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Introduction to Electric Circuits To the memory of my mother and father with grateful thanks Essential Electronics Series Introduction to Electric Circuits Eur Ing R G Poweli Principal Lecturer Department of Electrical and Electronic Engineering Nottingham Trent University ARNOLD A m e m b e r of tile H o d d e r Headline G r o u p LONDON 9 S Y D N E Y 9A U C K L A N D First published in Great Britain 1995 by Arnold, a member of the Hodder Headline Group, 338 Euston Road, London NWl 3BH 9 1995 Ray Powell All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronically or mechanically, including photocopying, recording or any information storage or retrieval system, without either prior permission in writing from the publisher or a licence permitting restricted copying. In the United Kingdom such licences are issued by the Copyright Licensing Agency: of 90 Tottenham Court Road, London WlP 9HE. Whilst the advice and information in this book is believed to be true and accurate at the date of going to press, neither the author[s] nor the publisher can accept any legal responsibility or liability for any errors or omissions that may be made. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging-in-Publication Data A catalog record for this book is available from the Library of Congress ISBN 0340 63198 8 2345 Typeset in 10~/13 89Times by Wearset, Boldon, Tyne and Wear. Printed and bound in Great Britain by J W Arrowsmith Ltd, Bristol. Series Preface In recent years there have been many changes in the structure of undergraduate courses in engineering and the process is continuing. With the advent of modularization, semesterization and the move towards student-centred learning as class contact time is reduced, students and teachers alike are having to adjust to new methods of learning and teaching. Essential Electronics is a series of textbooks intended for use by students on degree and diploma level courses in electrical and electronic engineering and related courses such as manufacturing, mechanical, civil and general engineering. Each text is complete in itself and is complementary to other books in the series. A feature of these books is the acknowledgement of the new culture outlined above and of the fact that students entering higher education are now, through no fault of their own, less well equipped in mathematics and physics than students of ten or even five years ago. With numerous worked examples throughout, and further problems with answers at the end of each chapter, the texts are ideal for directed and independent learning. The early books in the series cover topics normally found in the first and second year curricula and assume virtually no previous knowledge, with mathematics being kept to a minimum. Later ones are intended for study at final year level. The authors are all highly qualified chartered engineers with wide experience in higher education and in industry. R G Powell Jan 1995 Nottingham Trent University This Page Intentionally Left Blank Contents Preface Acknowledgements xi xiii 1.1 1.2 1.3 1.4 1.5 1.6 Chapter 1 Units and dimensions Introduction The Syst~me International d'Unit~s Dimensional analysis Multiples and submultiples of units Self-assessment test Problems 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 Chapter 2 Electric circuit elements Electricity Electric circuits Circuit elements Lumped parameters Energy stored in circuit elements Power dissipated in circuit elements Self-assessment test Problems 10 11 11 34 35 36 37 38 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 Chapter 3 DC circuit analysis Introd