www.EngineeringEbooksPdf.com Electrical Circuit Theory and Technology A fully comprehensive text for courses in electrical principles, circuit theory and electrical technology, providing 800 worked examples and over 1,350 further problems for students to work through at their own pace This book is ideal for students studying engineering for the first time as part of BTEC National and other pre-degree vocational courses, as well as Higher Nationals, Foundation Degrees and first-year undergraduate modules John Bird, BSc (Hons), CEng, CSci, CMath, FITE, FIMA, FCollT, is the former Head of Applied Electronics in the Faculty of Technology at Highbury College, Portsmouth, UK More recently he has combined freelance lecturing and examining, and is the author of over 130 textbooks on engineering and mathematical subjects with worldwide sales of over one million copies He is currently lecturing at the Defence School of Marine and Air Engineering in the Defence College of Technical Training at HMS Sultan, Gosport, Hampshire, UK www.EngineeringEbooksPdf.com In Memory of Elizabeth www.EngineeringEbooksPdf.com Electrical Circuit Theory and Technology Sixth edition John Bird www.EngineeringEbooksPdf.com Sixth edition published 2017 by Routledge Park Square, Milton Park, Abingdon, Oxon OX14 4RN and by Routledge 711 Third Avenue, New York, NY 10017 Routledge is an imprint of the Taylor & Francis Group, an informa business © 2017 John Bird The right of John Bird to be identified as author of this work has been asserted by him in accordance with sections 77 and 78 of the Copyright, Designs and Patents Act 1988 All rights reserved No part of this book may be reprinted or reproduced or utilized in any form or by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying and recording, or in any information storage or retrieval system, without permission in writing from the publishers Trademark notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe First edition published by Newnes 1997 Fifth edition published by Routledge 2014 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 Names: Bird, J O., author Title: Electrical circuit theory and technology / John Bird Description: 6th ed | New York : Routledge, [2017] | Includes index Identifiers: LCCN 2016038154| ISBN 9781138673496 | ISBN 9781315561929 Subjects: LCSH: Electric circuits | Electrical engineering Classification: LCC TK454 B48 2017 | DDC 621.319/2–dc23 LC record available at https://lccn.loc.gov/2016038154 ISBN: 978-1-138-67349-6 (pbk) ISBN: 978-1-315-56192-9 (ebk) Typeset in Times by Servis Filmsetting Ltd, Stockport, Cheshire Visit the companion website: www.routledge.com/cw/bird www.EngineeringEbooksPdf.com Contents Preface Part Revision of some basic mathematics Some mathematics revision 1.1 Use of calculator and evaluating formulae 1.2 Fractions 1.3 Percentages 1.4 Ratio and proportion 1.5 Laws of indices 1.6 Brackets 1.7 Solving simple equations 1.8 Transposing formulae 1.9 Solving simultaneous equations 10 13 16 16 19 21 Further mathematics revision 2.1 Radians and degrees 2.2 Measurement of angles 2.3 Trigonometry revision 2.4 Logarithms and exponentials 2.5 Straight line graphs 2.6 Gradients, intercepts and equation of a graph 2.7 Practical straight line graphs 2.8 Calculating areas of common shapes 23 24 25 26 28 33 35 37 38 44 Part Basic electrical engineering principles 47 Units associated with basic electrical quantities 3.1 SI units 3.2 Charge 3.3 Force 3.4 Work 3.5 Power 3.6 Electrical potential and e.m.f 3.7 Resistance and conductance 49 49 50 50 51 52 53 53 Electrical power and energy 54 Summary of terms, units and their symbols 55 An introduction to electric circuits 4.1 Standard symbols for electrical components 4.2 Electric current and quantity of electricity 4.3 Potential difference and resistance 4.4 Basic electrical measuring instruments 4.5 Linear and non-linear devices 4.6 Ohm’s law 4.7 Multiples and sub-multiples 4.8 Conductors and insulators 4.9 Electrical power and energy 4.10 Main effects of electric current 4.11 Fuses 4.12 Insulation and the dangers of constant high current flow 56 Resistance variation 5.1 Resistor construction 5.2 Resistance and resistivity 5.3 Temperature coefficient of resistance 5.4 Resistor colour coding and ohmic values 65 66 66 68 70 Batteries and alternative sources of energy 6.1 Introduction to batteries 6.2 Some chemical effects of electricity 6.3 The simple cell 6.4 Corrosion 6.5 E.m.f and internal resistance of a cell 6.6 Primary cells 6.7 Secondary cells 6.8 Lithium-ion batteries 6.9 Cell capacity 6.10 Safe disposal of batteries 6.11 Fuel cells 6.12 Alternative and renewable energy sources 6.13 Solar energy 73 74 74 75 76 76 78 79 81 84 84 84 85 86 Main formulae for Part Revision of some basic mathematics 3.8 3.9 xii Revision Test www.EngineeringEbooksPdf.com 57 57 58 58 59 59 59 61 61 64 64 64 89 vi Contents Series and parallel networks 7.1 Series circuits 7.2 Potential divider 7.3 Parallel networks 7.4 Current division 7.5 Loading effect 7.6 Potentiometers and rheostats 7.7 Relative and absolute voltages 7.8 Earth potential and short circuits 7.9 Wiring lamps in series and in parallel 90 91 92 94 96 99 100 103 104 104 Capacitors and capacitance 8.1 Introduction to capacitors 8.2 Electrostatic field 8.3 Electric field strength 8.4 Capacitance 8.5 Capacitors 8.6 Electric flux density 8.7 Permittivity 8.8 The parallel plate capacitor 8.9 Capacitors connected in parallel and series 8.10 Dielectric strength 8.11 Energy stored 8.12 Practical types of capacitor 8.13 Supercapacitors 8.14 Discharging capacitors 106 107 107 108 108 109 110 110 111 Magnetic circuits 9.1 Introduction to magnetism and magnetic circuits 9.2 Magnetic fields 9.3 Magnetic flux and flux density 9.4 Magnetomotive force and magnetic field strength 9.5 Permeability and B–H curves 9.6 Reluctance 9.7 Composite series magnetic circuits 9.8 Comparison between electrical and magnetic quantities 9.9 Hysteresis and hysteresis loss 122 Revision Test 112 116 117 117 119 121 123 124 125 125 126 127 129 132 132 134 10 Electromagnetism 10.1 Magnetic field due to an electric current 10.2 Electromagnets 10.3 Force on a current-carrying conductor 10.4 Principle of operation of a simple d.c motor 10.5 Principle of operation of a moving-coil instrument 10.6 Force on a charge 135 136 137 139 142 143 143 11 Electromagnetic induction 11.1 Introduction to electromagnetic induction 11.2 Laws of electromagnetic induction 11.3 Rotation of a loop in a magnetic field 11.4 Inductance 11.5 Inductors 11.6 Energy stored 11.7 Inductance of a coil 11.8 Mutual inductance 145 146 147 150 151 152 153 153 155 12 Electrical measuring instruments and measurements 12.1 Introduction 12.2 Analogue instruments 12.3 Shunts and multipliers 12.4 Electronic instruments 12.5 The ohmmeter 12.6 Multimeters 12.7 Wattmeters 12.8 Instrument ‘loading’ effect 12.9 The oscilloscope 12.10 Virtual test and measuring instruments 12.11 Virtual digital storage oscilloscopes 12.12 Waveform harmonics 12.13 Logarithmic ratios 12.14 Null method of measurement 12.15 Wheatstone bridge 12.16 D.c potentiometer 12.17 A.c bridges 12.18 Measurement errors 158 159 159 159 161 161 162 162 162 164 169 170 173 174 176 177 177 178 179 13 Semiconductor diodes 13.1 Types of material 13.2 Semiconductor materials 13.3 Conduction in semiconductor materials 13.4 The p–n junction 13.5 Forward and reverse bias 13.6 Semiconductor diodes 13.7 Characteristics and maximum ratings 13.8 Rectification 13.9 Zener diodes 13.10 Silicon controlled rectifiers 13.11 Light emitting diodes 13.12 Varactor diodes 13.13 Schottky diodes 182 183 183 185 185 186 189 190 190 190 192 193 193 193 14 Transistors 14.1 Transistor classification 14.2 Bipolar junction transistors (BJTs) 14.3 Transistor action 14.4 Leakage current 14.5 Bias and current flow 14.6 Transistor operating configurations 195 196 196 197 198 199 199 www.EngineeringEbooksPdf.com vii Contents 14.7 14.8 14.9 14.10 14.11 14.12 14.13 14.14 14.15 Bipolar transistor characteristics Transistor parameters Current gain Typical BJT characteristics and maximum ratings Field effect transistors Field effect transistor characteristics Typical FET characteristics and maximum ratings Transistor amplifiers Load lines Revision Test 200 201 202 203 204 205 206 206 208 213 Main formulae for Part Basic electrical and electronic principles 215 Part Electrical principles and technology 217 15 D.c circuit theory 15.1 Introduction 15.2 Kirchhoff’s laws 15.3 The superposition theorem 15.4 General d.c circuit theory 15.5 Thévenin’s theorem 15.6 Constant-current source 15.7 Norton’s theorem 15.8 Thévenin and Norton equivalent networks 15.9 Maximum power transfer theorem 219 219 220 224 226 228 233 233 236 239 16 Alternating voltages and currents 16.1 Introduction 16.2 The a.c generator 16.3 Waveforms 16.4 A.c values 16.5 Electrical safety – insulation and fuses 16.6 The equation of a sinusoidal waveform 16.7 Combination of waveforms 16.8 Rectification 16.9 Smoothing of the rectified output waveform 242 243 243 244 245 248 248 251 254 255 Revision Test 17 Single-phase series a.c circuits 17.1 Purely resistive a.c circuit 17.2 Purely inductive a.c circuit 17.3 Purely capacitive a.c circuit 17.4 R–L series a.c circuit 17.5 R–C series a.c circuit 17.6 R–L–C series a.c circuit 17.7 Series resonance 17.8 17.9 17.10 17.11 Q-factor Bandwidth and selectivity Power in a.c circuits Power triangle and power factor 270 272 272 274 18 Single-phase parallel a.c circuits 18.1 Introduction 18.2 R–L parallel a.c circuit 18.3 R–C parallel a.c circuit 18.4 L–C parallel a.c circuit 18.5 LR–C parallel a.c circuit 18.6 Parallel resonance and Q-factor 18.7 Power factor improvement 277 278 278 279 280 282 285 289 19 D.c transients 19.1 Introduction 19.2 Charging a capacitor 19.3 Time constant for a C–R circuit 19.4 Transient curves for a C–R circuit 19.5 Discharging a capacitor 19.6 Camera flash 19.7 Current growth in an L–R circuit 19.8 Time constant for an L–R circuit 19.9 Transient curves for an L–R circuit 19.10 Current decay in an L–R circuit 19.11 Switching inductive circuits 19.12 The effect of time constant on a rectangular waveform 294 295 295 296 296 300 302 302 303 303 305 307 20 Operational amplifiers 20.1 Introduction to operational amplifiers 20.2 Some op amp parameters 20.3 Op amp inverting amplifier 20.4 Op amp non-inverting amplifier 20.5 Op amp voltage-follower 20.6 Op amp summing amplifier 20.7 Op amp voltage comparator 20.8 Op amp integrator 20.9 Op amp differential amplifier 20.10 Digital to analogue (D/A) conversion 20.11 Analogue to digital (A/D) conversion 309 310 311 312 314 315 315 316 317 318 320 320 Revision Test 307 322 257 258 259 259 260 261 264 266 269 21 Ways of generating electricity – the present and the future 21.1 Introduction 21.2 Generating electrical power using coal 21.3 Generating electrical power using oil 21.4 Generating electrical power using natural gas 21.5 Generating electrical power using nuclear energy www.EngineeringEbooksPdf.com 323 324 324 326 327 328 viii Contents 21.6 Generating electrical power using hydro power 21.7 Generating electrical power using pumped storage 21.8 Generating electrical power using wind 21.9 Generating electrical power using tidal power 21.10 Generating electrical power using biomass 21.11 Generating electrical power using solar energy 21.12 Harnessing the power of wind, tide and sun on an ‘energy island’ – a future possibility? 329 330 331 331 333 333 334 22 Three-phase systems 22.1 Introduction 22.2 Three-phase supply 22.3 Star connection 22.4 Delta connection 22.5 Power in three-phase systems 22.6 Measurement of power in three-phase systems 22.7 Comparison of star and delta connections 22.8 Advantages of three-phase systems 343 348 348 23 Transformers 23.1 Introduction 23.2 Transformer principle of operation 23.3 Transformer no-load phasor diagram 23.4 E.m.f equation of a transformer 23.5 Transformer on-load phasor diagram 23.6 Transformer construction 23.7 Equivalent circuit of a transformer 23.8 Regulation of a transformer 23.9 Transformer losses and efficiency 23.10 Resistance matching 23.11 Auto transformers 23.12 Isolating transformers 23.13 Three-phase transformers 23.14 Current transformers 23.15 Voltage transformers 349 350 350 352 354 356 357 358 359 360 363 365 367 367 368 369 Revision Test 336 337 337 337 340 342 24.8 24.9 24.10 24.11 24.12 24.13 24.14 24.15 24.16 D.c machine losses Efficiency of a d.c generator D.c motors Torque of a d.c machine Types of d.c motor and their characteristics The efficiency of a d.c motor D.c motor starter Speed control of d.c motors Motor cooling 25 Three-phase induction motors 25.1 Introduction 25.2 Production of a rotating magnetic field 25.3 Synchronous speed 25.4 Construction of a three-phase induction motor 25.5 Principle of operation of a three-phase induction motor 25.6 Slip 25.7 Rotor e.m.f and frequency 25.8 Rotor impedance and current 25.9 Rotor copper loss 25.10 Induction motor losses and efficiency 25.11 Torque equation for an induction motor 25.12 Induction motor torque–speed characteristics 25.13 Starting methods for induction motors 25.14 Advantages of squirrel-cage induction motors 25.15 Advantages of wound rotor induction motor 25.16 Double cage induction motor 25.17 Uses of three-phase induction motors 380 380 381 382 383 387 389 390 392 393 394 394 396 397 397 398 399 400 400 401 402 404 405 406 407 407 407 Revision Test 408 Main formulae for Part Electrical principles and technology 409 Part Advanced circuit theory and technology 411 370 24 D.c machines 24.1 Introduction 24.2 The action of a commutator 24.3 D.c machine construction 24.4 Shunt, series and compound windings 24.5 E.m.f generated in an armature winding 24.6 D.c generators 24.7 Types of d.c generator and their characteristics 371 372 372 373 373 374 375 376 26 Revision of complex numbers 26.1 Introduction 26.2 Operations involving Cartesian complex numbers 26.3 Complex equations 26.4 The polar form of a complex number www.EngineeringEbooksPdf.com 413 413 415 417 418 Contents 26.5 Multiplication and division using complex numbers in polar form 419 26.6 De Moivre’s theorem – powers and roots of complex numbers 420 27 Application of complex numbers to series a.c circuits 27.1 Introduction 27.2 Series a.c circuits 27.3 Further worked problems on series a.c circuits 28 Application of complex numbers to parallel a.c networks 28.1 Introduction 28.2 Admittance, conductance and susceptance 28.3 Parallel a.c networks 28.4 Further worked problems on parallel a.c networks 29 Power in a.c circuits 29.1 Introduction 29.2 Determination of power in a.c circuits 29.3 Power triangle and power factor 29.4 Use of complex numbers for determination of power 29.5 Power factor improvement Revision Test 423 423 424 430 435 435 436 439 443 446 446 447 449 450 454 459 30 A.c bridges 30.1 Introduction 30.2 Balance conditions for an a.c bridge 30.3 Types of a.c bridge circuit 30.4 Worked problems on a.c bridges 460 461 461 462 467 31 Series resonance and Q-factor 31.1 Introduction 31.2 Series resonance 31.3 Q-factor 31.4 Voltage magnification 31.5 Q-factors in series 31.6 Bandwidth 31.7 Small deviations from the resonant frequency 471 472 472 474 476 478 479 32 Parallel resonance and Q-factor 32.1 Introduction 32.2 The LR–C parallel network 32.3 Dynamic resistance 32.4 The LR–CR parallel network 32.5 Q-factor in a parallel network 32.6 Further worked problems on parallel resonance and Q-factor 486 486 487 488 488 489 Revision Test 483 493 496 33 Introduction to network analysis 33.1 Introduction 33.2 Solution of simultaneous equations using determinants 33.3 Network analysis using Kirchhoff’s laws 34 Mesh-current and nodal analysis 34.1 Mesh-current analysis 34.2 Nodal analysis 497 497 498 499 507 507 511 35 The superposition theorem 35.1 Introduction 35.2 Using the superposition theorem 35.3 Further worked problems on the superposition theorem 518 518 518 36 Thévenin’s and Norton’s theorems 36.1 Introduction 36.2 Thévenin’s theorem 36.3 Further worked problems on Thévenin’s theorem 36.4 Norton’s theorem 36.5 Thévenin and Norton equivalent networks 528 528 529 Revision Test 10 523 535 539 546 551 37 Delta–star and star–delta transformations 37.1 Introduction 37.2 Delta and star connections 37.3 Delta–star transformation 37.4 Star–delta transformation 552 552 552 553 561 38 Maximum power transfer theorems and impedance matching 38.1 Maximum power transfer theorems 38.2 Impedance matching 565 566 571 Revision Test 11 39 Complex waveforms 39.1 Introduction 39.2 The general equation for a complex waveform 39.3 Harmonic synthesis 39.4 Fourier series of periodic and non-periodic functions 39.5 Even and odd functions and Fourier series over any range 39.6 R.m.s value, mean value and the form factor of a complex wave 39.7 Power associated with complex waves 39.8 Harmonics in single-phase circuits 39.9 Further worked problems on harmonics in single-phase circuits 39.10 Resonance due to harmonics 39.11 Sources of harmonics www.EngineeringEbooksPdf.com 574 575 576 576 577 585 590 594 597 599 602 606 608 ix .. .Electrical Circuit Theory and Technology A fully comprehensive text for courses in electrical principles, circuit theory and electrical technology, providing 800 worked examples and over... 11 13 15 xi Preface Electrical Circuit Theory and Technology 6th Edition provides coverage for a wide range of courses that contain electrical principles, circuit theory and technology in their... Electrical Circuit Theory and Technology Sixth edition John Bird www.EngineeringEbooksPdf.com Sixth edition published 2017 by Routledge Park Square, Milton Park, Abingdon, Oxon OX14 4RN and by Routledge