Preface ........................................................................................................................................................ix
Introduction ............................................................................................................................................xi
1 Fundamentals ...........................................................................1
1.1 Units .................................................................................................................................................1
1.2 Standard Form Notation ......................................................................................................2
1.3 ‘ Scientii c ’ Notation ..................................................................................................................2
1.4 Conversion of Areas and Volumes .................................................................................4
1.5 Graphs .............................................................................................................................................5
1.6 Basic Electrical Concepts .....................................................................................................7
1.7 Communication .....................................................................................................................26
Summary of Equations ......................................................................................................29
Assignment Questions ......................................................................................................30
2 D.C. Circuits ............................................................................................. 31
2.1 Resistors in Series ..................................................................................................................31
2.2 Resistors in Parallel ...............................................................................................................35
2.3 Potential Divider ....................................................................................................................40
2.4 Current Divider .......................................................................................................................41
2.5 Series/Parallel Combinations .........................................................................................43
2.6 Kirchhof ’ s Current Law .....................................................................................................48
2.7 Kirchhof ’ s Voltage Law .....................................................................................................49
2.8 The Wheatstone Bridge Network ................................................................................55
2.9 The Wheatstone Bridge Instrument ..........................................................................63
2.10 The Slidewire Potentiometer .........................................................................................65
Summary of Equations ......................................................................................................68
Assignment Questions ......................................................................................................69
Suggested Practical Assignments ..............................................................................72
3
Electric Fields and Capacitors .................................................... 75
3.1 Coulomb ’ s Law .......................................................................................................................75
3.2 Electric Fields ...........................................................................................................................76
3.3 Electric Field Strength (E) .................................................................................................78
3.4 Electric Flux () and Flux Density (D) .......................................................................79
3.5 The Charging Process and Potential Gradient ....................................................80
3.6 Capacitance (C) ......................................................................................................................83
3.7 Capacitors ..................................................................................................................................84
3.8 Permittivity of Free Space (ε0) .......................................................................................84
3.9 Relative Permittivity (εr) .....................................................................................................84
3.10 Absolute Permittivity (ε) ...................................................................................................85
3.11 Calculating Capacitor Values ..........................................................................................85
3.12 Capacitors in Parallel ...........................................................................................................87
3.13 Capacitors in Series ..............................................................................................................89
3.14 Series/Parallel Combinations .........................................................................................92
3.15 Multiplate Capacitors .........................................................................................................95
3.16 Energy Stored ..........................................................................................................................97
3.17 Dielectric Strength and Working Voltage ...........................................................101
3.18 Capacitor Types ...................................................................................................................102
Summary of Equations ...................................................................................................105
Assignment Questions ...................................................................................................107
Suggested Practical Assignment .............................................................................110
4 Magnetic Fields and Circuits .....................................................111
4.1 Magnetic Materials ............................................................................................................111
4.2 Magnetic Fields ...................................................................................................................111
4.3 The Magnetic Circuit ........................................................................................................114
4.4 Magnetic Flux and Flux Density ................................................................................115
4.5 Magnetomotive Force (mmf ) ....................................................................................116
4.6 Magnetic Field Strength ................................................................................................117
4.7 Permeability of Free Space (0) .................................................................................118
4.8 Relative Permeability (r) ...............................................................................................119
4.9 Absolute Permeability () .............................................................................................119
4.10 Magnetisation (B/H) Curve ...........................................................................................122
4.11 Composite Series Magnetic Circuits ......................................................................126
4.12 Reluctance (S) .......................................................................................................................128
4.13 Comparison of Electrical, Magnetic and Electrostatic Quantities ........131
4.14 Magnetic Hysteresis .........................................................................................................132
4.15 Parallel Magnetic Circuits ..............................................................................................134
Summary of Equations ...................................................................................................135
Assignment Questions ...................................................................................................136
Suggested Practical Assignments ...........................................................................138
5 Electromagnetism .......................................................................... 141
5.1 Faraday ’ s Law of Electromagnetic Induction ....................................................141
5.2 Lenz ’ s Law ...............................................................................................................................144
5.3 Fleming ’ s Righthand Rule .............................................................................................144
5.4 EMF Induced in a Single Straight Conductor ...................................................147
5.5 Force on a Current-Carrying Conductor ..............................................................151
5.6 The Motor Principle ..........................................................................................................153
5.7 Force between Parallel Conductors .......................................................................156
5.8 The Moving Coil Meter ...................................................................................................158
5.9 Shunts and Multipliers ....................................................................................................162
5.10 Shunts .......................................................................................................................................162
5.11 Multipliers ...............................................................................................................................163
5.12 Figure of Merit and Loading Ef ect .........................................................................166
5.13 The Ohmmeter ....................................................................................................................170
5.14 Wattmeter ...............................................................................................................................171
5.15 Eddy Currents .......................................................................................................................172
5.16 Self and Mutual Inductance ........................................................................................174
5.17 Self-Inductance ...................................................................................................................175
5.18 Self-Inductance and Flux Linkages .........................................................................176
5.19 Factors Af ecting Inductance .....................................................................................179
5.20 Mutual Inductance ............................................................................................................180
5.21 Relationship between Self- and Mutual-Inductance ...................................182
5.22 Energy Stored .......................................................................................................................184
5.23 The Transformer Principle .............................................................................................186
5.24 Transformer Voltage and Current Ratios ..............................................................188
Summary of Equations ...................................................................................................191
Assignment Questions ...................................................................................................192
Suggested Practical Assignments ...........................................................................195
6 Alternating Quantities ................................................................ 197
6.1 Production of an Alternating Waveform .............................................................197
6.2 Angular Velocity and Frequency ..............................................................................200
6.3 Standard Expression for an Alternating Quantity ..........................................200
6.4 Average Value .......................................................................................................................203
6.5 r.m.s. Value ..............................................................................................................................205
6.6 Peak Factor .............................................................................................................................206
6.7 Form Factor ............................................................................................................................207
6.8 Rectii ers ..................................................................................................................................208
6.9 Half-wave Rectii er ............................................................................................................209
6.10 Full-wave Bridge Rectii er .............................................................................................210
6.11 Rectii er Moving Coil Meter .........................................................................................212
6.12 Phase and Phase Angle ..................................................................................................213
6.13 Phasor Representation ....................................................................................................216
6.14 Addition of Alternating Quantities ..........................................................................219
6.15 The Cathode Ray Oscilloscope ..................................................................................224
6.16 Operation of the Oscilloscope ...................................................................................226
6.17 Dual Beam Oscilloscopes ..............................................................................................228
Summary of Equations ...................................................................................................229
Assignment Questions ...................................................................................................230
Suggested Practical Assignments ...........................................................................232
7 D.C. Machines .................................................................................... 233
7.1 Motor/Generator Duality ..............................................................................................233
7.2 The Generation of d.c. Voltage ...................................................................................235
7.3 Construction of d.c. Machines ................................................................................... 238
7.4 Classii cation of Generators .........................................................................................238
7.5 Separately Excited Generator .....................................................................................239
7.6 Shunt Generator .................................................................................................................240
7.7 Series Generator .................................................................................................................242
7.8 D. C. Motors ...........................................................................................................................244
7.9 Shunt Motor ..........................................................................................................................244
7.10 Series Motor ..........................................................................................................................245
Summary of Equations ...................................................................................................247
Assignment Questions ...................................................................................................248
8
D.C. Transients ................................................................................... 249
8.1 Capacitor-Resistor Series Circuit (Charging) ......................................................249
8.2 Capacitor-Resistor Series Circuit (Discharging) ...............................................253
8.3 Inductor-Resistor Series Circuit (Connection to Supply) ...........................256
8.4 Inductor-Resistor Series Circuit (Disconnection) ............................................259
Summary of Equations ...................................................................................................260
Assignment Questions ...................................................................................................261
Suggested Practical Assignments ...........................................................................262
9
Semiconductor Theory and Devices ................................... 263
9.1 Atomic Structure ................................................................................................................263
9.2 Intrinsic (Pure) Semiconductors ................................................................................264
9.3 Electron-Hole Pair Generation and Recombination .....................................266
9.4 Conduction in Intrinsic Semiconductors ............................................................267
9.5 Extrinsic (Impure) Semiconductors ........................................................................268
9.6 n-type Semiconductor ...................................................................................................268
9.7 p-type Semiconductor ...................................................................................................270
9.8 The p-n Junction ................................................................................................................271
9.9 The p-n Junction Diode .................................................................................................272
9.10 Forward-biased Diode ....................................................................................................273
9.11 Reverse-biased Diode .....................................................................................................273
9.12 Diode Characteristics .......................................................................................................274
9.13 The Zener Diode .................................................................................................................276
Assignment Questions ...................................................................................................281
Suggested Practical Assignments ...........................................................................282
Appendix A: SI Units and Quantities ..................................................................................283
Answers to Assignment Questions .....................................................................................285
Index .......................................................................................................................................................289