Fundamental Electrical and Electronic Principles

1 Fundamental Electrical and Electronic Principles This page intentionally left blank Fundamental Electrical and Electronic Principles Third Edition Christopher R Robertson AMSTERDAM BOSTON HEIDELBERG LONDON NEW YORK OXFORD. PARIS SAN DIEGO SAN FRANCISCO SINGAPORE SYDNEY TOKYO. Newnes is an imprint of Elsevier Newnes is an imprint of Elsevier Linacre House, Jordan Hill, Oxford OX2 8DP, UK. 30 Corporate Drive, Suite 400, Burlington, MA 01803, USA. First published 1993 as Electrical and Electronic Principles 1 by Edward Arnold Second edition 2001.

2 Third edition 2008. Copyright C. R. Robertson 1993, 2001. Copyright 2008 Elsevier Ltd. All rights reserved The right of Christopher R. Robertson to be identi ed as the author of this work has been asserted in accordance with the Copyright, Designs and Patents Act 1988. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means Electronic , mechanical, photocopying, recording or otherwise without the prior written permission of the publisher Permissions may be sought directly from Elsevier's Science & Technology Rights Department in Oxford, UK: phone ( 44) (0) 1865 843830; fax ( 44) (0).

3 1865 853333; email: Alternatively you can submit your request online by visiting the Elsevier web site at permissions, and selecting Obtaining permission to use Elsevier material 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. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloguing in Publication Data A catalogue record for this book is available from the Library of Congress ISBN: 978-0-7506-8737-9.

4 For information on all Newnes publications visit our web site at Typeset by Charon Tec Ltd., A Macmillan Company. ( ). Printed and bound in Slovenia 08 09 10 11 12 10 9 8 7 6 5 4 3 2 1. Contents 1 Units ..1. Standard Form Scientific' Notation ..2. Conversion of Areas and Basic Electrical Concepts ..7. Summary of Equations ..29. Assignment Questions ..30. 2 Circuits .. 31. Resistors in Series ..31. Resistors in Parallel ..35. Potential Divider ..40. Current Divider ..41. Series/Parallel Combinations ..43. Kirchhoff 's Current Law.

5 48. Kirchhoff 's Voltage Law ..49. The Wheatstone Bridge Network ..55. The Wheatstone Bridge Instrument ..63. The Slidewire Potentiometer ..65. Summary of Equations ..68. Assignment Questions ..69. Suggested Practical Assignments ..72. 3 Electric Fields and Capacitors .. 75. Coulomb's Law ..75. Electric Fields ..76. Electric Field Strength (E) ..78. Electric Flux ( ) and Flux Density (D) ..79. The Charging Process and Potential Gradient ..80. Capacitance (C) ..83. Capacitors ..84. Permittivity of Free Space ( 0).

6 84. Relative Permittivity ( r)..84. Absolute Permittivity ( ) ..85. v vi Contents Calculating Capacitor Capacitors in Parallel ..87. Capacitors in Series ..89. Series/Parallel Combinations ..92. Multiplate Capacitors ..95. Energy Stored ..97. Dielectric Strength and Working Voltage ..101. Capacitor Types ..102. Summary of Equations ..105. Assignment Questions ..107. Suggested Practical Assignment ..110. 4 Magnetic Fields and Magnetic Magnetic Fields ..111. The Magnetic Circuit ..114. Magnetic Flux and Flux Magnetomotive Force (mmf ).

7 116. Magnetic Field Strength ..117. Permeability of Free Space ( 0) ..118. Relative Permeability ( r)..119. Absolute Permeability ( ) ..119. Magnetisation (B/H) Curve ..122. Composite Series Magnetic Circuits ..126. Reluctance (S) ..128. Comparison of Electrical , Magnetic and Electrostatic Quantities ..131. Magnetic Hysteresis ..132. Parallel Magnetic Circuits ..134. Summary of Equations ..135. Assignment Questions ..136. Suggested Practical Assignments ..138. 5 Electromagnetism .. 141. Faraday 's Law of Electromagnetic Lenz 's Fleming's Righthand Rule.

8 144. EMF Induced in a Single Straight Conductor ..147. Force on a Current-Carrying The Motor Principle ..153. Force between Parallel Conductors ..156. The Moving Coil Meter ..158. Shunts and Multipliers ..162. Shunts ..162. Multipliers ..163. Contents vii Figure of Merit and Loading Effect ..166. The Ohmmeter ..170. Wattmeter ..171. Eddy Currents ..172. Self and Mutual Inductance ..174. Self-Inductance ..175. Self-Inductance and Flux Linkages ..176. Factors Affecting Inductance ..179. Mutual Relationship between Self- and Energy Stored.

9 184. The Transformer Principle ..186. Transformer Voltage and Current Ratios ..188. Summary of Equations ..191. Assignment Questions ..192. Suggested Practical Assignments ..195. 6 Alternating Quantities .. 197. Production of an Alternating Waveform ..197. Angular Velocity and Frequency ..200. Standard Expression for an Alternating Quantity ..200. Average Value ..205. Peak Factor ..206. Form Rectifiers ..208. Half-wave Rectifier ..209. Full-wave Bridge Rectifier ..210. Rectifier Moving Coil Meter ..212. Phase and Phase Angle.

10 213. Phasor Addition of Alternating The Cathode Ray Oscilloscope ..224. Operation of the Oscilloscope ..226. Dual Beam Oscilloscopes ..228. Summary of Equations ..229. Assignment Questions ..230. Suggested Practical Assignments ..232. 7 Machines .. 233. Motor/Generator Duality ..233. The Generation of Construction of Machines .. 238. Classification of Generators ..238. viii Contents Separately Excited Generator ..239. Shunt Generator ..240. Series Generator ..242. D. C. Motors ..244. Shunt Motor ..244. Series Motor.