Electrical Circuit Theory and Technology, Fourth Edition

753 Pages·2010·57.06 MB·English

Electrical Circuit Theory and Technology
In Memory of Elizabeth
Electrical Circuit Theory and Technology
Fourth edition
John Bird
,BSc(Hons), CEng, CSci, CMath, FIET, MIEE, FIIE,FIMA,FCollT
AMSTERDAM(cid:129)BOSTON(cid:129)HEIDELBERG(cid:129)LONDON(cid:129)NEWYORK(cid:129)OXFORD
PARIS(cid:129)SANDIEGO(cid:129)SANFRANCISCO(cid:129)SINGAPORE(cid:129)SYDNEY(cid:129)TOKYO
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Firstedition 1997
Secondedition 2001
Reprinted 2002
Revisedsecondedition 2003
Thirdedition 2007
Fourthedition 2010
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10 11 12 13 14 10 9 8 7 6 5 4 3 2 1
Contents
Preface xi 4.5 E.m.f.andinternalresistanceofacell 27
4.6 Primarycells 30
4.7 Secondarycells 31
Part1 Basicelectricalengineering
4.8 Cellcapacity 33
principles 1
4.9 Safedisposalofbatteries 33
4.10 Fuelcells 33
1 Unitsassociatedwithbasicelectrical
4.11 Alternativeandrenewableenergysources 34
quantities 3
1.1 SIunits 3
RevisionTest1 35
1.2 Charge 3
1.3 Force 4
1.4 Work 4 5 Seriesandparallelnetworks 36
1.5 Power 4 5.1 Seriescircuits 36
1.6 Electricalpotentialande.m.f. 5 5.2 Potentialdivider 37
1.7 Resistanceandconductance 6 5.3 Parallelnetworks 39
1.8 Electricalpowerandenergy 6 5.4 Currentdivision 41
1.9 Summaryofterms,unitsandtheirsymbols 7 5.5 Loadingeffect 45
5.6 Potentiometersandrheostats 46
2 Anintroductiontoelectriccircuits 8
5.7 Relativeandabsolutevoltages 48
2.1 Standardsymbolsforelectrical
5.8 Earthpotentialandshortcircuits 50
components 9
5.9 Wiringlampsinseriesandinparallel 50
2.2 Electriccurrentandquantityof
electricity 9
6 Capacitorsandcapacitance 52
2.3 Potentialdifferenceandresistance 10
6.1 Introductiontocapacitors 52
2.4 Basicelectricalmeasuring
6.2 Electrostaticfield 52
instruments 10
6.3 Electricfieldstrength 53
2.5 Linearandnon-lineardevices 11
6.4 Capacitance 54
2.6 Ohm’slaw 11
6.5 Capacitors 54
2.7 Multiplesandsub-multiples 11
6.6 Electricfluxdensity 55
2.8 Conductorsandinsulators 13
6.7 Permittivity 55
2.9 Electricalpowerandenergy 13
6.8 Theparallelplatecapacitor 56
2.10 Maineffectsofelectriccurrent 16
6.9 Capacitorsconnectedinparallelandseries 58
2.11 Fuses 16
6.10 Dielectricstrength 62
2.12 Insulationandthedangersofconstant
6.11 Energystored 62
highcurrentflow 16
6.12 Practicaltypesofcapacitor 63
3 Resistancevariation 17 6.13 Dischargingcapacitors 65
3.1 Resistorconstruction 17
3.2 Resistanceandresistivity 17 7 Magneticcircuits 66
3.3 Temperaturecoefficientofresistance 20 7.1 Introductiontomagnetismand
magneticcircuits 66
3.4 Resistorcolourcodingandohmicvalues 22
7.2 Magneticfields 67
4 Batteriesandalternativesourcesofenergy 25 7.3 Magneticfluxandfluxdensity 67
4.1 Introductiontobatteries 25 7.4 Magnetomotiveforceandmagnetic
4.2 Somechemicaleffectsofelectricity 26 fieldstrength 68
4.3 Thesimplecell 26 7.5 PermeabilityandB–Hcurves 69
4.4 Corrosion 27 7.6 Reluctance 70
vi Contents
7.7 Compositeseriesmagneticcircuits 71 11 Semiconductordiodes 121
7.8 Comparisonbetweenelectricaland 11.1 Typesofmaterial 121
magneticquantities 74 11.2 Semiconductormaterials 122
7.9 Hysteresisandhysteresisloss 75 11.3 Conductioninsemiconductormaterials 123
11.4 Thep-njunction 123
RevisionTest2 76 11.5 Forwardandreversebias 125
11.6 Semiconductordiodes 128
11.7 Characteristicsandmaximumratings 128
8 Electromagnetism 77 11.8 Rectification 129
8.1 Magneticfieldduetoanelectriccurrent 77 11.9 Zenerdiodes 129
8.2 Electromagnets 79 11.10 Siliconcontrolledrectifiers 130
8.3 Forceonacurrent-carryingconductor 80 11.11 Lightemittingdiodes 131
8.4 Principleofoperationofasimple 11.12 Varactordiodes 131
d.c.motor 84
11.13 Schottkydiodes 131
8.5 Principleofoperationofamoving
coil-instrument 84 12 Transistors 133
8.6 Forceonacharge 85 12.1 Transistorclassification 133
12.2 Bipolarjunctiontransistors(BJT) 134
12.3 Transistoraction 134
9 Electromagneticinduction 86
12.4 Leakagecurrent 135
9.1 Introductiontoelectromagneticinduction 86
12.5 Biasandcurrentflow 136
9.2 Lawsofelectromagneticinduction 87
12.6 Transistoroperatingconfigurations 137
9.3 Rotationofaloopinamagneticfield 90
12.7 Bipolartransistorcharacteristics 137
9.4 Inductance 91
12.8 Transistorparameters 138
9.5 Inductors 92
12.9 Currentgain 140
9.6 Energystored 93
12.10 TypicalBJTcharacteristicsandmaximum
9.7 Inductanceofacoil 93
ratings 140
9.8 Mutualinductance 95
12.11 Fieldeffecttransistors 141
12.12 Fieldeffecttransistorcharacteristics 142
10 Electricalmeasuringinstrumentsand 12.13 TypicalFETcharacteristicsandmaximum
measurements 97 ratings 144
10.1 Introduction 98 12.14 Transistoramplifiers 144
10.2 Analogueinstruments 98 12.15 Loadlines 146
10.3 Moving-ironinstrument 98
10.4 Themoving-coilrectifierinstrument 99 RevisionTest3 150
10.5 Comparisonofmoving-coil,moving-iron
andmoving-coilrectifierinstruments 99
MainformulaeforPart1 151
10.6 Shuntsandmultipliers 100
10.7 Electronicinstruments 101
10.8 Theohmmeter 101
Part2 Electricalprinciplesand
10.9 Multimeters 102
technology 153
10.10 Wattmeters 102
10.11 Instrument‘loading’effect 102
10.12 Theoscilloscope 105 13 D.c.circuittheory 155
10.13 Virtualtestandmeasuringinstruments 109 13.1 Introduction 155
10.14 Virtualdigitalstorageoscilloscopes 110 13.2 Kirchhoff’slaws 155
10.15 Waveformharmonics 113 13.3 Thesuperpositiontheorem 159
10.16 Logarithmicratios 114 13.4 Generald.c.circuittheory 162
10.17 Nullmethodofmeasurement 116 13.5 Thévenin’stheorem 164
10.18 Wheatstonebridge 116 13.6 Constant-currentsource 168
10.19 D.C.potentiometer 117 13.7 Norton’stheorem 169
10.20 A.C.bridges 118 13.8 ThéveninandNortonequivalentnetworks 171
10.21 Measurementerrors 118 13.9 Maximumpowertransfertheorem 175
Contents vii
14 Alternatingvoltagesandcurrents 178 18.3 Opampinvertingamplifier 247
14.1 Introduction 178 18.4 Opampnon-invertingamplifier 249
14.2 Thea.c.generator 178 18.5 Opampvoltage-follower 250
14.3 Waveforms 179 18.6 Opampsummingamplifier 250
14.4 A.c.values 180 18.7 Opampvoltagecomparator 251
14.5 Electricalsafety–insulationandfuses 183 18.8 Opampintegrator 252
14.6 Theequationofasinusoidalwaveform 184 18.9 Opampdifferentialamplifier 253
14.7 Combinationofwaveforms 186 18.10 Digitaltoanalogue(D/A)conversion 254
14.8 Rectification 190 18.11 Analoguetodigital(A/D)conversion 255
14.9 Smoothingoftherectifiedoutputwaveform 191
RevisionTest5 257
RevisionTest4 193
19 Three-phasesystems 258
15 Single-phaseseriesa.c.circuits 194 19.1 Introduction 258
15.1 Purelyresistivea.c.circuit 195 19.2 Three-phasesupply 258
15.2 Purelyinductivea.c.circuit 195 19.3 Starconnection 259
15.3 Purelycapacitivea.c.circuit 195 19.4 Deltaconnection 262
15.4 R–Lseriesa.c.circuit 197 19.5 Powerinthree-phasesystems 263
15.5 R–C seriesa.c.circuit 200 19.6 Measurementofpowerinthree-phase
15.6 R–L–Cseriesa.c.circuit 202 systems 265
15.7 Seriesresonance 205 19.7 Comparisonofstaranddeltaconnections 269
15.8 Q-factor 206 19.8 Advantagesofthree-phasesystems 270
15.9 Bandwidthandselectivity 208
15.10 Powerina.c.circuits 208 20 Transformers 271
15.11 Powertriangleandpowerfactor 209 20.1 Introduction 271
20.2 Transformerprincipleofoperation 272
16 Single-phaseparallela.c.circuits 212
20.3 Transformerno-loadphasordiagram 274
16.1 Introduction 212
20.4 E.m.f.equationofatransformer 275
16.2 R–Lparallela.c.circuit 212
20.5 Transformeron-loadphasordiagram 277
16.3 R–C parallela.c.circuit 213
20.6 Transformerconstruction 278
16.4 L–Cparallela.c.circuit 215
20.7 Equivalentcircuitofatransformer 279
16.5 LR–Cparallela.c.circuit 216
20.8 Regulationofatransformer 281
16.6 ParallelresonanceandQ-factor 219
20.9 Transformerlossesandefficiency 281
16.7 Powerfactorimprovement 223
20.10 Resistancematching 284
17 D.c.transients 229 20.11 Autotransformers 286
17.1 Introduction 229 20.12 Isolatingtransformers 288
17.2 Chargingacapacitor 229 20.13 Three-phasetransformers 288
17.3 TimeconstantforaC–Rcircuit 230 20.14 Currenttransformers 289
17.4 TransientcurvesforaC–Rcircuit 231 20.15 Voltagetransformers 290
17.5 Dischargingacapacitor 234
17.6 Cameraflash 237 RevisionTest6 291
17.7 CurrentgrowthinanL–Rcircuit 237
17.8 TimeconstantforanL–Rcircuit 237
17.9 TransientcurvesforanL–Rcircuit 238 21 D.c.machines 292
21.1 Introduction 292
17.10 CurrentdecayinanL–Rcircuit 239
21.2 Theactionofacommutator 293
17.11 Switchinginductivecircuits 242
21.3 D.c.machineconstruction 293
17.12 Theeffectoftimeconstantona
rectangularwaveform 242 21.4 Shunt,seriesandcompoundwindings 294
21.5 E.m.f.generatedinanarmaturewinding 294
18 Operationalamplifiers 244 21.6 D.c.generators 296
18.1 Introductiontooperationalamplifiers 244 21.7 Typesofd.c.generatorandtheir
18.2 Someopampparameters 246 characteristics 296
viii Contents
21.8 D.c.machinelosses 300 23.6 DeMoivre’stheorem—powersandroots
21.9 Efficiencyofad.c.generator 301 ofcomplexnumbers 342
21.10 D.c.motors 301
21.11 Torqueofad.c.machine 302 24 Applicationofcomplexnumberstoseries
a.c.circuits 344
21.12 Typesofd.c.motorandtheir
24.1 Introduction 344
characteristics 304
24.2 Seriesa.c.circuits 344
21.13 Theefficiencyofad.c.motor 308
24.3 Furtherworkedproblemsonseries
21.14 D.c.motorstarter 310
a.c.circuits 351
21.15 Speedcontrolofd.c.motors 310
21.16 Motorcooling 313
25 Applicationofcomplexnumberstoparallel
a.c.networks 356
22 Three-phaseinductionmotors 314
25.1 Introduction 356
22.1 Introduction 314
25.2 Admittance,conductanceandsusceptance 356
22.2 Productionofarotatingmagneticfield 315
25.3 Parallela.c.networks 360
22.3 Synchronousspeed 316
25.4 Furtherworkedproblemsonparallel
22.4 Constructionofathree-phaseinduction
a.c.networks 363
motor 317
22.5 Principleofoperationofathree-phase 26 Powerina.c.circuits 367
inductionmotor 318 26.1 Introduction 367
22.6 Slip 318 26.2 Determinationofpowerina.c.circuits 367
22.7 Rotore.m.f.andfrequency 320 26.3 Powertriangleandpowerfactor 369
22.8 Rotorimpedanceandcurrent 320 26.4 Useofcomplexnumbersfor
22.9 Rotorcopperloss 321 determinationofpower 370
22.10 Inductionmotorlossesandefficiency 321 26.5 Powerfactorimprovement 375
22.11 Torqueequationforaninductionmotor 323
22.12 Inductionmotortorque–speed RevisionTest8 380
characteristics 325
22.13 Startingmethodsforinductionmotors 326 27 A.c.bridges 381
22.14 Advantagesofsquirrel-cageinduction 27.1 Introduction 381
motors 328 27.2 Balanceconditionsforana.c.bridge 381
22.15 Advantagesofwoundrotorinduction 27.3 Typesofa.c.bridgecircuit 382
motor 328
27.4 Workedproblemsona.c.bridges 387
22.16 Doublecageinductionmotor 328
22.17 Usesofthree-phaseinductionmotors 328 28 SeriesresonanceandQ-factor 391
28.1 Introduction 391
RevisionTest7 329 28.2 Seriesresonance 391
28.3 Q-factor 394
28.4 Voltagemagnification 395
MainformulaeforPart2 330
28.5 Q-factorsinseries 398
28.6 Bandwidth 399
28.7 Smalldeviationsfromtheresonant
frequency 403
Part3 Advanced circuittheory
29 ParallelresonanceandQ-factor 405
andtechnology 333
29.1 Introduction 405
29.2 TheLR–C parallelnetwork 406
23 Revisionofcomplexnumbers 335
29.3 Dynamicresistance 406
23.1 Introduction 335
29.4 TheLR–CRparallelnetwork 407
23.2 OperationsinvolvingCartesiancomplex
29.5 Q-factorinaparallelnetwork 407
numbers 336
29.6 Furtherworkedproblemsonparallel
23.3 Complexequations 338
resonanceandQ-factor 412
23.4 Thepolarformofacomplexnumber 339
23.5 Multiplicationanddivisionusingcomplex
RevisionTest9 415
numbersinpolarform 340
Contents ix
30 Introductiontonetworkanalysis 416 36.10 Resonanceduetoharmonics 523
30.1 Introduction 416 36.11 Sourcesofharmonics 525
30.2 Solutionofsimultaneousequationsusing
determinants 417
37 Anumericalmethodofharmonicanalysis 529
30.3 NetworkanalysisusingKirchhoff’slaws 418
37.1 Introduction 529
31 Mesh-currentandnodalanalysis 425 37.2 Harmonicanalysisondatagivenintabular
31.1 Mesh-currentanalysis 425 orgraphicalform 529
31.2 Nodalanalysis 429 37.3 Complexwaveformconsiderations 532
32 Thesuperpositiontheorem 436
32.1 Introduction 436 38 Magneticmaterials 536
32.2 Usingthesuperpositiontheorem 436 38.1 Revisionoftermsandunitsusedwith
magneticcircuits 536
32.3 Furtherworkedproblemsonthe
superpositiontheorem 441 38.2 Magneticpropertiesofmaterials 537
38.3 Hysteresisandhysteresisloss 539
33 Thévenin’sandNorton’stheorems 445 38.4 Eddycurrentloss 542
33.1 Introduction 445 38.5 Separationofhysteresisandeddycurrent
33.2 Thévenin’stheorem 445 losses 545
33.3 FurtherworkedproblemsonThévenin’s 38.6 Non-permanentmagneticmaterials 547
theorem 452 38.7 Permanentmagneticmaterials 549
33.4 Norton’stheorem 456
33.5 ThéveninandNortonequivalentnetworks 462
RevisionTest12 550
RevisionTest10 468
39 Dielectricsanddielectricloss 551
34 Delta-starandstar-deltatransformations 469 39.1 Electricfields,capacitanceandpermittivity 551
34.1 Introduction 469 39.2 Polarization 551
34.2 Deltaandstarconnections 469 39.3 Dielectricstrength 552
34.3 Delta-startransformation 469 39.4 Thermaleffects 553
34.4 Star-deltatransformation 478 39.5 Mechanicalproperties 553
39.6 Typesofpracticalcapacitor 553
35 Maximumpowertransfertheoremsand
39.7 Liquiddielectricsandgasinsulation 553
impedancematching 481
39.8 Dielectriclossandlossangle 554
35.1 Maximumpowertransfertheorems 481
35.2 Impedancematching 487
40 Fieldtheory 557
40.1 Fieldplottingbycurvilinearsquares 557
RevisionTest11 490
40.2 Capacitancebetweenconcentriccylinders 561
40.3 Capacitanceofanisolatedtwinline 566
36 Complexwaveforms 491
40.4 Energystoredinanelectricfield 569
36.1 Introduction 491
40.5 Inducede.m.f.andinductance 571
36.2 Thegeneralequationforacomplex
40.6 Inductanceofaconcentriccylinder(or
waveform 492
coaxialcable) 571
36.3 Harmonicsynthesis 493
40.7 Inductanceofanisolatedtwinline 574
36.4 Fourierseriesofperiodicandnon-periodic
40.8 Energystoredinanelectromagneticfield 576
functions 500
36.5 EvenandoddfunctionsandFourierseries
overanyrange 505 41 Attenuators 579
36.6 Rmsvalue,meanvalueandtheform 41.1 Introduction 579
factorofacomplexwave 509 41.2 Characteristicimpedance 580
36.7 Powerassociatedwithcomplexwaves 513 41.3 Logarithmicratios 581
36.8 Harmonicsinsingle-phasecircuits 515 41.4 SymmetricalT-andπ-attenuators 583
36.9 Furtherworkedproblemsonharmonics 41.5 Insertionloss 589
insingle-phasecircuits 519 41.6 AsymmetricalT-andπ-sections 592