Electronic Circuits

441 Pages·2006·21.51 MB·English

by  Michael Tooley

Electronic Circuits: Fundamentals and
Applications
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Electronic Circuits: Fundamentals and
Applications
Third Edition

Michael Tooley BA

Formerly Vice Principal
Brooklands College of Further and Higher Education
Newnes is an imprint of Elsevier
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First published 2006

Copyright © 2006, Mike Tooley. Published by Elsevier Ltd. All rights reserved

The right of Mike Tooley to be identified as the author of this work has been asserted in accordance with the
Copyright, Designs and Patents Act 1988

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Notice
No responsibility is assumed by the publisher for any injury and/or damage to persons or property as a matter of
products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions
or ideas contained in the material herein. Because of rapid advances in the medical sciences, in particular,
independent verification of diagnoses and drug dosages should be made

British Library Cataloguing in Publication Data
Acatalogue record for this book is available from the British Library

Library of Congress Cataloging-in-Publication Data
Acatalog record for this book is available from the Library of Congress

ISBN-13: 978-0-75-066923-8
ISBN-10: 0-75-066923-3
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Typeset by the author
Printed and bound in Great Britain
Contents
Preface vii 15 Fault finding 273
Aword about safety ix 16 Sensors and interfacing 287
1 Electrical fundamentals 1 17 Circuit simulation 303
2 Passive components 21 18 The PIC microcontroller 313
3 D.C. circuits 49 19 Circuit construction 327
4 Alternating voltage and current 69 Appendix 1 Student assignments 361
5 Semiconductors 87 Appendix 2 Revision problems 364
6 Power supplies 115 Appendix 3 Answers to problems 374
7 Amplifiers 131 Appendix 4 Pin connections 377
8 Operational amplifiers 157 Appendix 5 1N4148 data sheet 379
9 Oscillators 171 Appendix 6 2N3904 data sheet 382
10 Logic circuits 183 Appendix 7 Decibels 388
11 Microprocessers 199 Appendix 8 Mathematics for electronics 390
12 The 555 timer 217 Appendix 9 Useful web addresses 415
13 Radio 227 Index 417
14 Test equipment and measurements 245
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Preface
This is the book that I wish I had when I first also to give you some experience of the ‘short
started exploring electronics nearly half a century answer’ questions used in most in-course
ago. In those days, transistors were only just assessments. For good measure, we have included
making their debut and integrated circuits were 70 revision problems in Appendix 2. At the end of
completely unknown. Of course, since then much the book you will find 21 sample coursework
has changed but, despite all of the changes, the assignments. These should give you plenty of ‘food
world of electronics remains a fascinating one. for thought’ as well as offering you some scope for
And, unlike most other advanced technological further experimentation. It is not envisaged that you
disciplines, electronics is still something that you should complete all of these assignments and a
can ‘do’ at home with limited resources and with a carefully chosen selection will normally suffice. If
minimal outlay. A soldering iron, a multi-meter, you are following a formal course, your teacher or
and a handful of components are all that you need lecturer will explain how these should be tackled
to get started. Except, of course, for some ideas to and how they can contribute to your course
get you started—and that’s exactly where this book assessment. While the book assumes no previous
comes in! knowledge of electronics you need to be able to
The book has been designed to help you manipulate basic formulae and understand some
understand how electronic circuits work. It will simple trigonometry in order to follow the
provide you with the basic underpinning numerical examples. A study of mathematics to
knowledge necessary to appreciate the operation of GCSE level (or equivalent) will normally be
a wide range of electronic circuits including adequate to satisfy this requirement. However, for
amplifiers, logic circuits, power supplies and those who may need a refresher or have had
oscillators. previous problems with mathematics, Appendix 6
The book is ideal for people who are studying will provide you with the underpinning
electronics for the first time at any level including a mathematical knowledge required.
wide range of school and college courses. It is In the later chapters of the book, a number of
equally well suited to those who may be returning representative circuits (with component values)
to study or who may be studying independently as have been included together with sufficient
well as those who may need a quick refresher. The information to allow you to adapt and modify the
book has 19 chapters, each dealing with a particular circuits for your own use. These circuits can be
topic, and eight appendices containing useful used to form the basis of your own practical
information. The approach is topic-based rather investigations or they can be combined together in
than syllabus-based and each major topic looks at a more complex circuits.
particular application of electronics. The relevant Finally, you can learn a great deal from building,
theory is introduced on a progressive basis and testing and modifying simple circuits. To do this
delivered in manageable chunks. you will need access to a few basic tools and some
In order to give you an appreciation of the minimal test equipment. Your first purchase should
solution of simple numerical problems related to be a simple multi-range meter, either digital or
the operation of basic circuits, worked examples analogue. This instrument will allow you to
have been liberally included within the text. In measure the voltages and currents present so that
addition, a number of problems can be found at the you can compare them with the predicted values. If
end of each chapter and solutions are provided at you are attending a formal course of instruction and
the end of the book. You can use these end-of- have access to an electronics laboratory, do make
chapter problems to check your understanding and full use of it!
viii PREFACE
24 weeks) to deliver in which the total of 90 hours
Anote for teachers and lecturers of study time should be divided equally into theory
(supported by problem solving) and practical
(laboratory and assignment work). The
The book is ideal for students following formal
recommended four or five assignments will require
courses (e.g. GCSE, AS, A-level, BTEC, City and
about 25 to 30 hours of student work to complete.
Guilds, etc.) in schools, sixth-form colleges, and
Finally, when constructing a teaching programme it
further/higher education colleges. It is equally well
is, of course, essential to check that you fully
suited for use as a text that can support distance or
comply with the requirements of the awarding body
flexible learning and for those who may need a
concerning assessment and that the syllabus
‘refresher’ before studying electronics at a higher
coverage is adequate.
level.

While the book assumes little previous
knowledge students need to be able to manipulate
Mike Tooley
basic formulae and understand some simple
January 2006
trigonometry to follow the numerical examples. A
study of mathematics to GCSE level (or beyond)
will normally be adequate to satisfy this
requirement.
However, an appendix has been added
specifically to support students who may have
difficulty with mathematics. Students will require a
scientific calculator in order to tackle the end-of-
chapter problems as well as the revision problems
that appear at the end of the book.
We have also included 21 sample coursework
assignments. These are open-ended and can be
modified or extended to suit the requirements of the
particular awarding body. The assignments have
been divided into those that are broadly at Level 2
and those that are at Level 3. In order to give
reasonable coverage of the subject, students should
normally be expected to complete between four and
five of these assignments. Teachers can
differentiate students’ work by mixing assignments
from the two levels. In order to challenge students,
minimal information should be given to students at
the start of each assignment. The aim should be that
of giving students ‘food for thought’ and
encouraging them to develop their own solutions
and interpretation of the topic.
Where this text is to be used to support formal
teaching it is suggested that the chapters should be
followed broadly in the order that they appear with
the notable exception of Chapter 14. Topics from
this chapter should be introduced at an early stage
in order to support formal lab work. Assuming a
notional delivery time of 4.5 hours per week, the
material contained in this book (together with
supporting laboratory exercises and assignments)
will require approximately two academic terms (i.e.
A word about safety
When working on electronic circuits, personal The severity of electric shock depends upon several
safety (both yours and of those around you) should factors including the magnitude of the current,
be paramount in everything that you do. Hazards whether it is alternating or direct current, and its
can exist within many circuits—even those that, on precise path through the body. The magnitude of
the face of it, may appear to be totally safe. the current depends upon the voltage which is
Inadvertent misconnection of a supply, incorrect applied and the resistance of the body. The
earthing, reverse connection of a high-value electrical energy developed in the body will depend
electrolytic capacitor, and incorrect component upon the time for which the current flows. The
substitution can all result in serious hazards to duration of contact is also crucial in determining
personal safety as a consequence of fire, explosion the eventual physiological effects of the shock. As
or the generation of toxic fumes. a rough guide, and assuming that the voltage
Potential hazards can be easily recognized and it applied is from the 250 V 50 Hz a.c. mains supply,
is well worth making yourself familiar with them the following effects are typical:
but perhaps the most important point to make is
that electricity acts very quickly and you should
always think carefully before working on circuits Current Physiological effect
where mains or high voltages (i.e. those over 50 V,
less than 1 mA Not usually noticeable
or so) are present. Failure to observe this simple
precaution can result in the very real risk of electric 1mA to 2 mA Threshold of perception
shock.
(a slight tingle may be felt)
Voltages in many items of electronic equipment,
2mA to 4 mA Mild shock (effects of current
including all items which derive their power from
flow are felt)
the a.c. mains supply, are at a level which can cause
sufficient current flow in the body to disrupt 4mA to 10 mA Serious shock (shock is felt
normal operation of the heart. The threshold will be as pain)
even lower for anyone with a defective heart.
10 mA to 20 mA Motor nerve paralysis may
Bodily contact with mains or high-voltage circuits
occur (unable to let go)
can thus be lethal. The most critical path for
electric current within the body (i.e. the one that is
20 mA to 50 mA Respiratory control inhibited
most likely to stop the heart) is that which exists
(breathing may stop)
from one hand to the other. The hand-to-foot path
is also dangerous but somewhat less dangerous than more than 50 mA Ventricular fibrillation of
the hand-to-hand path. heart muscle (heart failure)
So, before you start to work on an item of
electronic equipment, it is essential not only to
It is important to note that the figures are quoted as
switch off but to disconnect the equipment at the
a guide—there have been cases of lethal shocks
mains by removing the mains plug. If you have to
resulting from contact with much lower voltages
make measurements or carry out adjustments on a
and at relatively small values of current. The upshot
piece of working (or ‘live’) equipment, a useful
of all this is simply that any potential in excess of
precaution is that of using one hand only to perform
50 V should be considered dangerous. Lesser
the adjustment or to make the measurement. Your
potentials may, under unusual circumstances, also
‘spare’ hand should be placed safely away from
be dangerous. As such, it is wise to get into the
contact with anything metal (including the chassis
habit of treating all electrical and electronic
of the equipment which may, or may not, be
circuits with great care.
earthed).