Electrical circuit theory and technology, Third Edition (Electrical Circuit Theory and Technology)

694 Pages·2007·8.17 MB·English

by  John Bird

Prelims-H8139.tex 30/3/2007 9:16 pagei
Electrical Circuit Theory and Technology
Prelims-H8139.tex 30/3/2007 9:16 pageii
In Memory of Elizabeth
Prelims-H8139.tex 30/3/2007 9:16 pageiii
Electrical Circuit Theory and Technology
Third edition
John Bird BSc(Hons), CEng, CSci, CMath, FIET, MIEE,
FIIE, FIMA, FCollT
AMSTERDAM (cid:127) BOSTON (cid:127) HEIDELBERG (cid:127) LONDON (cid:127) NEW YORK (cid:127) OXFORD
PARIS (cid:127) SAN DIEGO (cid:127) SAN FRANCISCO (cid:127) SINGAPORE (cid:127) SYDNEY (cid:127) TOKYO
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Prelims-H8139.tex 30/3/2007 9:16 pagev
Contents
Preface xi 4.9 Safedisposalofbatteries 26
4.10 Fuelcells 26
Part1 Basicelectricalengineering
4.11 Alternative and renewable energy
principles 1 sources 26
Revisiontest1 27
1 Unitsassociatedwithbasicelectrical
quantities 3
1.1 SIunits 3 5 Seriesandparallelnetworks 28
1.2 Charge 3 5.1 Seriescircuits 28
1.3 Force 4 5.2 Potentialdivider 29
1.4 Work 4 5.3 Parallelnetworks 31
1.5 Power 4 5.4 Currentdivision 33
1.6 Electricalpotentialande.m.f. 5 5.5 Relativeandabsolutevoltages 36
1.7 Resistanceandconductance 5 5.6 Wiringlampsinseriesandinparallel 38
1.8 Electricalpowerandenergy 5
1.9 Summary of terms, units and their
6 Capacitorsandcapacitance 39
symbols 6
6.1 Introductiontocapacitors 39
2 Anintroductiontoelectriccircuits 7 6.2 Electrostaticfield 39
2.1 Standardsymbolsforelectrical 6.3 Electricfieldstrength 40
components 7 6.4 Capacitance 40
2.2 Electriccurrentandquantityof 6.5 Capacitors 41
electricity 7 6.6 Electricfluxdensity 42
2.3 Potentialdifferenceandresistance 8 6.7 Permittivity 42
2.4 Basicelectricalmeasuring 6.8 Theparallelplatecapacitor 43
instruments 8 6.9 Capacitorsconnectedinparalleland
2.5 Linearandnon-lineardevices 9 series 45
2.6 Ohm’slaw 9 6.10 Dielectricstrength 48
2.7 Multiplesandsub-multiples 9 6.11 Energystored 48
2.8 Conductorsandinsulators 11 6.12 Practicaltypesofcapacitor 49
2.9 Electricalpowerandenergy 11 6.13 Dischargingcapacitors 51
2.10 Maineffectsofelectriccurrent 13
2.11 Fuses 13
7 Magneticcircuits 52
7.1 Introductiontomagnetismand
3 Resistancevariation 15
magneticcircuits 52
3.1 Resistanceandresistivity 15
7.2 Magneticfields 52
3.2 Temperaturecoefficientofresistance 17
7.3 Magneticfluxandfluxdensity 53
7.4 Magnetomotiveforceandmagnetic
4 Batteries 20
fieldstrength 54
4.1 Introductiontobatteries 20
7.5 PermeabilityandB–H curves 54
4.2 Somechemicaleffectsofelectricity 20
7.6 Reluctance 56
4.3 Thesimplecell 21
7.7 Compositeseriesmagneticcircuits 57
4.4 Corrosion 22
7.8 Comparison between electrical and
4.5 E.m.f.andinternalresistanceofacell 22
magneticquantities 60
4.6 Primarycells 24
7.9 Hysteresisandhysteresisloss 60
4.7 Secondarycells 24
4.8 Cellcapacity 26 Revisiontest2 61
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vi Contents
8 Electromagnetism 62 11.3 Conductioninsemiconductor
8.1 Magnetic field due to an electric materials 104
current 62 11.4 Thep-njunction 104
8.2 Electromagnets 64 11.5 Forwardandreversebias 105
8.3 Forceonacurrent-carrying 11.6 Semiconductordiodes 108
conductor 65 11.7 Characteristicsandmaximum
8.4 Principleofoperationofasimple ratings 109
d.c.motor 68 11.8 Rectification 109
8.5 Principleofoperationofamoving- 11.9 Zenerdiodes 110
coilinstrument 68 11.10 Siliconcontrolledrectifiers 111
8.6 Forceonacharge 69 11.11 Lightemittingdiodes 111
11.12 Varactordiodes 111
11.13 Schottkydiodes 112
9 Electromagneticinduction 70
9.1 Introduction to electromagnetic 12 Transistors 113
induction 70 12.1 Transistorclassification 113
9.2 Lawsofelectromagneticinduction 71 12.2 Bipolarjunctiontransistors(BJT) 113
9.3 Rotation of a loop in a magnetic 12.3 Transistoraction 114
field 73 12.4 Leakagecurrent 115
9.4 Inductance 74 12.5 Biasandcurrentflow 115
9.5 Inductors 75 12.6 Transistoroperating
9.6 Energystored 76 configurations 116
9.7 Inductanceofacoil 76 12.7 Bipolartransistorcharacteristics 117
9.8 Mutualinductance 78 12.8 Transistorparameters 118
12.9 Currentgain 119
10 Electricalmeasuringinstrumentsand 12.10 TypicalBJTcharacteristicsand
measurements 80 maximumratings 120
10.1 Introduction 80 12.11 Fieldeffecttransistors 121
10.2 Analogueinstruments 80 12.12 Fieldeffecttransistor
10.3 Moving-ironinstrument 81 characteristics 121
10.4 Themoving-coilrectifier 12.13 Typical FET characteristics and
instrument 81 maximumratings 123
10.5 Comparisonofmoving-coil, 12.14 Transistoramplifiers 124
moving-ironandmoving-coil 12.15 Loadlines 125
rectifierinstruments 82
Revisiontest3 129
10.6 Shuntsandmultipliers 82
10.7 Electronicinstruments 84 MainformulaeforPart1 130
10.8 Theohmmeter 84
10.9 Multimeters 84 Part2 Electricalprinciplesand
10.10 Wattmeters 85
technology 131
10.11 Instrument‘loading’effect 85
10.12 Theoscilloscope 87
13 D.c.circuittheory 133
10.13 Virtualtestandmeasuring
13.1 Introduction 133
instruments 91
13.2 Kirchhoff’slaws 133
10.14 Virtualdigitalstorage
13.3 Thesuperpositiontheorem 137
oscilloscopes 92
13.4 Generald.c.circuittheory 140
10.15 Waveformharmonics 95
13.5 Thévenin’stheorem 142
10.16 Logarithmicratios 96
13.6 Constant-currentsource 146
10.17 Nullmethodofmeasurement 98
13.7 Norton’stheorem 146
10.18 Wheatstonebridge 98
13.8 Thévenin and Norton equivalent
10.19 D.C.potentiometer 99
networks 149
10.20 A.C.bridges 99
13.9 Maximumpowertransfertheorem 152
10.21 Measurementerrors 100
14 Alternatingvoltagesandcurrents 155
11 Semiconductordiodes 102 14.1 Introduction 155
11.1 Typesofmaterial 102 14.2 Thea.c.generator 155
11.2 Semiconductormaterials 102 14.3 Waveforms 156
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Contents vii
14.4 A.c.values 157 18.11 Analoguetodigital(A/D)
14.5 Theequationofasinusoidal conversion 222
waveform 160
Revisiontest5 224
14.6 Combinationofwaveforms 163
14.7 Rectification 166
19 Three-phasesystems 225
Revisiontest4 167 19.1 Introduction 225
19.2 Three-phasesupply 225
15 Single-phaseseriesa.c.circuits 168 19.3 Starconnection 226
15.1 Purelyresistivea.c.circuit 168 19.4 Deltaconnection 228
15.2 Purelyinductivea.c.circuit 168 19.5 Powerinthree-phasesystems 230
15.3 Purelycapacitivea.c.circuit 169 19.6 Measurementofpowerinthree-
15.4 R–Lseriesa.c.circuit 170 phasesystems 231
15.5 R–Cseriesa.c.circuit 173 19.7 Comparisonofstaranddelta
15.6 R–L–Cseriesa.c.circuit 174 connections 235
15.7 Seriesresonance 178 19.8 Advantagesofthree-phase
15.8 Q-factor 179 systems 236
15.9 Bandwidthandselectivity 180
15.10 Powerina.c.circuits 181
15.11 Powertriangleandpowerfactor 182 20 Transformers 237
20.1 Introduction 237
16 Single-phaseparallela.c.circuits 185 20.2 Transformerprincipleofoperation 237
16.1 Introduction 185 20.3 Transformerno-loadphasor
16.2 R–Lparallela.c.circuit 185 diagram 239
16.3 R–Cparallela.c.circuit 186 20.4 E.m.f.equationofatransformer 241
16.4 L–Cparallela.c.circuit 187 20.5 Transformeron-loadphasor
16.5 LR–Cparallela.c.circuit 189 diagram 242
16.6 ParallelresonanceandQ-factor 191 20.6 Transformerconstruction 244
16.7 Powerfactorimprovement 195 20.7 Equivalentcircuitofatransformer 244
20.8 Regulationofatransformer 246
17 D.c.transients 199 20.9 Transformerlossesandefficiency 246
17.1 Introduction 199 20.10 Resistancematching 249
17.2 Chargingacapacitor 199 20.11 Autotransformers 251
17.3 TimeconstantforaC–Rcircuit 200 20.12 Isolatingtransformers 253
17.4 TransientcurvesforaC–Rcircuit 200 20.13 Three-phasetransformers 253
17.5 Dischargingacapacitor 204 20.14 Currenttransformers 254
17.6 Cameraflash 206 20.15 Voltagetransformers 255
17.7 CurrentgrowthinanL–Rcircuit 206
Revisiontest6 256
17.8 TimeconstantforanL–Rcircuit 207
17.9 TransientcurvesforanL–Rcircuit 207
17.10 CurrentdecayinanL–Rcircuit 208 21 D.c.machines 257
17.11 Switchinginductivecircuits 211 21.1 Introduction 257
17.12 Theeffectoftimeconstantona 21.2 Theactionofacommutator 257
rectangularwaveform 211 21.3 D.c.machineconstruction 258
21.4 Shunt,seriesandcompound
18 Operationalamplifiers 212 windings 258
18.1 Introductiontooperational 21.5 E.m.f. generated in an armature
amplifiers 212 winding 259
18.2 Someopampparameters 213 21.6 D.c.generators 260
18.3 Opampinvertingamplifier 214 21.7 Typesofd.c.generatorandtheir
18.4 Opampnon-invertingamplifier 216 characteristics 261
18.5 Opampvoltage-follower 217 21.8 D.c.machinelosses 264
18.6 Opampsummingamplifier 217 21.9 Efficiencyofad.c.generator 265
18.7 Opampvoltagecomparator 218 21.10 D.c.motors 265
18.8 Opampintegrator 219 21.11 Torqueofad.c.machine 266
18.9 Opampdifferentialamplifier 220 21.12 Typesofd.c.motorandtheir
18.10 Digitaltoanalogue(D/A) characteristics 268
conversion 221 21.13 Theefficiencyofad.c.motor 271
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viii Contents
25 Applicationofcomplexnumberstoparallel
21.14 D.c.motorstarter 273
a.c.networks 316
21.15 Speedcontrolofd.c.motors 274
25.1 Introduction 316
21.16 Motorcooling 276
25.2 Admittance,conductanceand
susceptance 316
22 Three-phaseinductionmotors 277
25.3 Parallela.c.networks 319
22.1 Introduction 277
25.4 Furtherworkedproblemson
22.2 Productionofarotatingmagnetic
parallela.c.networks 323
field 277
22.3 Synchronousspeed 279 26 Powerina.c.circuits 327
22.4 Constructionofathree-phase 26.1 Introduction 327
inductionmotor 280 26.2 Determinationofpowerin
22.5 Principle of operation of a three- a.c.circuits 327
phaseinductionmotor 280 26.3 Powertriangleandpowerfactor 329
22.6 Slip 281 26.4 Useofcomplexnumbersfor
22.7 Rotore.m.f.andfrequency 282 determinationofpower 330
22.8 Rotorimpedanceandcurrent 283 26.5 Powerfactorimprovement 334
22.9 Rotorcopperloss 283
Revisiontest8 339
22.10 Inductionmotorlossesand
efficiency 284 27 A.c.bridges 340
22.11 Torque equation for an induction 27.1 Introduction 340
motor 285 27.2 Balance conditions for an a.c.
22.12 Inductionmotortorque–speed bridge 340
characteristics 287 27.3 Typesofa.c.bridgecircuit 341
22.13 Starting methods for induction 27.4 Workedproblemsona.c.bridges 345
motors 288
22.14 Advantagesofsquirrel-cage 28 SeriesresonanceandQ-factor 349
inductionmotors 290 28.1 Introduction 349
22.15 Advantagesofwoundrotor 28.2 Seriesresonance 349
inductionmotor 290 28.3 Q-factor 351
22.16 Doublecageinductionmotor 290 28.4 Voltagemagnification 353
22.17 Usesofthree-phaseinduction 28.5 Q-factorsinseries 355
motors 290 28.6 Bandwidth 356
28.7 Smalldeviationsfromtheresonant
Revisiontest7 291
frequency 360
MainformulaeforPart2 292
29 ParallelresonanceandQ-factor 362
29.1 Introduction 362
Part3 Advancedcircuittheoryand
29.2 TheLR–Cparallelnetwork 363
technology 295
29.3 Dynamicresistance 363
29.4 TheLR–CRparallelnetwork 363
23 Revisionofcomplexnumbers 297
29.5 Q-factorinaparallelnetwork 364
23.1 Introduction 297
29.6 Furtherworkedproblemson
23.2 OperationsinvolvingCartesian
parallelresonanceandQ-factor 368
complexnumbers 298
Revisiontest9 371
23.3 Complexequations 300
23.4 Thepolarformofacomplex 30 Introductiontonetworkanalysis 372
number 301 30.1 Introduction 372
23.5 Multiplicationanddivisionusing 30.2 Solutionofsimultaneous
complexnumbersinpolarform 301 equationsusingdeterminants 372
23.6 De Moivre’s theorem — powers 30.3 Networkanalysisusing
androotsofcomplexnumbers 303 Kirchhoff’slaws 374
24 Applicationofcomplexnumberstoseries 31 Mesh-currentandnodalanalysis 381
a.c.circuits 305 31.1 Mesh-currentanalysis 381
24.1 Introduction 305 31.2 Nodalanalysis 385
24.2 Seriesa.c.circuits 305
24.3 Furtherworkedproblemsonseries 32 Thesuperpositiontheorem 391
a.c.circuits 311 32.1 Introduction 391
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Contents ix
32.2 Usingthesuperpositiontheorem 391 38.3 Hysteresisandhysteresisloss 488
32.3 Further worked problems on the 38.4 Eddycurrentloss 491
superpositiontheorem 396 38.5 Separationofhysteresisandeddy
currentlosses 494
33 Thévenin’sandNorton’stheorems 400 38.6 Non-permanentmagnetic
33.1 Introduction 400 materials 496
33.2 Thévenin’stheorem 400 38.7 Permanentmagneticmaterials 497
33.3 Further worked problems on
Revisiontest12 499
Thévenin’stheorem 406
33.4 Norton’stheorem 410 39 Dielectricsanddielectricloss 500
33.5 Thévenin and Norton equivalent 39.1 Electricfields,capacitanceand
networks 417 permittivity 500
Revisiontest10 422 39.2 Polarization 500
39.3 Dielectricstrength 501
34 Delta-starandstar-deltatransformations 423 39.4 Thermaleffects 502
34.1 Introduction 423 39.5 Mechanicalproperties 502
34.2 Deltaandstarconnections 423 39.6 Typesofpracticalcapacitor 502
34.3 Delta-startransformation 423 39.7 Liquiddielectricsandgas
34.4 Star-deltatransformation 431 insulation 502
39.8 Dielectriclossandlossangle 502
35 Maximumpowertransfertheoremsand
impedancematching 435
40 Fieldtheory 506
35.1 Maximumpowertransfer
40.1 Fieldplottingbycurvilinear
theorems 435
squares 506
35.2 Impedancematching 440
40.2 Capacitancebetweenconcentric
Revisiontest11 443 cylinders 510
40.3 Capacitance of an isolated twin
36 Complexwaveforms 444 line 514
36.1 Introduction 444 40.4 Energystoredinanelectricfield 517
36.2 Thegeneralequationfora 40.5 Inducede.m.f.andinductance 519
complexwaveform 444 40.6 Inductanceofaconcentric
36.3 Harmonicsynthesis 446 cylinder(orcoaxialcable) 519
36.4 Fourierseriesofperiodicand 40.7 Inductanceofanisolatedtwinline 522
non-periodicfunctions 453 40.8 Energystoredinanelectro-
36.5 Evenandoddfunctionsand magneticfield 524
Fourierseriesoveranyrange 457
36.6 Rmsvalue,meanvalueandthe 41 Attenuators 527
formfactorofacomplexwave 462 41.1 Introduction 527
36.7 Power associated with complex 41.2 Characteristicimpedance 528
waves 465 41.3 Logarithmicratios 529
36.8 Harmonicsinsingle-phasecircuits 467 41.4 SymmetricalT-andπ-attenuators 531
36.9 Furtherworkedproblemson 41.5 Insertionloss 536
harmonicsinsingle-phasecircuits 471 41.6 AsymmetricalT-andπ-sections 539
36.10 Resonanceduetoharmonics 474 41.7 TheL-sectionattenuator 542
36.11 Sourcesofharmonics 476 41.8 Two-portnetworksincascade 544
41.9 ABCDparameters 546
37 Anumericalmethodofharmonicanalysis 480 41.10 ABCDparametersfornetworks 550
37.1 Introduction 480 41.11 Characteristicimpedanceinterms
37.2 Harmonic analysis on data given ofABCDparameters 555
intabularorgraphicalform 480 Revisiontest13 557
37.3 Complexwaveform
considerations 483 42 Filternetworks 558
42.1 Introduction 558
38 Magneticmaterials 486 42.2 Basictypesoffiltersections 558
38.1 Revision of terms and units used 42.3 The characteristic impedance and
withmagneticcircuits 486 theattenuationoffiltersections 560
38.2 Magneticpropertiesofmaterials 487 42.4 Laddernetworks 561