analog FG’s and Direct Digital Synthesis (DDS) FG’s. As the name suggests, the analog FG’s, uses the analog circuits in order to produce the output waveform. DDS FG’s use digital circuits (i.e. a microprocessor) in order to produce the output waveforms. Accuracy of DDS signal generators is better than analog signal generators. Beside the standard waveforms (i.e. sinusoidal, square, triangular and saw tooth), some DDS FG’s are able to produce arbitrary waveforms. These type of FG’s are called Arbitrary Waveform Generator (AWG). They have software which permits you to draw the waveform that you want. After drawing the waveform in the software environment, the hardware of AWG produces the waveform for you. Output of function generator is connected to the circuit under test with the aid of a cable (Fig. 1.1). Black wire is connected to the ground of the signal generator as shown in Fig. 1.2. R1 shows the output resistance of the signal generator which is generally 50 Ω.

Fig. 1.1 Signal generator cable

1.4

Oscilloscope

3

Fig. 1.2 Simple model for signal generator

Study the user manual of the function generator that you will use in the experiments. Ensure that you are able to do the followings: (a) Generation of a sinusoidal signal with amplitude of 5 V and frequency of 50 Hz, i.e., v(t) = 5 × sin(2π × 50 × t) V. (b) Generation of a sinusoidal signal with amplitude of 5 V, frequency of 50 Hz and average value of 3 V, i.e., v(t) = 3 + 5 × sin(2π × 50 × t) V. (c) Generation of a sinusoidal signal with peak value of 50 mV, i.e., v(t) = 0.05 × sin(2π × 50 × t) V. (d) Generation of a triangular wave with frequency of 50 Hz and peak value of 5 V (Fig. 1.3). (e) Generation of a pulse with frequency of 50 Hz and duty cycle of 25% (Fig. 1.4). Ask your laboratory instructor to make an explanation to you if you are not able to do one or more of the above tasks.

1.4

Oscilloscope

An oscilloscope is an instrument that graphically displays electrical signals and shows how those signals change over time. Scientists, engineers, physicists, repair technicians and educators use oscilloscopes to see signals change over time. These days generally digital scopes are used in laboratory.

4

1 Commonly Used Laboratory Equipment

Fig. 1.3 Sample triangular wave

Fig. 1.4 Sample pulse

Study the user manual of the oscilloscope that you will use in the experiments. Ensure that you are able to do the followings: (a) (b) (c) (d) (e)

Measurement of peak value of a signal. Measurement of period and frequency of a periodic signal. Use the cursors to read voltage or time difference between two points. Observing two waveforms simultaneously. Measurement of phase difference between two waveforms. Remember that you can measure the phase difference between two waveform easily with the aid of Δϕ = Δt ◦ T × 360 formula (Fig. 1.5). (f) Explain the difference between AC and DC coupling. (g) Explain the functionality of X1/X10 switch on the probe.

1.5

Power Supply

5

◦ Fig. 1.5 Measurement of phase difference. B leads A by Δϕ = Δt T × 360

Ask your laboratory instructor to make an explanation to you if you are not able to do one or more of the above tasks.

1.5

Power Supply

All the circuits require an energy source in order to work. The power supply (PS) is responsible for providing the required energy for the circuit. The power supply takes the AC electric energy from the grid and converts it into a DC voltage. Generally, they provide the voltages in the 0–30 V range. Generally, the output current could be up to 3 A. The outputs of a PS are called a “Channel”. So, when we speak about a 3 channel PS, we mean a PS with three outputs. Generally, the outputs are variable and the user could set them to the desired value he/she wants. Generally, PS’s have one regulated output with voltage of 5 V. This output is used to supply digital circuits. Remember that traditional digital circuits work with 5 V (However this voltage decreased to 3.3 V and even 1.1 V these days!). So, it is a good idea to use this fixed 5 V when you work with traditional digital circuits. You can connect a digital circuit to variable outputs of a PS. However, if you increase the voltage of that variable channel by mistake, then your circuit may be damaged. So, always use this fixed 5 V when you are working with traditional digital circuits.

6

1 Commonly Used Laboratory Equipment

Study the user manual of the power supply that you will use in the experiments. Ensure that you are able to do the followings: (a) (b) (c) (d)

Generation of 12 V with maximum output current of 0.5 A. Generation of 12 V with maximum output current of 5 A (Use parallel mode). Generation of 40 V with maximum output current of 1 A (Use series mode). Generation of a symmetric voltage for instance +12 and −12 V with maximum output current of 0.5 A.

Ask your laboratory instructor to make an explanation to you if you are not able to do one or more of the above tasks.

1.6

Breadboard

A breadboard is used to build and test circuits quickly. The breadboard has many holes into which circuit components like ICs and resistors can be inserted. A typical breadboard is shown in Fig. 1.6. The breadboard has strips of metal which run underneath the board and connect the holes on the top of the board. The metal strips are laid out as shown below. Note that the

Fig. 1.6 Bead board

1.6

Breadboard

7

top and bottom rows of holes are connected horizontally while the remaining holes are connected vertically (Figs. 1.7 and 1.8). Let’s study an example. Assume that want to make the circuit shown in Fig. 1.9 on breadboard. Let’s start from the left side. Put the resistor R1 on the breadboard (Fig. 1.10).

Fig. 1.7 Connections of breadboard

Fig. 1.8 Inside of a breadboard

8

Fig. 1.9 Sample circuit

Fig. 1.10 Resistor R1 is added

1 Commonly Used Laboratory Equipment

1.7

Measurement with Cell Phone

9

Fig. 1.11 Resistor R2 is added

Put the resistor R2 (Fig. 1.11). Put the capacitor C1 (Fig. 1.12). Put the resistor R3 (Fig. 1.13). Connect the resistor R1 to the positive voltage rail and R2 and R3 to the negative voltage rail (Fig. 1.14). Connect the power supply to the breadboard (Fig. 1.15).

1.7

Measurement with Cell Phone

You can convert your cell phone, tablet or even your smart watch into a digital multimeter, digital storage oscilloscope (DSO) or a logger with the aid of Pokit meter (Figs. 1.16 and 1.17) or Pokit pro (Fig. 1.18). More information can be found on https://www.pokitinno vations.com/.

10

Fig. 1.12 Capacitor C1 is added

Fig. 1.13 Resistor R3 is added

1 Commonly Used Laboratory Equipment

1.7

Measurement with Cell Phone

Fig. 1.14 Power supply connection are made

Fig. 1.15 Voltage source is added to the circuit

11

12

Fig. 1.16 Pokit meter

Fig. 1.17 Pokit meter

1 Commonly Used Laboratory Equipment

1.8

Conventions Used in This Book

13

Fig. 1.18 Pokit pro

1.8

Conventions Used in This Book

In this book the symbols shown in Fig. 1.19 are used to show pass of two wires over each other without any connection. Figure 1.20 shows that two wires are connected to each other. Electrolytic capacitors are shown with the symbol shown in Fig. 1.21. Capacitance of the capacitor is shown behind the symbol. Polarity of the capacitor is shown in Fig. 1.22.

Fig. 1.19 There is no contact between w1 and w2 Fig. 1.20 There is a contact between w1 and w2

14

1 Commonly Used Laboratory Equipment

Fig. 1.21 Symbol used for electrolytic capacitors

Fig. 1.22 Polarity of electrolytic capacitor terminals

The terminal that is not hatched must be connected to the higher potential. The hatched terminal must be connected to the lower potential.

References for Further Study 1. Asadi F., Eguchi K., Electronic Measurement: A Practical Approach, Springer, 2021. 2. Asadi F., Power Electronics Circuit Analysis with PSIM® , De Gruyter, 2021. DOI: https://doi. org/10.1515/9783110740653 3. Asadi F., Simulation of Power Electronics Circuits with MATLAB® /Simulink® : Design, Analyze, and Prototype Power Electronics, Apress, 2022. DOI: https://doi.org/10.1007/978-1-48428220-5 4. Asadi F., Eguchi K., Simulation of Power Electronics Converters Using PLECS® , Academic Press, 2019. DOI: https://doi.org/10.1016/C2018-0-02253-7 5. Asadi F., Analog Electronic Circuits Laboratory Manual, Springer, 2023. DOI: https://doi.org/ 10.1007/978-3-031-25122-1 6. Asadi F., Electric Circuits Laboratory Manual, Springer, 2023. DOI: https://doi.org/10.1007/ 978-3-031-24552-7 7. Asadi F., Essential Circuit Analysis using NI Multisim™ and MATLAB® , Springer, 2022. DOI: https://doi.org/10.1007/978-3-030-89850-2

References for Further Study

15

8. Asadi F., Essential Circuit Analysis Using Proteus® , Springer, 2022. DOI: https://doi.org/10. 1007/978-981-19-4353-9 9. Asadi F., Essential Circuit Analysis using LTspice® , Springer, 2022. DOI: https://doi.org/10. 1007/978-3-031-09853-6 10. Asadi F., Electric and Electronic Circuit Simulation using TINA-TI® , River Publishers, 2022. DOI: https://doi.org/10.13052/rp-9788770226851 11. Asadi F., Electric Circuit Analysis with EasyEDA, Springer, 2022. DOI: https://doi.org/10.1007/ 978-3-031-00292-2

2

Different Types of Switches

2.1

Introduction

In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. Switches play an important role in industrial electronics. Important types of switches are studied in this chapter.

2.2

Relay

Relay is an electromechanical switch. You can use a relatively small current to control a large current. Relays are thousand and million times slower than electronic switches like BJT and MOSFET’s. Relays are bidirectional switches. Therefore, you can use them in both AC and DC circuits. Each relay has a coil. The current passes through the coil makes an electromagnet. The electromagnet closes or opens the relay’s contacts. Important types of relays are shown in Fig. 2.1. In Fig. 2.1, SPST, SPDT, DPST and DPDT stands for Single Pole Single Through, Single Pole Double Through, Double Pole Single Through and Double Pole Double Through, respectively. Each relay works with a certain voltage. The required operating voltage for the coil and current allowed to pass through relay contacts is printed on the relay case. For instance, for the relay shown in Fig. 2.2, the operating voltage for the coil is 12 V. The contacts of this relay can handle 250 VAC/10 A or 30 VDC/10 A load. Why the allowed DC voltage is much smaller than the allowed AC voltage?

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2024 F. Asadi, Industrial Electronic Circuits Laboratory Manual, Synthesis Lectures on Electrical Engineering, https://doi.org/10.1007/978-3-031-50773-1_2

17

18

2 Different Types of Switches

Fig. 2.1 Important types of relays

2.3

Relay Test Circuit

Circuit shown in Fig. 2.3 is a simple circuit to test a SPST relay. VDC equals to the nominal voltage of the relay coil. AC sinusoidal signal is large enough to turn on the light bulb. When you press the push button, the coil is energized and the lamp turns on. Test circuit for a SPDT relay is shown in Fig. 2.4. When the push button is not pressed, L1 is on and L2 is off. When you press the push button, L1 turns off and L2 turns on. VDC equals to the relay’s nominal coil voltage. AC sinusoidal signal is large enough to turn on the light bulb. Assume that the available DC voltage is bigger than the nominal voltage of the coil. You can use the circuit shown in Fig. 2.5 in this case. Let’s calculate the value of required resistor R1 in Fig. 2.5. When the push button V DC−Vr elay is pressed, the nominal current must pass through the coil. So, Inom = ⇒ R1 V DC−V

r elay R1 = . For instance, assume that we have a 12 V relay with coil resistance Inom 12 of 400 Ω. In this case nominal current is Inom = 400 = 30mA. When VDC = 15 V,

R1 =

V DC−Vr elay Inom

=

15−12 30

= 0.1 kΩ = 100 Ω (Fig. 2.6).

2.3

Relay Test Circuit

19

Fig. 2.2 A sample relay

Fig. 2.3 Simple test circuit for SPST relay

Make the circuits shown in Fig. 2.6 and ensure that it works as expected. Calculate the value of resistor R1 based on the relay that you used.

20

2 Different Types of Switches

Fig. 2.4 Simple test circuit for SPDT relay

Fig. 2.5 Using a series resistor to set the relay voltage

2.4

Control of Relay with BJT Transistor

You can use the circuit shown in Fig. 2.7 to control a relay with a microcontroller. The microcontroller pin generates 0 and 5 V (or 0 and 3.3 V). When the microcontroller pin is high, the transistor is in the saturation state and the relay coil is energized. When

2.4

Control of Relay with BJT Transistor

21

Fig. 2.6 Supplying a 12 V relay from a 15 V supply

microcontroller pin is 0 V, the transistor is in the cut-off state and coil is not energized and the pole is connected to normally close (NC) pin. Let’s design the circuit shown in Fig. 2.7. Assume that given relay is a 12 V relay with nominal current of 30 mA. This means that resistance of the coil is 400 Ω. TIP 41 is a good option for Q1. Let’s take the current equal to 40 (βmin = 40). Therefore,

Fig. 2.7 Control of a relay with a BJT transistor

22

2 Different Types of Switches

30 I B ≥ Inom mA40 = 750 μA. I B = 5−0.7 β = R1 ≥ 750 μA ⇒ R1 ≤ 5.73 kΩ. Note that I B shows the base current of Q1. Vrelay equals to 12 V since selected relay requires 12 V. Diode D1 protect the transistor Q1 against the voltage induced in the relay coil during the turn off time. Design the circuit shown in Fig. 2.7 based on relay available in your lab and test it. Use 0 and 5 V to test the circuit.

2.5

Control of Relay with MOSFET Transistor

You can use a MOSFET to control a relay as well. The circuit shown in Fig. 2.8 can be used for this purpose. Diode D1 protects the MOSFET against the induced voltage of relay coil. The microcontroller pin generates 0 and 5 V. When microcontroller generates 0 V, no current passes through the relay coil and the pole is connected to normally close terminal. When it generates 5 V, the coil is energized and connects the pole to normally open terminal. According to IRFZ 44 N datasheet, maximum of gate-source threshold voltage is 4 V. Therefore, 5 V can turn on the transistor since 5; V > max(V G S,thr eshold ) = 4 V.

Fig. 2.8 Control of a relay with a MOSFET transistor

2.6

Optocoupler

23

Fig. 2.9 A sample circuit to turn on/off a 12 V relay

Make the circuit shown in Fig. 2.9 and ensure it works properly. You can use NTD3055L170 MOSFET if your microcontroller generates 0 and 3.3 V. Maximum gate-source threshold voltage for NTD3055L170 equals to 2 V. Therefore, 3.3 V can turn on the NTD3055L170.

2.6

Optocoupler

Optocoupler (Opto-isolator) is device that transfer electrical signals between two isolates circuits with the aid of light. Generally, one of the isolated circuits works with a high voltage. We want to isolate this high voltage from the other circuit, which works with a low voltage and contains sensitive components like IC’s and transistors.

24

2 Different Types of Switches

Fig. 2.10 Simple test circuit for optocoupler

Let’s see how an optocoupler works. Prepare the circuit shown in Fig. 2.10. When the LED is not energized, the collector-emitter connection behaves like an open circuit and collector voltage equals to VCC which in Fig. 2.10 is 12 V. When the LED is energized, the collector-emitter behaves like short circuit and collector voltage is a small value. Apply the 0 and +5 V to the resistor R1 (Figs. 2.11 and 2.12) and measure the collector voltage. Does it work as expected? Measure the voltage drop across the LED in Fig. 2.12 as well. Search the internet and see what an optocounter is and how it works.

2.7

Control of Relay with an Optocoupler

25

Fig. 2.11 0 V is applied to resistor R1

2.7

Control of Relay with an Optocoupler

The optocoupler can be used in control of relays as well. The circuit shown in Fig. 2.13 can be used to turn on/off a light bulb. When control signal is +5 V the LED turns on and the phototransistor energizes the relay coil. When control signal is 0 V the LED is reverse biased and no current passes through the phototransistor. In this case the relay coil is not energized and the contacts are in the NC state. You can use the circuit shown in Fig. 2.14 if your relay requires more current than the maximum current of the optocoupler. When the LED is forward biased (control signal = +5 V), the phototransistor turns on and cause the Q1 to enter into the cut-off mode. The relay coil is not energized in this case and the relay contacts are in the NC state. When the LED is reverse biased (control signal = 0 V), the photo transistor is in the cut-off mode and Q1 is in the saturation mode. When Q1 is saturated, the relay’s coil is energized and the relay’s contacts are in the NO mode.

26

2 Different Types of Switches

Fig. 2.12 +5 V is applied to resistor R1

Make the circuits shown in Figs. 2.13 and 2.14 and ensure that they work as expected. Measure the voltage of different nodes for different values of control signal. Compare the measurements with hand analysis results.

2.8

Darlington Pair

The Darlington transistor named after its inventor, Sidney Darlington. Basic Darlington transistor configurations are shown in Fig. 2.15. Providing a high current gain is the advantage of the Darlington pair. Equivalent current gain for Darlington pair is around β1 ×β 2 where β1 and β2 shows the current gain of the first and second transistor. Note that we have two base emitter junction; therefore, a voltage drop of 1.4 V is expected. ULN2033 is a famous Darlington array.

2.8

Darlington Pair

Fig. 2.13 Control of a relay with optocoupler

Fig. 2.14 Sample test circuit to control a 12 V relay

27

28

2 Different Types of Switches

Fig. 2.15 Darlington pair

Let’s get started. Make the circuit shown in Fig. 2.16 (Use a 10 Ω, 10 W resistor as load). Set the VB equal to 0 V and start to increase it slightly. Pay attention to the value shown by the voltmeter. What is the minimum value shown by the voltmeter? Measure the circuit currents (base of Q1, collector of Q1, emitter of Q1, collector of Q2 and emitter of Q2) for VB = 10 V. Measure the voltage of base Q1 as well. Use the I +I measurements to calculate the equivalent current gain (βeq = C1I B1 C2 ). BDX 33 contains two transistors connected in Darlington configuration. You can use this device instead of using two discrete transistors.

2.9

MOSFET as Switch

MOSFET’s can be used as switches to connect or disconnect load current. The MOSFET turns on when you give a gate-source voltage which is bigger than the threshold voltage. Let’s get started. Make the circuit shown in Fig. 2.17. Increase the VG from 0 to 5 V with 0.5 steps. Pay attention to the collector voltage. Find the minimum value that turns on the MOSFET.

2.9

MOSFET as Switch

29

Fig. 2.16 Control of a load with a Darlington pair

You can control the load power with the aid of pulses applied to the gate terminal of the MOSFET. Make the circuit shown in Fig. 2.18 and apply pulses with different duty cycles to the gate terminal (Fig. 2.19). Observe the output (drain voltage) and input (gate voltage) simultaneously. What is the relationship between input and output? Use the oscilloscope to measure the RMS of load voltage. Use the RMS value to find the power dissipated in the load. You can use the circuit shown in Fig. 2.20 to control the speed of small DC motors. The diode protects the transistor against the high voltages generated by armature winding. Make the circuit shown in Fig. 2.20 and apply a gate pulse with duty cycle of 20% and frequency of 500 Hz (Fig. 2.21). Increase the duty cycle from 20% up to 80% with 10% steps and observe the change of DC motor speed. You can use the TL 494 to control the speed of small DC motors as well. TL 494 generates the required pulses for you and eliminates the need for a signal generator.

30

2 Different Types of Switches

Fig. 2.17 Measurement of threshold voltage of the MOSFET

2.10

Control of Load Current with Optocoupler and MOSFET Transistor

The circuit shown in Fig. 2.22 can be used to control a load current. Vload is the voltage required for the load. When control signal is +5 V, the LED is forward biased and the phototransistor is in saturation mode. Q1 is reverse biased and Q2 charges the gate-source capacitor of the MOSFET. This turns on the MOSFET and load current starts to flow. Diode D1 protects the MOSFET against the inductive loads. When control signal is 0 V, the LED is reverse biased and the phototransistor is cut-off mode. Q1 conducts and cause Q3 to discharge the gate-source capacitor of the MOSFET. This turns off the MOSFET and load current stops.

2.10

Control of Load Current with Optocoupler and MOSFET Transistor

Fig. 2.18 Control of a load with a MOSFET

Fig. 2.19 Frequency of these pulses is 10 kHz

31

32

2 Different Types of Switches

Fig. 2.20 Speed control of a DC motor with a MOSFET

Fig. 2.21 Gate pulses

Make the circuit shown in Fig. 2.22. Use a 10 Ω resistor as load (Vload = 12 V). Give different control signals to the circuit and observe its behavior. Measure the DC voltage of different nodes and compare them with your hand analysis results.

2.11 Temperature Switch

33

Fig. 2.22 Control of a load with an optocoupler and MOSFET

2.11

Temperature Switch

Temperature switches (thermostats) are a type of switches that change state based on the temperature. Temperature switches are divided into two groups: (A) Contact opens when temperature rises to set point (Normally Closed), (B) Contact closes when temperature rises to set point (Normally Open). Two type of temperature switches are shown in Figs. 2.23 and 2.24. Let’s get started. Make the circuit shown in Fig. 2.25 with the temperature switch you have in the lab. Use a soldering iron to increase the temperature of the temperature

Fig. 2.23 Sample temperature switches

34

2 Different Types of Switches

Fig. 2.24 Sample temperature switch

switch and see what happens. Then remove the soldering iron and permit the sensor to start cooling down. What happens in this case?

2.12

Reed Switch

The reed switch is an electromechanical switch operated by an applied magnetic field. It can be used to turn on/off a device based on presence/absence of a magnetic field. When magnetic field exists, the reed switch acts as short circuit. When magnetic field does not exist, it act as open circuit. Let’s get started. Make the circuit shown in Fig. 2.26. Bring a magnet close to the reed switch and observe what happens.

2.13

Infrared Transmitter and Receiver

You can use infrared transmitter and receiver (Figs. 2.27 and 2.28) to turn on or off a devices. For instance, hand dryers use these type of sensors in order to detect whether user hand is put in front of the device. Infrared transmitter and receivers are Arduino compatible. Therefore, you can use an Arduino board to read them [1].

2.13

Infrared Transmitter and Receiver

Fig. 2.25 Test circuit for temperature switch

Fig. 2.26 Test circuit for reed switch

35

36

2 Different Types of Switches

Fig. 2.27 A sample of infrared transmitter and receiver

Fig. 2.28 A sample of infrared transmitter and receiver

References for Further Study 1. Asadi F., Essential of Arduino Boards Programming: Step-by-Step Guide to Master Arduino Boards Hardware and Software, Apress, 2023, DOI: https://doi.org/10.1007/978-1-4842-9600-4 2. Mohan N., Undeland T., Robbins W., Power Electronics: Converters, Applications, and Design, Wiley, 2007.

References for Further Study

37

3. Asadi F., Power Electronics Circuit Analysis with PSIM® , De Gruyter, 2021. DOI: https://doi. org/10.1515/9783110740653 4. Asadi F., Simulation of Power Electronics Circuits with MATLAB® /Simulink® : Design, Analyze, and Prototype Power Electronics, Apress, 2022. DOI: https://doi.org/10.1007/978-1-48428220-5 5. Asadi F., Eguchi K., Simulation of Power Electronics Converters Using PLECS® , Academic Press, 2019. DOI: https://doi.org/10.1016/C2018-0-02253-7 6. Asadi F., Analog Electronic Circuits Laboratory Manual, Springer, 2023. DOI: https://doi.org/ 10.1007/978-3-031-25122-1 7. Asadi F., Electric Circuits Laboratory Manual, Springer, 2023. DOI: https://doi.org/10.1007/ 978-3-031-24552-7 8. Asadi F., Essential Circuit Analysis using NI Multisim™ and MATLAB® , Springer, 2022. DOI: https://doi.org/10.1007/978-3-030-89850-2 9. Asadi F., Essential Circuit Analysis Using Proteus® , Springer, 2022. DOI: https://doi.org/10. 1007/978-981-19-4353-9 10. Asadi F., Essential Circuit Analysis using LTspice® , Springer, 2022. DOI: https://doi.org/10. 1007/978-3-031-09853-6 11. Asadi F., Electric and Electronic Circuit Simulation using TINA-TI® , River Publishers, 2022. DOI: https://doi.org/10.13052/rp-9788770226851 12. Asadi F., Electric Circuit Analysis with EasyEDA, Springer, 2022. DOI: https://doi.org/10.1007/ 978-3-031-00292-2 13. Asadi F., Eguchi K., Electronic Measurement: A Practical Approach, Springer, 2021. DOI: https://doi.org/10.1007/978-3-031-02021-6 14. https://bit.ly/3KPtUUR

3

Thyristors and Triacs

3.1

Introduction

Thyristor (or Silicon Controlled Rectifier, SCR) is an important solid-state switch. It is a unidirectional device. This means that current can pass from anode to cathode only (Fig. 3.1). Triacs (Fig. 3.2) are bidirectional switches (current can go from MT1 to MT2 or from MT2 to MT1). Being bidirectional makes triacs suitable for AC circuits. This chapter studies the important circuits that can be made with thyristors and triacs.

3.2

Relaxation Oscillator with UJT

Relaxation oscillator is the most common use of Uni-Junction Transistor (UJT). The relaxation oscillator can be used to trigger the thyristors. A relaxation oscillator is shown in Fig. 3.3. Explain how the circuit shown in Fig. 3.3 works. Make the circuit shown in Fig. 3.3 and observe the waveform of different nodes. What role is played by the potentiometer? Observe the voltage of Emitter node (node E in Fig. 3.3) and measure the maximum and minimum value of the observed waveform. For 2N2646, typical intrinsic standoff ratio (η) is around 0.7. Therefore, peak value of Emitter voltage is around V p = η·VB B +VD = 0.7 × 12 + 0.7 = 9.1V.

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2024 F. Asadi, Industrial Electronic Circuits Laboratory Manual, Synthesis Lectures on Electrical Engineering, https://doi.org/10.1007/978-3-031-50773-1_3

39

40 Fig. 3.1 Thyristor symbol

Fig. 3.2 Triac symbol

3 Thyristors and Triacs

3.3 Thyristor

41

Fig. 3.3 Relaxation oscillator with UJT

3.3

Thyristor

Thyristor is a unidirectional switch (Fig. 3.4). The user can apply a gate pulse to turn on the thyristor. When the thyristor is on, the current goes from anode to cathode. The thyristor conducts current until the voltage between the cathode and anode is reversed or reduced below a certain threshold or holding value. Circuits of this chapter used TIC106 thyristor. Pinout of TIC106 thyristor is shown in Fig. 3.5.

42

3 Thyristors and Triacs

Fig. 3.4 In thyristors current flows from anode to cathode

Thyristors are operated in one of the following three states. Forward conducting: This is a thyristor’s primary operating mode. Current flows from anode to cathode until the current falls below a specific level, called the holding current. Forward blocking: In this case Vanode − Vcathode > 0. However, lack of gate pulse causes the thyristor block the flow of current. Reverse blocking mode: In this case Vanode − Vcathode < 0 and no current (except of a small leakage current of order of few micro amps) pass through the thyristor. Let’s get started. Circuit shown in Fig. 3.6 helps you to understand how thyristor works. Make the circuit shown in Fig. 3.6 (Set VG to 0 V). Use a DC voltmeter to monitor the load voltage (i.e., V A − VB ). Increase the VG slightly until the thyristor enters the forward conducting mode (when DC voltmeter shows a voltage around 10–10.5 V the thyristor is in the forward conducting mode). Measure the gate current (current through resistor RG) and voltage drop across the anode–cathode of the thyristor. Disconnect the connection between RG and gate terminal (Fig. 3.7) when the thyristor is in the forward conduction mode. Does the thyristor continue to conduct current in this case?

3.4 Thyristor Turn Off Methods in DC Circuits

43

Fig. 3.5 Pins of TIC106 thyristor

3.4

Thyristor Turn Off Methods in DC Circuits

Consider the circuit shown in Fig. 3.8. When you press the S1 push button, the thyristor starts to conduct current and enters the forward conduction mode. When you press the S2 push button, the load current starts to pass through the push button S2 and thyristor current decreases to zero. When you release the push button S2, the thyristor is in the off state and stays in the off state until the user press the push button S1 again.

44

3 Thyristors and Triacs

Fig. 3.6 Simple test circuit for a thyristor

Make the circuit shown in Fig. 3.8 and ensure that it works as expected. Press the push button S1 and measure the voltage of different nodes. Release the push button S1 after measurement. Then press the push S2 and measure the voltage of different nodes. Compare your measurements with hand analysis results. Another technique to turn off a thyristor in a DC circuit is shown in Fig. 3.9. When you press the S1 push button, the gate current flows and the thyristor enters the forward conduction mode. This charges the capacitor C1 to around 10–10.5 V.

3.4 Thyristor Turn Off Methods in DC Circuits

45

Fig. 3.7 Gate current is zero

When you press the S2 push button, the capacitor is connected to the thyristor and applies a negative voltage it. This negative voltage cause the thyristor to enter the reverse blocking mode and stops the load current. Make the circuit shown in Fig. 3.9. Press the push button S1 and measure the voltage of different nodes. Release the push button S1 after measurement. Then press the push S2 and measure the voltage of different nodes. Compare your measurements with hand analysis results.

46

3 Thyristors and Triacs

Fig. 3.8 Turning off the thyristor with a switch

3.5

Diac

The diac is a diode that conducts electrical current only after its break over voltage, VBO, has been reached momentarily. I-V characteristic of a diac is shown in Fig. 3.10. Diacs are usually used for triggering the triacs. Let’s use a simple circuit to see how diacs behave. Make the circuit shown in Fig. 3.11. Set V1 equal to 0 V and increase it with 3 V steps until the LED turns on (V 1 ≈ 30V turns on the LED). Measure the voltage drop across the diac when the LED is turned on.

3.6

Pulse Generation with Diacs

47

Fig. 3.9 Turning off the thyristor by applying a negative voltage to anode–cathode

Repeat the previous experiment with the polarity of V1 reversed (Fig. 3.12).

3.6

Pulse Generation with Diacs

You can use the diacs for pulse generation as well. Consider the circuit shown in Fig. 3.13. The capacitor starts to charge through R1 and potentiometer. When voltage of capacitor wants to go over the break over voltage of DB3 diac, the diac enters the conduction mode and discharges the capacitor. Capacitor starts to charge again after the discharge and this process repeats.

48

3 Thyristors and Triacs

Fig. 3.10 Typical current–voltage (I-V) curve for a diac

Fig. 3.11 Simple circuit to test the behavior of a diac

Make the circuit shown in Fig. 3.13. Use an oscilloscope to observe the waveforms of node A and B. What is the effect of potentiometer on circuit waveforms?

3.7

Dimmer Circuit

49

Fig. 3.12 Applying negative voltages to the diac

3.7

Dimmer Circuit

A dimmer circuit is a circuit which can be used to control the intensity of incandescent light bulbs, speed of small universal motors or amount of heat generated by a heater. A dimmer works by essentially chopping parts out of the AC voltage. A dimmer circuit is shown in Fig. 3.14. The triac is triggered when voltage of capacitor C1 is bigger than the break over voltage of DB3 diac. Break over voltage of DB3 is around 30 V. The time instant that capacitor voltage reaches 30 V is controlled by potentiometer and its series resistor R1. R2 and C2 form a snubber circuit and protest the triac. Simulate the circuit shown in Fig. 3.14 and observe the waveforms of different nodes. Study the effect of potentiometer on the load voltage. Don’t try to make this circuit on breadboard. Realization of this circuit requires a printed circuit board and it must be tested under the supervision of lab instructor.

50

3 Thyristors and Triacs

Fig. 3.13 Pulse generation with diac

3.8

Controlled Rectifiers

Thyrsitors can be used to make controlled rectifiers. Controlled rectifiers generally use a pulse transformer to trigger the thyristors. Reference [1] shows how to make a controlled rectifier with thyristors and an Arduino board.

References for Further Study

51

Fig. 3.14 Dimmer circuit

References for Further Study 1. bit.ly/3sq9UBL 2. Mohan N., Undeland T., Robbins W., Power Electronics: Converters, Applications, and Design, Wiley, 2007. 3. Asadi F., Power Electronics Circuit Analysis with PSIM® , De Gruyter, 2021. DOI: https://doi. org/10.1515/9783110740653 4. Asadi F., Simulation of Power Electronics Circuits with MATLAB® /Simulink® : Design, Analyze, and Prototype Power Electronics, Apress, 2022. DOI: https://doi.org/10.1007/978-1-48428220-5 5. Asadi F., Eguchi K., Simulation of Power Electronics Converters Using PLECS® , Academic Press, 2019. DOI: https://doi.org/10.1016/C2018-0-02253-7 6. Asadi F., Analog Electronic Circuits Laboratory Manual, Springer, 2023. DOI: https://doi.org/ 10.1007/978-3-031-25122-1 7. Asadi F., Electric Circuits Laboratory Manual, Springer, 2023. DOI: https://doi.org/10.1007/ 978-3-031-24552-7 8. Asadi F., Essential Circuit Analysis using NI Multisim™ and MATLAB® , Springer, 2022. DOI: https://doi.org/10.1007/978-3-030-89850-2 9. Asadi F., Essential Circuit Analysis Using Proteus® , Springer, 2022. DOI: https://doi.org/10. 1007/978-981-19-4353-9 10. Asadi F., Essential Circuit Analysis using LTspice® , Springer, 2022. DOI: https://doi.org/10. 1007/978-3-031-09853-6

52

3 Thyristors and Triacs

11. Asadi F., Electric and Electronic Circuit Simulation using TINA-TI® , River Publishers, 2022. DOI: https://doi.org/10.13052/rp-9788770226851 12. Asadi F., Electric Circuit Analysis with EasyEDA, Springer, 2022. DOI: https://doi.org/10.1007/ 978-3-031-00292-2 13. Asadi F., Eguchi K., Electronic Measurement: A Practical Approach, Springer, 2021. DOI: https://doi.org/10.1007/978-3-031-02021-6

4

Power Supply Circuits

4.1

Introduction

All of the electronic circuits require an energy source to operate correctly. This chapter studies different types of power supplies.

4.2

Half Wave Rectifier

A half wave rectifier circuit is shown in Fig. 4.1. The transformer used is a 12 V transformer (Fig. 4.2). Capacitor C1 is 1000 µF, 35 V. Make the circuit shown in Fig. 4.1. Use an oscilloscope to observe the load voltage waveform. Use AC coupling of the oscilloscope to observe the load voltage ripple. Measure the frequency and peak-to-peak value of ripple voltage. Compare the measured values with hand analysis results. What is the relationship between ripple voltage frequency and frequency of input AC source? Use a DC voltmeter to measure the average value of load voltage. What is the relationship between peak value of secondary voltage and average value of load voltage?

4.3

Full Wave Rectifier

A full wave rectifier circuit is shown in Fig. 4.3. The transformer used is a 12 V transformer (Fig. 4.2). Capacitor C1 is 1000 µF, 35 V. Make the circuit shown in Fig. 4.3. Use an oscilloscope to observe the load voltage waveform. Use AC coupling of the oscilloscope to observe the load voltage ripple. Measure the frequency and peak-to-peak value of ripple voltage. Compare the measured values with hand analysis results. What is the relationship between ripple voltage frequency and frequency of input AC source? Use

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2024 F. Asadi, Industrial Electronic Circuits Laboratory Manual, Synthesis Lectures on Electrical Engineering, https://doi.org/10.1007/978-3-031-50773-1_4

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4 Power Supply Circuits

Fig. 4.1 Half wave rectifier

Fig. 4.2 RMS of the output voltage is 12 V

a DC voltmeter to measure the average value of load voltage. What is the relationship between peak value of secondary voltage and average value of load voltage? What is the difference between full wave and half wave rectifier? You can use a diode bridge instead of using four separate diode. A sample diode bridge and its equivalent circuit are shown in Figs. 4.4 and 4.5, respectively.

4.4

Symmetric Power Supply

The previous circuits provides positive voltages only. In this section, we want to study the generation of symmetric outputs (i.e., both positive and negative voltages). Symmetric power supplies require a center tap transformer. The transformer required in this section is shown in Fig. 4.6. Waveforms of this transformer are shown in Fig. 4.7.

4.4

Symmetric Power Supply

Fig. 4.3 Full wave rectifier Fig. 4.4 Diode bridge

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4 Power Supply Circuits

Fig. 4.5 Schematic of a diode bridge

Fig. 4.6 Center tap transformer with 12 V output

The circuit shown in Fig. 4.8 can be used for generation of symmetric voltages. Capacitor C1 and C2 are 1000 µF, 35 V. Make the circuit shown in Fig. 4.8. Use an oscilloscope to observe the load1 voltage waveforms. Use AC coupling of the oscilloscope to observe the load1 voltage ripple. Measure the frequency and peak-to-peak value of ripple voltage. Compare the measured values with hand analysis results. What is the relationship between ripple voltage frequency and frequency of input AC source? Use a DC voltmeter to measure the average value of load1 voltage. What is the relationship between peak value of secondary voltage and average value of load1 voltage? Repeat the measurements for load2 as well.

4.5 Voltage Regulator ICs

57

Fig. 4.7 Output voltage of center tap transformer

Fig. 4.8 Power supply circuit with positive and negative voltages

4.5

Voltage Regulator ICs

Voltage regulators provide an accurate constant voltage for you. A +5 V voltage regulator IC is shown in Fig. 4.9. 78xx and 79xx ICs are among the commonly used voltage regulator ICs. 78xx voltage regulator ICs produce positive fixed DC voltage values, whereas, 79xx voltage regulator ICs produce negative fixed DC voltage values. For example, 7805 provides a +5 V output

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4 Power Supply Circuits

Fig. 4.9 A +5 V voltage regulator IC

while 7905 provides a −5 V output. Pinout 78xx and 79xx ICs are shown in Fig. 4.10. For correct operation, absolute value of input voltage must be bigger than output voltage by at least 2–3 V. The circuit shown in Fig. 4.11 shows how to convert +12 V into +5 V. 7805 can take input voltages in the [+7 V, +35 V] range and can give up to 1.5 A of output current. Addition of a diode between input and output nodes (Fig. 4.12) is recommended. The circuit shown in Fig. 4.13 shows how to convert −12 V into −5 V. 7905 can take input voltages in the [−7 V, −35 V] range and can give up to 1 A of output current. Addition of a diode between input and output nodes (Fig. 4.14) is recommended. The circuit shown in Fig. 4.15 is a regulated ±5 V power supply. Make the circuits shown in Figs. 4.12, 4.14 and 4.15. Measure the output voltages and ensure that they are as expected.

4.5 Voltage Regulator ICs

Fig. 4.10 Pinout of 78xx and 79xx ICs

Fig. 4.11 Sample circuit with 7805

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Fig. 4.12 Addition of diode D1 is recommended

Fig. 4.13 Sample circuit with 7905

4.6

Regulated Power Supply with High Output Current and Short Circuit Protection

Output current of 78xx ICs is limited to 1.5 A. You can use the circuit shown in Fig. 4.16 to obtain more output current. Circuit shown in Fig. 4.16 is a regulated power supply with high output current and short circuit protection. Short circuit current for Fig. 4.16 is V I SC = RB ESCQ2 ≈ R0.6 . SC Make the circuit shown in Fig. 4.17. This circuit provides a +5 V output for the load V 0.6 = 2.73A (Note that 7805 and output current is limited to around I SC = RB ESCQ2 ≈ 0.22 can handle up to 1.5 A only). Use a DC ammeter to measure the Iload , I1 and I2 . Then measure the short circuit current of the output and compare it with calculated value of ×Iin 2.73A. Calculate the efficiency of this circuit (Remember that η = PPout = R Vin×I 2 ). in Load

Load

4.8

4.7

Obtaining a High Regulated Output Voltage

61

Regulator with Adjustable Output

The circuit shown in Fig. 4.18 can be used to obtain a variable output voltage. Formula for output voltage is shown in Fig. 4.18. This formula is correct when I R1 > 5I Q . Let’s get started. Make the circuit shown in Fig. 4.19. Measure the minimum and maximum output voltages that this circuit can generate. Use a DC milli ammeter to measure the I Q as well. Measure the output value for the case R1 = 3kΩ and R2 = 7kΩ.

4.8

Obtaining a High Regulated Output Voltage

You can use the circuit shown in Fig. 4.20 to obtain a high regulated output voltage. Formula for output voltage is shown in Fig. 4.20. This formula is correct when I R1 ≥ 5I Q . Remember that for correct operation, absolute value ( of input ) voltage must be bigger than R2 output voltage by at least 2–3 V, i.e., Vin − V X X 1 + R1 + I Q R2 > 3V . Let’s get started. Make the circuit shown in Fig. 4.21 and measure the output voltoutput with value predicted by the VO = age and ( I Q and ) I R1 . Compare (the measured ) R2 390 V X X 1 + R1 + I Q R2 = 24 × 1 + 470 + I Q × 390 = 43.91 + I Q × 390 formula. The circuit shown in Fig. 4.22 can be used to generate +5, 6.5, 8.3, 9.9 and 12 V. Make the circuit shown in Fig. 4.22 and ensure that it gives the expected output voltages.

Fig. 4.14 Addition of diode D1 is recommended

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Fig. 4.15 A power supply circuit with positive and negative regulated output voltages

Fig. 4.16 Increasing the output current and protection against short circuit

Fig. 4.17 Test circuit

4.9

Current Source Circuit

63

Fig. 4.18 Obtaining a variable output voltage

Fig. 4.19 Test circuit

4.9

Current Source Circuit

The circuit shown in Fig. 4.23 can be used as current source. Remember that for correct operation, absolute value (of input voltage must be bigger than output voltage by at least ) VX X 2–3 V, i.e., Vin − V X X − R1 + I Q Rload > 3V. Let’s get started. The circuit shown in Fig. 4.24 can be approximated as a 5/47 = 106 mA current source. Make the circuit shown in Fig. 4.24. Connect different loads in the [0 Ω, 120 Ω] range to the output and pay attention to value read by the milli ammeter.

64

4.10

4 Power Supply Circuits

LM317 Adjustable Regulator

LM317 is one of the commonly used voltage regulators. An adjustable voltage regulator with LM317 is)shown in Fig. 4.25. Output voltage for this circuit is given by: VO = ( 1.25× 1 + RR21 +(Iad j × R2 ).Iad j is typically 50 µA and negligible in most applications. Make the circuit shown in Fig. 4.26. Measure the maximum and minimum value of load Compare the measured values with values predicted using the VO ≈ 1.25 × ) ( voltage. 1 + RR21 formula.

4.11

Overload Protection

The circuit shown in Fig. 4.27 can be used to avoid drawing currents beyond a certain V E,Q1 limit. When current drawn from the input source exceeds Imax = BR1 ≈ 0.6 R1 , the transistor Q1 turns on. This turns on the thyristor as well. The relay is activated and disconnects the load current when the thyristor turns on. When load current is disconnected, the LED turns on to inform the user. After solving the problem, the user needs to press the normally close push button to reset the circuit.

Fig. 4.20 Obtaining a high output voltage

4.11

Overload Protection

65

Fig. 4.21 Test circuit

Fig. 4.22 Obtaining +5, 6.5, 8.3, 9.9 and 12 V at the output

The reset push button can be placed in parallel with the thyristor as well (Fig. 4.28). Note that the push button in Fig. 4.28 is a normally open push button. When overload happens, you need to press the push button to reset the circuit.

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4 Power Supply Circuits

Fig. 4.23 Current source circuit

Let’s get started. Make the circuit shown in Fig. 4.29. Decrease the value of load resistor from 50 Ω toward 20 Ω and measure the maximum current that can be drawn from V E,Q1 ≈ the source. Compare your measurement with value predicted by the Imax = BR1 0.6 0.6 = = 0.6A formula. R1 1 Protection against short circuit using relays is studied in [1].

4.12

Over Voltage Protection

The circuit shown in Fig. 4.30 can be used for overvoltage protection purposes. The thyristor turns on when input voltage is big enough. You need to press the push button to reset the circuit. Similar to the previous circuit, you can connect the reset push button in parallel with the thyristor (Fig. 4.31). Make the circuit shown in Fig. 4.30 or 4.31. Apply VIN = 6 V and VIN = 15 V to the circuit and see what happens. Set the VIN = 0, then increase the VIN slightly and measure the maximum input voltage that can be applied to the load.

4.13

Over Temperature Protection

67

Fig. 4.24 Test circuit

4.13

Over Temperature Protection

The circuit shown in Fig. 4.32 or 4.33 can be used to disconnect the energy from a load when temperature is beyond a certain level. When temperature rises, the NTC resistance decreases and potential of positive terminal of Op Amp increases. Output of the Op Amp 8.2 × 12 = is low (i.e., around 0 V) when potential of positive terminal is less than 8.2+4.7 7.63 V. Output of the Op Amp is high (i.e., around 12 V) when voltage of positive terminal of the Op Amp is bigger than 7.63 V. The thyristor is triggered when output of the Op Amp is high. The user needs to press the push button to reset the circuit.

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4 Power Supply Circuits

Fig. 4.25 Adjustable regulator with LM317

Make the circuit shown in Fig. 4.32 or 4.33. Use a soldering iron to heat the NTC and observe the circuit behavior. At which temperature the circuit current is stopped? Use hand analysis to obtain a relationship for current cut-off temperature of the circuit.

4.14

Voltage Multiplier Circuit

Voltage doubler and tripler circuits are shown in Figs. 4.34 and 4.35, respectively. These circuits can’t provide much current and are used in low current applications. Use a hand analysis and show that Figs. 4.34 and 4.35 are voltage doubler and tripler. Make the circuit shown in Figs. 4.34 and 4.35 (the transformer secondary voltage is 12 VAC and working voltage of the capacitors is 63 V). Use a DC voltmeter to measure the voltage of capacitors and compare them with your hand analysis.

4.14 Voltage Multiplier Circuit

Fig. 4.26 Test circuit

Fig. 4.27 Overload protection circuit (Reset button is in series with VIN source)

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4 Power Supply Circuits

Fig. 4.28 Overload protection circuit (Reset button is in parallel with the thyristor)

Fig. 4.29 Test circuit

4.15

Simple Inverter Circuit

71

Fig. 4.30 Over voltage protection circuit (Reset button is in series with VIN source)

4.15

Simple Inverter Circuit

The circuit shown in Fig. 4.36 is a simple inverter (i.e., DC to AC converter) circuit. Q2 and Q3 are switched with frequency of 50 Hz. The transformer used here is shown in Fig. 4.2. Gate pulses applied to Q2 and Q3 are complement of each other. Let’s get started. Explain how circuit shown in Fig. 4.36 works. Simulate the circuit shown in Fig. 4.36. Observe the gate pulses of Q2 and Q3. Use an oscilloscope to observe the load voltage waveform. Change the value of load and see its effect on the load voltage. Ready to use EGS002 card can be used to make more accurate SPWM inverters [2].

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4 Power Supply Circuits

Fig. 4.31 Over voltage protection circuit (Reset button is in parallel with the thyristor)

Fig. 4.32 Over temperature protection circuit (Reset button is in series with VIN source)

4.15

Simple Inverter Circuit

Fig. 4.33 Over temperature protection circuit (Reset button is in parallel with the thyristor)

Fig. 4.34 Voltage doubler circuit

Fig. 4.35 Voltage tripler circuit

73

Fig. 4.36 Simple square wave inverter circuit

74 4 Power Supply Circuits

References for Further Study

75

References for Further Study 1. 2. 3. 4. 5. 6. 7. 8.

9. 10. 11. 12. 13. 14. 15. 16. 17.

https://bit.ly/3QTtyAi https://bit.ly/3skFFwp https://bit.ly/3KLcpF6 https://bit.ly/45x1t67 https://bit.ly/45v9s4d Mohan N., Undeland T., Robbins W., Power Electronics: Converters, Applications, and Design, Wiley, 2007. Asadi F., Power Electronics Circuit Analysis with PSIM® , De Gruyter, 2021. DOI: https://doi. org/10.1515/9783110740653 Asadi F., Simulation of Power Electronics Circuits with MATLAB® /Simulink® : Design, Analyze, and Prototype Power Electronics, Apress, 2022. DOI: https://doi.org/10.1007/978-1-48428220-5 Asadi F., Eguchi K., Simulation of Power Electronics Converters Using PLECS® , Academic Press, 2019. DOI: https://doi.org/10.1016/C2018-0-02253-7 Asadi F., Analog Electronic Circuits Laboratory Manual, Springer, 2023. DOI: https://doi.org/ 10.1007/978-3-031-25122-1 Asadi F., Electric Circuits Laboratory Manual, Springer, 2023. DOI: https://doi.org/10.1007/ 978-3-031-24552-7 Asadi F., Essential Circuit Analysis using NI Multisim™ and MATLAB® , Springer, 2022. DOI: https://doi.org/10.1007/978-3-030-89850-2 Asadi F., Essential Circuit Analysis Using Proteus® , Springer, 2022. DOI: https://doi.org/10. 1007/978-981-19-4353-9 Asadi F., Essential Circuit Analysis using LTspice® , Springer, 2022. DOI: https://doi.org/10. 1007/978-3-031-09853-6 Asadi F., Electric and Electronic Circuit Simulation using TINA-TI® , River Publishers, 2022. DOI: https://doi.org/10.13052/rp-9788770226851 Asadi F., Electric Circuit Analysis with EasyEDA, Springer, 2022. DOI: https://doi.org/10.1007/ 978-3-031-00292-2 Asadi F., Eguchi K., Electronic Measurement: A Practical Approach, Springer, 2021. DOI: https://doi.org/10.1007/978-3-031-02021-6

5

DC-DC Converters

5.1

Introduction

DC-DC converters take a DC voltage as input and generate a different DC voltage (i.e., a DC voltage that is bigger or smaller than input) as output. This chapter studies some of the important DC-DC converter circuits.

5.2

Boost Converter

The circuit shown in Fig. 5.1 shows a Boost converter circuit. The Boost converter provides a output voltage that is bigger than input voltage. The gate signal is a pulse with amplitude of 5 V, frequency of 25 kHz and duty cycle of 0.6. You can use a signal generator to make this pulse. Analyze the circuit shown in Fig. 5.1 and calculate the average value of output voltage and output voltage ripple using hand analysis. Make the circuit and measure the average value of output voltage using a DC voltmeter. Then use an oscilloscope to measure the output voltage ripple (connect the oscilloscope to load and use AC coupling to observe the ripple only). Compare your measurements with hand analysis results. Calculate the ). Change the duty cycle and measure the average efficiency of the circuit as well (η = PPout in value of output for different duty cycles. A DC-DC converter requires a closed-loop control system to give a stable DC output. Without a closed-loop control system, disturbances like: input voltage changes and output load changes affect the output voltage. Closed-loop control system design for DC-DC converters is studied in [1].

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2024 F. Asadi, Industrial Electronic Circuits Laboratory Manual, Synthesis Lectures on Electrical Engineering, https://doi.org/10.1007/978-3-031-50773-1_5

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Fig. 5.1 Boost converter circuit

5.3

Buck Converter

We used discrete components to make a Boost converter in the previous example. Many ICs were made to simplify making the DC-DC converters. You need to add few external components to these ICs to make the desired converter. In this experiment, we will use LM 2576 to make a Buck converter. Study the datasheet of this IC (This IC has 52 kHz switching frequency). Functional block diagram of this IC is shown in Sect. 7.2 of [2]. Let’s get started. Make the circuit shown in Fig. 5.2. Measure the output voltage and efficiency. Observe the waveform of diode D1 as well. Measure the frequency of observed waveform. See [3] to see another IC that can be used to make DC-DC converters.

Fig. 5.2 Buck converter circuit

5.5 Voltage-Inverting Converter with MC33063 IC

79

Fig. 5.3 Voltage inverting with TL7660 IC

5.4

Voltage-Inverting Converter with TL7660 IC

Sometimes you need a negative voltage to supply your circuit (i.e., circuits made with Op Amps) but you have only one power supply (for example you have only one 12 V batter). In these cases you can use TL7660 to convert a positive voltage into a negative voltage. Note that TL7660 provides a small output current for you. It is suitable for light loads only. Let’s get started. Make the circuit shown in Fig. 5.3 (input voltage is less than 3.5 V). Use a DC voltmeter to measure the average value of the output voltage. Connect different loads to the output (VOU T node) and use an oscilloscope to observe the load voltage. What happens to the load voltage waveform when the load current increases? Repeat the experiment with the circuit shown in Fig. 5.4.

5.5

Voltage-Inverting Converter with MC33063 IC

You can use a MC33063 IC for voltage polarity reversal as well. This IC provides more output current in comparison to TL7660. However, it requires more external components in comparison to TL7660. Let’s get started. Make the circuit shown in Fig. 5.5. Use a DC voltmeter to measure the average value of the output voltage. Connect different loads to the output (VOU T node) and use an oscilloscope to observe the load voltage. What happens to the load voltage waveform when the load current increases?

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5 DC-DC Converters

Fig. 5.4 Voltage inverting and doubling with TL7660 IC

Fig. 5.5 Voltage inverting with MC33063 IC

5.6

Voltage Inverting Converter with 555 IC

Previous experiments introduced two ways to generate a negative voltage from a given positive voltage. You can use the circuit shown in Fig. 5.6 as the third way of negative voltage generation. Let’s get started. Make the circuit shown in Fig. 5.6. Use a DC voltmeter to measure the average value of the output voltage. Connect different loads to the output (VOU T node) and use an oscilloscope to observe the load voltage. What happens to the load voltage waveform when the load current increases?

5.7 Voltage Doubler Circuit

81

Fig. 5.6 Voltage inverting with 555 IC

5.7

Voltage Doubler Circuit

The circuit shown in Fig. 5.7 can be used to boost the input DC voltage by factor of around 2. Note that this circuit can’t provide much output current for. It is suitable for low power applications only. The TL7660 IC can be used as voltage doubler as well [4]. Let’s get started. Make the circuit shown in Fig. 5.7. Use a DC voltmeter to measure the average value of the output voltage. Connect different loads to the output (VOU T node) and use an oscilloscope to observe the load voltage. What happens to the load voltage waveform when the load current increases?

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Fig. 5.7 Voltage doubler with 555 IC

References for Further Study 1. Asadi F., Eguchi K., Dynamics and Control of DC-DC Converters, Springer, 2018. DOI: https:// doi.org/10.1007/978-3-031-02502-0 2. https://bit.ly/45b3N2S 3. https://bit.ly/3E32LtP 4. https://bit.ly/45g6jVE 5. Mohan N., Undeland T., Robbins W., Power Electronics: Converters, Applications, and Design, Wiley, 2007. 6. Asadi F., Power Electronics Circuit Analysis with PSIM® , De Gruyter, 2021. DOI: https://doi. org/10.1515/9783110740653 7. Asadi F., Simulation of Power Electronics Circuits with MATLAB® /Simulink® : Design, Analyze, and Prototype Power Electronics, Apress, 2022. DOI: https://doi.org/10.1007/978-1-48428220-5 8. Asadi F., Eguchi K., Simulation of Power Electronics Converters Using PLECS® , Academic Press, 2019. DOI: https://doi.org/10.1016/C2018-0-02253-7 9. Asadi F., Analog Electronic Circuits Laboratory Manual, Springer, 2023. DOI: https://doi.org/ 10.1007/978-3-031-25122-1 10. Asadi F., Electric Circuits Laboratory Manual, Springer, 2023. DOI: https://doi.org/10.1007/ 978-3-031-24552-7 11. Asadi F., Essential Circuit Analysis using NI Multisim™ and MATLAB® , Springer, 2022. DOI: https://doi.org/10.1007/978-3-030-89850-2

References for Further Study

83

12. Asadi F., Essential Circuit Analysis Using Proteus® , Springer, 2022. DOI: https://doi.org/10. 1007/978-981-19-4353-9 13. Asadi F., Essential Circuit Analysis using LTspice® , Springer, 2022. DOI: https://doi.org/10. 1007/978-3-031-09853-6 14. Asadi F., Electric and Electronic Circuit Simulation using TINA-TI® , River Publishers, 2022. DOI: https://doi.org/10.13052/rp-9788770226851 15. Asadi F., Electric Circuit Analysis with EasyEDA, Springer, 2022. DOI: https://doi.org/10.1007/ 978-3-031-00292-2 16. Asadi F., Eguchi K., Electronic Measurement: A Practical Approach, Springer, 2021. DOI: https://doi.org/10.1007/978-3-031-02021-6

6

Filter and Comparator Circuits

6.1

Introduction

A comparator compares two voltages and indicate which is larger. A filter is a circuit that separate some frequencies from others. This chapter studies the important comparator and filter circuits.

6.2

Simple Comparator

1 The circuit shown in Fig. 6.1 compares the voltage V1 with 10+1 × 12V = 1.091 V. When V1 is bigger than 1.091 V, the output will be high. When V1 is less than 1.091 V, the output will be low. Make the circuit shown in Fig. 6.1 and observe the input and output waveforms. Does it work as expected? V1 is a sinusoidal signal with frequency of 1 kHz and peak value of 3 V. Change the circuit to what shown in Fig. 6.2 and observe the input and output waveforms. Compare the waveforms with previous experiment. What is the difference between this circuit and circuit shown in Fig. 6.1.

6.3

Window Comparator

A window comparator is a circuit that determines whether input signal is in a specific interval. Block diagram of window comparator is shown in Fig. 6.3.

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2024 F. Asadi, Industrial Electronic Circuits Laboratory Manual, Synthesis Lectures on Electrical Engineering, https://doi.org/10.1007/978-3-031-50773-1_6

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Fig. 6.1 Comparator circuit (input voltage is applied to positive terminal of the Op Amp)

Fig. 6.2 Comparator circuit (input voltage is applied to negative terminal of the Op Amp)

 The circuit shown in  Fig. 6.4 determines whether Vin is in the 1 2.2 = [1.092V, 2.164 V] interval. Output is high (LED 1+10 × 12V, 10+2.2 × 12 V is on) when input signal is in this interval.

6.3 Window Comparator

87

Fig. 6.3 Block diagram of a window comparator

Fig. 6.4 Window comparator for [1.092 V, 2.164 V] interval

Explain how circuit shown in Fig. 6.4 works. Then make the circuit and ensure that it works as expected. Apply 0 VDC, 1.5 VDC, 2.5 VDC and a sinusoidal signal with peak value of 3 V to the input and observe the output using an oscilloscope. Interpret the observed waveforms.

88

6.4

6 Filter and Comparator Circuits

Low Pass Filter

A simple passive low pass filter is shown in Fig. 6.5. Transfer function of this circuit is H (s) =

VC1 (s) Vin (s)

=

1 C1 s

R1 + C1 s 1

=

1 R1 C1 s+1

=

1 0.001s+1 .

Cut-off frequency of this filter is

= 159 Hz. Let’s use MATLAB to draw the frequency response of the circuit shown in Fig. 6.5. The code shown in Fig. 6.6 draws the frequency response for us. Output of this code is shown in Fig. 6.7. You can cascade two or more low pass filters in order to obtain a more accurate low pass filter. In Fig. 6.8 two low pass filters are cascaded. Transfer function of this filter is (s) 1 H (s) = VVout = R1 C11 s+1 × R2 C12 s+1 = (R C1 s+1)(R . 2 C 2 s+1) in (s) 1 Let’s use MATLAB to draw the frequency response of the circuit shown in Fig. 6.8. The code shown in Fig. 6.9 draws the frequency response for us. Output of this code is shown in Fig. 6.10. 1 2π R1 C1

Fig. 6.5 Low pass filter

Fig. 6.6 MATLAB code

6.4

Low Pass Filter

Fig. 6.7 Output of the MATLAB code

Fig. 6.8 Cascaded low pass filters

89

90

Fig. 6.9 MATLAB codes

Fig. 6.10 Output of MATLAB code

6 Filter and Comparator Circuits

6.4

Low Pass Filter

91

Fig. 6.11 MATLAB code

Fig. 6.12 Output of MATLAB code

Let’s draw Figs. 6.7 and 6.10 on the same graph. This helps us to compare them. The code shown in Fig. 6.11 draws both of the transfer functions on the same graph. Output of this code is shown in Fig. 6.12. Frequency response of circuits shown in Figs. 6.5 and 6.8 are shown with blue and red, respectively. Note that the red curve is steeper. Therefore, the circuit shown in Fig. 6.12 is a more accurate low pass filter.

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6 Filter and Comparator Circuits

Let’s get started. Make the circuit shown in Figs. 6.5 and 6.8. Apply a sinusoidal signal with amplitude of 1 V and measure the output amplitude for different frequencies. Use MATLAB (see Sect. A.7 in Appendix A) to draw the frequency response graph of obtained data.

6.5

High Pass Filter

A simple passive high pass filter is shown in Fig. 6.13. Transfer function of this circuit is V (s) 1s H (s) = VRin1(s) = R1 1 = R1RC1 C1 s+1 . Cut-off frequency of this filter is 2π R11 C1 . R1 + C

1s

You can cascade two or more low high filters in order to obtain a more accurate high pass filter. In Fig. 6.14 two high pass filters are cascaded. Transfer function of this filter 2 (s) 1s 2s 1 R2 C 1 C 2 s is H (s) = VVout = R1RC1 C1 s+1 × R2RC2 C2 s+1 = (R CR1 s+1)(R . 2 C 2 s+1) in (s) 1 The MATLAB code shown in Fig. 6.15 draws the frequency response of the circuits shown in Figs. 6.13 and 6.14 on the same graph. Output of this code is shown in Fig. 6.16. Frequency response of circuits shown in Figs. 6.13 and 6.14 are shown with blue and red, respectively. Note that the red curve is steeper. Therefore, the circuit shown in Fig. 6.14 is a more accurate high pass filter. Let’s get started. Make the circuit shown in Figs. 6.13 and 6.14. Apply a sinusoidal signal with amplitude of 1 V and measure the output amplitude for different frequencies.

Fig. 6.13 High pass filter

6.6

Band Pass Filter

93

Fig. 6.14 Cascaded high pass filters

Fig. 6.15 MATLAB code

Use MATLAB (see Sect. A.7 in Appendix A) to draw the frequency response graph of obtained data.

6.6

Band Pass Filter

Block diagram of a band pass filter is shown in Fig. 6.17. The circuit shown in Fig. 6.18 is a cascade connection of a high pass filter with cutoff frequency of 15.92 Hz and a low pass filter with cut-off frequency of 159.15 Hz. Frequencies in the [15.92 Hz, 159.15 Hz] pass through this filter. Transfer function of 1s × R2 C12 s+1 . circuit shown in Fig. 6.18 is H (s) = R1RC1 C1 s+1 The code shown in Fig. 6.19 draws the frequency response of the filter shown in Fig. 6.18. Output of this code is shown in Fig. 6.20.

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6 Filter and Comparator Circuits

Fig. 6.16 Output of MATLAB code

Fig. 6.17 Block diagram of a band pass filter

You can use the Op Amps to obtain the desired pass band gain as well (Fig. 6.21). Transfer function of the circuit shown in Fig. 6.22 is H (s) = (1 + RR43 ) × (1 + RR56 ) × R1 C 1 s R1 C1 s+1

× R2 C12 s+1 . Compare this transfer function with the transfer function of circuit shown in Fig. 6.18.

6.6

Band Pass Filter

95

Fig. 6.18 Band pass filter

Fig. 6.19 MATLAB code

The code shown in Fig. 6.23 draws the frequency response of the circuit shown in Fig. 6.22. Output of this code is shown in Fig. 6.24. Compare this graph with the one shown in Fig. 6.20. Let’s get started. Make the circuit shown in Figs. 6.18 and 6.22. Apply a sinusoidal signal with amplitude of 1 V and measure the output amplitude for different frequencies. Use MATLAB (see Sect. A.7 in Appendix A) to draw the frequency response graph of obtained data.

96

6 Filter and Comparator Circuits

Fig. 6.20 Output of MATLAB code

Fig. 6.21 Block diagram of a band pass filter with amplification

6.6

Band Pass Filter

Fig. 6.22 Band pass filter with amplification

Fig. 6.23 MATLAB code

97

98

6 Filter and Comparator Circuits

Fig. 6.24 Output of MATLAB code

References for Further Study 1. Asadi F., Power Electronics Circuit Analysis with PSIM® , De Gruyter, 2021. DOI: https://doi. org/10.1515/9783110740653 2. Asadi F., Simulation of Power Electronics Circuits with MATLAB® /Simulink® : Design, Analyze, and Prototype Power Electronics, Apress, 2022. DOI: https://doi.org/10.1007/978-1-48428220-5 3. Asadi F., Eguchi K., Simulation of Power Electronics Converters Using PLECS® , Academic Press, 2019. DOI: https://doi.org/10.1016/C2018-0-02253-7 4. Asadi F., Analog Electronic Circuits Laboratory Manual, Springer, 2023. DOI: https://doi.org/ 10.1007/978-3-031-25122-1 5. Asadi F., Electric Circuits Laboratory Manual, Springer, 2023. DOI: https://doi.org/10.1007/ 978-3-031-24552-7 6. Asadi F., Essential Circuit Analysis using NI Multisim™ and MATLAB® , Springer, 2022. DOI: https://doi.org/10.1007/978-3-030-89850-2

References for Further Study

99

7. Asadi F., Essential Circuit Analysis Using Proteus® , Springer, 2022. DOI: https://doi.org/10. 1007/978-981-19-4353-9 8. Asadi F., Essential Circuit Analysis using LTspice® , Springer, 2022. DOI: https://doi.org/10. 1007/978-3-031-09853-6 9. Asadi F., Electric and Electronic Circuit Simulation using TINA-TI® , River Publishers, 2022. DOI: https://doi.org/10.13052/rp-9788770226851 10. Asadi F., Electric Circuit Analysis with EasyEDA, Springer, 2022. DOI: https://doi.org/10.1007/ 978-3-031-00292-2 11. Asadi F., Eguchi K., Electronic Measurement: A Practical Approach, Springer, 2021. DOI: https://doi.org/10.1007/978-3-031-02021-6

7

Control of DC Motors

7.1

Introduction

A DC motor is an electrical motor that uses direct current to produce mechanical torque. Control of DC motors (i.e., control of shaft speed or position) is relatively easy. This makes the DC motors a good choice for many applications. This chapter shows how speed and direction of rotation of a permanent magnet brushed DC motor can be controlled.

7.2

Direction of Rotation Indicator

You can use the circuit shown in Fig. 7.1 to show the rotation direction of the motor. When motor rotates clockwise, one LED turns on and when the motor rotates counter clockwise, the other one turns on. Make the circuit shown in Fig. 7.1. Apply V1 = +12 V and V1 = −12 V and see the behaviour of the circuit.

7.3

DC Motor Speed Control

The circuit shown in Fig. 7.2 can be used to control the speed of a small DC motor. You can’t use this circuit to control the direction of rotation of motor. This circuit controls the speed of motor only. The PWM pulses (Fig. 7.3) turns on and turns off the MOSFET. In fact, the MOSFET control the average value of voltage applied to the armature and average value of armature voltage changes the motor speed. The diode is required to protect the MOSFET.

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2024 F. Asadi, Industrial Electronic Circuits Laboratory Manual, Synthesis Lectures on Electrical Engineering, https://doi.org/10.1007/978-3-031-50773-1_7

101

102

7 Control of DC Motors

Fig. 7.1 Direction of shaft rotation indicator

You can use a small sense resistor to measure the motor current (Fig. 7.4). Voltage across this sense resistor is proportional to the motor current. Sense resistor voltage is representative of motor current. Let’s get started. Make the circuit shown in Fig. 7.2 and apply a gate pulse with duty cycle of 20% and frequency of 500 Hz (Fig. 7.3). Increase the duty cycle from 20% up to 80% with 10% steps and observe the change of DC motor speed.

7.4

Control the Direction of Rotation

The circuit shown in Fig. 7.5 can be used to control the direction of rotation of the motor. This circuit can’t be used to control the speed of the motor. When the switch is in position A, transistor Q1 turns on and motor starts to rotate. Q2 is in cut-off mode in this case. When the switch is in position B, transistor Q2 turns on and motor starts to rotate in the reverse direction. Q1 is in cut-off mode in this case. Let’s get started. Make the circuit shown in Fig. 7.5. Put the switch in position A and B and see how the circuit behaves. Measure the voltages of the circuit and compare them with hand analysis results.

7.5

Full-Bridge Driver

103

Fig. 7.2 Speed control with MOSFET

Fig. 7.3 PWM signal

7.5

Full-Bridge Driver

L298 is a full bridge driver. You can use it to control the direction and speed of two separate DC motor. Operating supply voltage of L298 is up to 46 V and it can handle up to 4 A of current. L298 is used in closed-loop rotor position control systems as well.

104

7 Control of DC Motors

Fig. 7.4 Voltage of RSENSE is a representative of motor current

L298 pinout is shown in Fig. 7.6. The IN1 and IN2 pins control the direction of rotation for motor 1. Similarly, the IN3 and IN4 pins control the direction of rotation for motor 2. PWM signal for first motor is applied to ENA pin. PWM signal for second motor is applied to ENB pin. Armature of first motor is connected to OUT1 and OUT2 pins. Armature of second motor is connected to OUT3 and OUT4 pins. Motor power supply is connected to VC and GND pins. VCC is connected to +5 V. Let’s get started. Make the circuit shown in Fig. 7.7. Connect the ENA pin to a pulse with frequency of 500 Hz and duty cycle of 20% (Fig. 7.8). Increase the duty cycle from 20% up to 80% with 10% steps and observe the change of DC motor speed. RSENSE can be replaced with a short circuit. Voltage drop across RSENSE is representative of motor current (V Rsense = RS E N S E × Imotor ).

7.5

Full-Bridge Driver

Fig. 7.5 Control of direction of rotation Fig. 7.6 Pins of L298 IC

105

106

7 Control of DC Motors

Fig. 7.7 Test circuit for L298 IC

Fig. 7.8 PWM signal

Connect the IN1 and IN2 to GND and VCC, respectively (Fig. 7.9) and repeat the experiment. Note that this time direction of rotation of the motor is the reverse of previous case. Connect both of IN1 and IN2 to ground (Fig. 7.10) and repeat the experiment. What happens?

7.6

Speed Control of Universal Motors

The universal motor is a type of electric motors that can operate on either AC or DC power. A dimmer (Fig. 7.11) can be used to control the speed of universal motors. Simulate the circuit shown in Fig. 7.11 and observe the waveform of different nodes. You can use a 484 Ω resistor as load. Don’t try to make this circuit on breadboard. Realization of this circuit requires a printed circuit board and it must be tested under the supervision of lab instructor.

7.7

Stepper Motor and BLDC Motor Driver

107

Fig. 7.9 IN1 and IN2 are 0 and +5 V, respectively

Fig. 7.10 Both of IN1 and IN2 are 0 V

7.7

Stepper Motor and BLDC Motor Driver

Stepper and BLDC motors can be controlled quite easy with the aid of cheap ready to use drivers. Refer to Chap. 8 of [1] for more information.

108

7 Control of DC Motors

Fig. 7.11 A dimer circuit can be used to control the speed of a DC motors

References for Further Study 1. Asadi F., Essential of Arduino Boards Programming: Step-by-Step Guide to Master Arduino Boards Hardware and Software, Apress, 2023, DOI: https://doi.org/10.1007/978-1-4842-9600-4 2. Mohan N., Advanced Electric Drives: Analysis, Control, and Modeling Using MATLAB / Simulink, Wiley, 2008. 3. Asadi F., Power Electronics Circuit Analysis with PSIM® , De Gruyter, 2021. DOI: https://doi. org/10.1515/9783110740653 4. Asadi F., Simulation of Power Electronics Circuits with MATLAB® /Simulink® : Design, Analyze, and Prototype Power Electronics, Apress, 2022. DOI: https://doi.org/10.1007/978-1-48428220-5 5. Asadi F., Eguchi K., Simulation of Power Electronics Converters Using PLECS® , Academic Press, 2019. DOI: https://doi.org/10.1016/C2018-0-02253-7 6. Asadi F., Analog Electronic Circuits Laboratory Manual, Springer, 2023. DOI: https://doi.org/ 10.1007/978-3-031-25122-1 7. Asadi F., Electric Circuits Laboratory Manual, Springer, 2023. DOI: https://doi.org/10.1007/ 978-3-031-24552-7 8. Asadi F., Essential Circuit Analysis using NI Multisim™ and MATLAB® , Springer, 2022. DOI: https://doi.org/10.1007/978-3-030-89850-2 9. Asadi F., Essential Circuit Analysis Using Proteus® , Springer, 2022. DOI: https://doi.org/10. 1007/978-981-19-4353-9 10. Asadi F., Essential Circuit Analysis using LTspice® , Springer, 2022. DOI: https://doi.org/10. 1007/978-3-031-09853-6 11. Asadi F., Electric and Electronic Circuit Simulation using TINA-TI® , River Publishers, 2022. DOI: https://doi.org/10.13052/rp-9788770226851 12. Asadi F., Electric Circuit Analysis with EasyEDA, Springer, 2022. DOI: https://doi.org/10.1007/ 978-3-031-00292-2

References for Further Study

109

13. Asadi F., Eguchi K., Electronic Measurement: A Practical Approach, Springer, 2021. DOI: https://doi.org/10.1007/978-3-031-02021-6 14. https://bit.ly/3qESDo6 15. https://bit.ly/3KIANre

8

Delay Circuits

8.1

Introduction

Sometimes you need to turn on/off a load with a certain delay after a specific event. For instance, consider the staircase corridor lighting system: when you press the key, the lights are turned on for a specific time (typically 2–3 min.). Then they turn off automatically. This chapter shows how different types of delay circuits can be made.

8.2

Delay Circuit with Transistor (Normally on Circuit)

The LED is on in Fig. 8.1. When you press the push button, the LED turns off for a while and it turns on again after a delay. Amount of delay is determined by the capacitor C1 and Thevenin resistance seen from its terminals. The potentiometer affects the Thevenin resistance seen from the capacitor. Therefore, we can say that amount of delay is determined by the potentiometer. Make the circuit shown in Fig. 8.1. Measure the minimum and maximum delays that you can generate with this circuit. Replace the 1000 µF capacitor with a 2200 µF capacitor and repeat the experiment. What is the relationship between the results of two experiments? Use hand analysis to obtain a formula for the amount of delay. Explain how this circuit works.

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2024 F. Asadi, Industrial Electronic Circuits Laboratory Manual, Synthesis Lectures on Electrical Engineering, https://doi.org/10.1007/978-3-031-50773-1_8

111

112

8 Delay Circuits

Fig. 8.1 Delay circuit with BJT (by default the transistor is on)

8.3

Delay Circuit with Transistor (Normally Off Circuit)

The LED is off in Fig. 8.2. When you press the push button, the LED turns on for a while and it turns off again after a delay. Amount of delay is determined by the capacitor C1 and Thevenin resistance seen from its terminals. The potentiometer affects the Thevenin resistance seen from the capacitor. Therefore, we can say that amount of delay is determined by the potentiometer. Make the circuit shown in Fig. 8.2. Measure the minimum and maximum delays that you can generate with this circuit. Replace the 1000 µF capacitor with a 2200 µF capacitor and repeat the experiment. What is the relationship between the results of two experiments? Explain how this circuit works.

8.4

Delay Circuit with 555 IC

113

Fig. 8.2 Delay circuit with BJT (by default the output transistor Q2 is off)

8.4

Delay Circuit with 555 IC

The mono-stable circuit shown in Fig. 8.3 can be used to generate delay. The output by default is at low level (i.e., 0 V). When you press the push button, the output becomes high (i.e., VCC) for duration of t = 1.1 × R2 × C1 . After t = 1.1 × R2 × C1 , the output returns to low level. Make the circuit shown in Fig. 8.3. Press the push button and measure the amount of delay that you observe after releasing the push button. Use an oscilloscope to observe the waveforms of the circuit.

114

8 Delay Circuits

Fig. 8.3 Monostable circuit with 555 IC

Output of 555 can stimulate a relay. In Fig. 8.4 the red LED is on by default. When you press the push button the green led turns on for duration of t = 1.1 × R2 × C1 . After t = 1.1 × R2 × C1 the red led turns on again. Make the circuit shown in Fig. 8.4 and ensure that it works as expected.

8.5

555 Timer IC Based Circuit Design

NI® Multisim™ software can be used to design the 555 based circuits. The tool can be accessed in the Tools menu (Fig. 8.5). You can use this tool to design Astable (Fig. 8.6) or Mono stable (Fig. 8.7) circuits.

8.5

555 Timer IC Based Circuit Design

Fig. 8.4 Output of 555 IC can stimulate a relay Fig. 8.5 Tools > circuit wizards > 555 timer wizard

115

116

Fig. 8.6 Astable circuit design

Fig. 8.7 Monostable circuit design

8 Delay Circuits

References for Further Study

117

References for Further Study 1. Bell D., Solid State Pulse Circuits, Prentice Hall, 2008. 2. Asadi F., Power Electronics Circuit Analysis with PSIM® , De Gruyter, 2021. DOI: https://doi. org/10.1515/9783110740653 3. Asadi F., Simulation of Power Electronics Circuits with MATLAB® /Simulink® : Design, Analyze, and Prototype Power Electronics, Apress, 2022. DOI: https://doi.org/10.1007/978-1-48428220-5 4. Asadi F., Eguchi K., Simulation of Power Electronics Converters Using PLECS® , Academic Press, 2019. DOI: https://doi.org/10.1016/C2018-0-02253-7 5. Asadi F., Analog Electronic Circuits Laboratory Manual, Springer, 2023. DOI: https://doi.org/ 10.1007/978-3-031-25122-1 6. Asadi F., Electric Circuits Laboratory Manual, Springer, 2023. DOI: https://doi.org/10.1007/ 978-3-031-24552-7 7. Asadi F., Essential Circuit Analysis using NI Multisim™ and MATLAB® , Springer, 2022. DOI: https://doi.org/10.1007/978-3-030-89850-2 8. Asadi F., Essential Circuit Analysis Using Proteus® , Springer, 2022. DOI: https://doi.org/10. 1007/978-981-19-4353-9 9. Asadi F., Essential Circuit Analysis using LTspice® , Springer, 2022. DOI: https://doi.org/10. 1007/978-3-031-09853-6 10. Asadi F., Electric and Electronic Circuit Simulation using TINA-TI® , River Publishers, 2022. DOI: https://doi.org/10.13052/rp-9788770226851 11. Asadi F., Electric Circuit Analysis with EasyEDA, Springer, 2022. DOI: https://doi.org/10.1007/ 978-3-031-00292-2 12. Asadi F., Eguchi K., Electronic Measurement: A Practical Approach, Springer, 2021. DOI: https://doi.org/10.1007/978-3-031-02021-6

Drawing Graphs with MATLAB®

A.1

Introduction

This appendix shows how to draw different types of graphs with MATLAB.

A.2

fplot Command

Assume that you want to draw the graph of sin(x) for [0, 2π ] interval. The commands shown in Fig. A.1 do this job for you. Output of this code is shown in Fig. A.2. You click on any point in order to read its coordinate (Fig. A.3).

A.3

Plotting the Graph of a Numeric Data

In the previous section you learned how to draw the graph of a symbolic function. In this section we learn how to draw the graph of a numeric data. Plotting the graph of a numeric data is very simple in MATLAB. You need to use the plot command. Let’s make a numeric data (Fig. A.4).

Fig. A.1 fplot command can be used to draw symbolic expressions

© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2024 F. Asadi, Industrial Electronic Circuits Laboratory Manual, Synthesis Lectures on Electrical Engineering, https://doi.org/10.1007/978-3-031-50773-1

119

120

Drawing Graphs with MATLAB®

Fig. A.2 Output of code in Fig. A.1

The plot command shown in Fig. A.5 draws the graph of the numeric data. Output of this code is shown in Fig. A.6. You can add the operators shown in Tables A.1, A.2 and A.3 to produce more custom plots. Let’s study an example. Values of voltage and current for a resistor is shown in Table A.4. We want to plot the graph of this data. We want to show the data points with circles and connect them together using dashed line with black color. The vertical axis and horizontal axis must have the labels “Current (A)” and “Voltage (V)”, respectively. The title of the graph must be “I-V for a resistor”. The commands shown in Fig. A.7 do what we need. The result is shown in Fig. A.8.

Drawing Graphs with MATLAB®

121

Fig. A.3 Reading the points on the graph Fig. A.4 Making a simple sample data

The commands shown in Fig. A.9 draw the I-V graph of Table A.4. However, it uses red star for data points and solid black color for connecting the data points together (Fig. A.10).

122

Drawing Graphs with MATLAB®

Fig. A.5 Drawing the graph of a numeric data with plot command

Fig. A.6 Output of code in Fig. A.5

Drawing Graphs with MATLAB® Table A.1 Types of lines

Table A.2 Colors

Table A.3 Plot symbols

A.4

123

MATLAB command

Type of line

-

Solid

:

Dotted

-.

Dashdot

--

Dashed

MATLAB command

Color

r

Red

g

Green

b

Blue

c

Cyan

m

Magenta

y

Yellow

k

Black

w

White

MATLAB command

Plot symbol

.

Point

+

Plus

*

Star

O

Circle

x

x-mark

s

Square

d

Diamond

v

Triangle (down)

^

Triangle (up)




Triangle (right)

Addition of Labels and Title to the Drawn Graph

Figure A.10 doesn’t have any labels and title. You can add the desired labels and titles to it with the aid of insert menu (Fig. A.11)

Drawing Graphs with MATLAB®

124 Table A.4 V-I values for resistor R1

V (volt)

I (Amper)

0.499

0.10

0.985

0.20

1.508

0.31

1.969

0.41

2.528

0.53

2.935

0.61

3.481

0.73

3.971

0.83

4.486

0.94

4.960

1.04

5.502

1.15

6.007

1.26

6.60

1.38

Fig. A.7 Drawing the graph of data in Table A.4

A.5

Exporting the Drawn Graph as a Graphical File

You can copy the drawn graph to the clipboard easily with the aid of Edit > Copy Figure (Fig. A.12). After copying the graph to the clipboard you can easily paste it in programs like MS Word® by pressing Ctrl + V. You can save the drawn graph as a graphical file as well. To do this, click use the File > Save As (Fig. A.13). After clicking, the save as window appears. Select the desired output format from the Save as type drop down list (Fig. A.14).

Drawing Graphs with MATLAB®

125

Fig. A.8 Output of code in Fig. A.7

Fig. A.9 Drawing the graph of data in Table A.4

A.6

Drawing Two or More Graphs on the Same Axis

Sometimes you need to show two or more datasets on the same graph. You need to use the hold on command to show two or more graphs simultaneously. Assume that we have another dataset (Table A.5) and we want to show both datasets (Tables A.4 and A.5) on the same graph.

126

Drawing Graphs with MATLAB®

Fig. A.10 Output of code in Fig. A.9

The commands shown in Fig. A.15 draws the graph of both datasets on the same graph. Output of this code is shown in Fig. A.16. You can use the Insert > Legend to show which graph belongs to which resistor (Fig. A.17). After clicking the Insert > Legend, the legend shown in Fig. A.18 will be added to the graph. Double click the data1 in the legend box (Fig. A.18) and enter the desired text. Repeat this for data2, data3 and data4 in Fig. A.18. You can move the legend box by clicking on it, holding down the mouse button and dragging it to the desired location (Fig. A.19). You can even right click on the legend box and use the predefined locations (Fig. A.20).

Drawing Graphs with MATLAB®

127

Fig. A.11 Addition of title and labels to the axis

A.7

Logarithmic Axis

We used linear axis in order to draw the I-V graph of studied resistors. If you want to draw the frequency response graphs you need to use logarithmic axis. The linear axis is not a suitable option for frequency response graphs. Let’s study an example. Assume the frequency response given in Table A.6. This table shows the frequency response of the circuit shown in Fig. A.21. The commands shown in Fig. A.22, draws the frequency response of the data in Table A.6. The command semilogx is used to draw the frequency response graph. Output of this code is shown in Fig. A.23.

128

Fig. A.12 Copying the drawn figure to the clipboard memory

Drawing Graphs with MATLAB®

Drawing Graphs with MATLAB®

Fig. A.13 Saving the graph as a graphical file

Fig. A.14 Selection of desired type of file

129

Drawing Graphs with MATLAB®

130 Table A.5 V-I values for resistor R2

V (volt)

I (Amper)

0.579

0.10

0.978

0.17

1.598

0.28

1.976

0.34

2.496

0.43

2.953

0.51

3.458

0.60

4.068

0.71

4.450

0.78

4.917

0.86

5.35

0.93

5.75

1.01

6.37

1.11

6.60

1.15

Fig. A.15 Drawing the graph of Tables A.4 and A.5 on the same graph

Drawing Graphs with MATLAB®

Fig. A.16 Output of code in Fig. A.15

131

132

Drawing Graphs with MATLAB®

Fig. A.17 Insert > Legend can be used to add a legend to the graph

Drawing Graphs with MATLAB®

Fig. A.18 Legend is added to the graph

133

134

Fig. A.19 Customized legend

Drawing Graphs with MATLAB®

Drawing Graphs with MATLAB®

135

Fig. A.20 Default locations for legend

Table A.6 Frequency response of a RC circuit

      V ( j ω) Frequency (Hz) Magnitude  VV o (( jjω)  Phase  V ion ( j ω) i n ω) 1

1.000

−0.36°

10

0.998

−3.60°

20

0.992

−7.16°

50

0.954

−17.44°

100

0.847

−32.13°

150

0.728

−43.30°

200

0.623

−51.48°

250

0.537

−57.51°

300

0.469

−62.05°

350

0.414

−65.54°

400

0.370

−68.30°

450

0.333

−70.51°

500

0.303

−72.34°

550

0.278

−73.85°

600

0.256

−75.14°

136

Fig. A.21 Simple RC circuit

Fig. A.22 Drawing the graph of data in Table A.6

Drawing Graphs with MATLAB®

Drawing Graphs with MATLAB®

Fig. A.23 Output of code in Fig. A.22

137

138

Drawing Graphs with MATLAB®

Reference for Further Study 1. Asadi F., Applied Numerical Analysis with MATLAB® /Simulink® , Springer, 2022. DOI: https://doi. org/10.1007/978-3-031-19366-8