كتاب أساسيات الهندسة الكهربية – Basic Electrical Engineering

أساسيات الهندسة الكهربية
Basic Electrical Engineering
For B.E./B.Tech. and Other Engineering Examinations
V. K. Mehta, Rohit Mehta
Contents
Chapter Pages

1. Basic Concepts 1 – 35
   Nature of Electricity – Unit of Charge – The Electron – Energy of an Electron – Valence Electrons –
   Free Electrons – Electric Current – Electric Current is a Scalar Quantity – Types of Electric
   Current – Mechanism of Current Conduction in Metals – Relation Between Current and Drift
   Velocity – Electric Potential – Potential Difference – Maintaining Potential Difference –
   Concept of E.M.F. and Potential Difference – Potential Rise and Potential Drop – Resistance –
   Factors Upon Which Resistance Depends – Specific Resistance or Resistivity – Conductance –
   Types of Resistors – Effect of Temperature on Resistance – Temperature Co-efficient of
   Resistance – Graphical Determination of a – Temperature Co-efficient at Various Temperatures –
   Summary of Temperature Co-efficient Relations – Variation of Resistivity With Temperature –
   Ohm’s Law – Non-ohmic Conductors – Electric Power – Electrical Energy – Use of Power and
   Energy Formulas – Power Rating of a Resistor – Non-linear Resistors – Objective Questions.
2. D.C. Circuits 36 – 105
   D.C. Circuit – D.C. Series Circuit – D.C. Parallel Circuit – Main Features of Parallel Circuits –
   Two Resistances in Parallel – Advantages of Parallel Circuits – Applications of Parallel
   Circuits – D.C. Series-Parallel Circuits – Applications of Series-Parallel Circuits – Internal
   Resistance of a Supply – Equivalent Resistance – Open Circuits – Short Circuits – Duality
   Between Series and Parallel Circuits – Wheatstone Bridge – Complex Circuits – Kirchhoff’s
   Laws – Sign Convention – Illustration of Kirchhoff’s Laws – Method to Solve Circuits by
   Kirchhoff’s Laws – Matrix Algebra – Voltage and Current Sources – Ideal Voltage Source
   or Constant-Voltage Source – Real Voltage Source – Ideal Current Source – Real Current
   Source – Source Conversion – Independent Voltage and Current Sources – Dependent Voltage
   and Current Sources – Circuits With Dependent-Sources – Ground – Voltage Divider Circuit –
   Objective Questions.
3. D.C. Network Theorems 106 – 238
   Network Terminology – Network Theorems and Techniques – Important Points About Network
   Analysis – Maxwell’s Mesh Current Method – Shortcut Procedure for Network Analysis by
   Mesh Currents – Nodal Analysis – Nodal Analysis with Two Independent Nodes – Shortcut
   Method for Nodal Analysis – Superposition Theorem – Thevenin’s Theorem – Procedure
   for Finding Thevenin Equivalent Circuit – Thevenin Equivalent Circuit – Advantages
   of Thevenin’s Theorem – Norton’s Theorem – Procedure for Finding Norton Equivalent
   Circuit – Norton Equivalent Circuit – Maximum Power Transfer Theorem – Proof of
   Maximum Power Transfer Theorem – Applications of Maximum Power Transfer Theorem –
   Reciprocity Theorem – Millman’s Theorem – Compensation Theorem – Delta/Star and Star/
   Delta Transformation – Delta/Star Transformation – Star/Delta Transformation – Tellegen’s
   Theorem – Objective Questions.
4. Units – Work, Power and Energy 239 – 259
   International System of Units – Important Physical Quantities – Units of Work or Energy –
   Some Cases of Mechanical Work or Energy – Electrical Energy – Thermal Energy – Units
   of Power – Efficiency of Electric Device – Harmful Effects of Poor Efficiency – Heating
   Effect of Electric Current – Heat Produced in a Conductor by Electric Current – Mechanical
   Equivalent of Heat (J) – Objective Questions.
5. Electrostatics 260 – 294
   Electrostatics – Importance of Electrostatics – Methods of Charging a Capacitor – Coulomb’s Laws
   of Electrostatics – Absolute and Relative Permittivity – Coulomb’s Law in Vector Form – The
   (v)Superposition Principle – Electric Field – Properties of Electric Lines of Force – Electric Intensity
   or Field Strength (E) – Electric Flux (ψ) – Electric Flux Density (D) – Gauss’s Theorem –
   Proof of Gauss’s Law – Electric Potential Energy – Electric Potential – Electric Potential
   Difference – Potential at a Point Due to a Point Charge – Potential at a Point Due to Group of
   Point Charges – Behaviour of Metallic Conductors in Electric Field – Potential of a Charged
   Conducting Sphere – Potential Gradient – Breakdown Voltage or Dielectric Strength – Uses of
   Dielectrics – Refraction of Electric Flux – Equipotential Surface – Motion of a Charged Particle
   in Uniform Electric Field – Objective Questions.
6. Capacitance and Capacitors 295 – 349
   Capacitor – How does a Capacitor Store Charge ? – Capacitance – Factors Affecting Capacitance –
   Dielectric Constant or Relative Permittivity – Capacitance of an Isolated Conducting Sphere –
   Capacitance of Spherical Capacitor – Capacitance of Parallel-Plate Capacitor with Uniform
   Medium – Parallel-Plate Capacitor with Composite Medium – Special Cases of Parallel-Plate
   Capacitor – Multiplate Capacitor – Cylindrical Capacitor – Potential Gradient in a Cylindrical
   Capacitor – Most Economical Conductor Size in a Cable – Capacitance Between Parallel
   Wires – Insulation Resistance of a Cable Capacitor – Leakage Resistance of a Capacitor – Voltage
   Rating of a Capacitor – Capacitors in Series – Capacitors in Parallel – Joining Two Charged
   Capacitors – Energy Stored in a Capacitor – Energy Density of Electric Field – Force on Charged
   Plates – Behaviour of Capacitor in a D.C. Circuit – Charging of a Capacitor – Time Constant –
   Discharging of a Capacitor – Transients in D.C. Circuits – Transient Relations During Charging
   Discharging of Capacitor – Objective Questions.
7. Magnetism and Electromagnetism 350 – 385
   Poles of a Magnet – Laws of Magnetic Force – Magnetic Field – Magnetic Flux – Magnetic Flux
   Density – Magnetic Intensity or Magnetising Force (H) – Magnetic Potential – Absolute and
   Relative Permeability – Relation Between B and H – Important Terms – Relation Between mr
   and χm – Refraction of Magnetic Flux – Molecular Theory of Magnetism – Modern View about
   Magnetism – Magnetic Materials – Electromagnetism – Magnetic Effect of Electric Current –
   Typical Electromagnetic Fields – Magnetising Force (H) Produced by Electric Current – Force
   on Current-Carrying Conductor Placed in a Magnetic Field – Ampere’s Work Law or Ampere’s
   Circuital Law – Applications of Ampere’s Work Law – Biot-Savart Law – Applications of
   Biot-Savart Law – Magnetic Field at the Centre of Current-Carrying Circular Coil – Magnetic
   Field Due to Straight Conductor Carrying Current – Magnetic Field on the Axis of Circular Coil
   Carrying Current – Force Between Current-Carrying Parallel Conductors – Magnitude of Mutual
   Force – Definition of Ampere – Objective Questions.
8. Magnetic Circuits 386 – 429
   Magnetic Circuit – Analysis of Magnetic Circuit – Important Terms – Comparison Between
   Magnetic and Electric Circuits – Calculation of Ampere-Turns – Series Magnetic Circuits – Air
   Gaps in Magnetic Circuits – Parallel Magnetic Circuits – Magnetic Leakage and Fringing –
   Solenoid – B-H Curve – Magnetic Calculations From B-H Curves – Determination of B/H or
   Magnetisation Curve – B-H Curve by Ballistic Galvanometer – B-H Curve by Fluxmeter –
   Magnetic Hysteresis – Hysteresis Loss – Calculation of Hysteresis Loss – Factors Affecting
   the Shape and Size of Hysteresis Loop – Importance of Hysteresis Loop – Applications of
   Ferromagnetic Materials – Steinmetz Hysteresis Law – Comparison of Electrostatics and
   Electromagnetic Terms – Objective Questions.
9. Electromagnetic Induction 430 – 480
   Electromagnetic Induction – Flux Linkages – Faraday’s Laws of Electromagnetic Induction –
   Direction of Induced E.M.F. and Current – Induced E.M.F. – Dynamically Induced E.M.F. –
   Statically Induced E.M.F. – Self-inductance (L) – Magnitude of Self-induced E.M.F. – Expressions
   for Self-inductance – Magnitude of Mutually Induced E.M.F. – Expressions for Mutual
   Inductance – Co-efficient of Coupling – Inductors in Series – Inductors in Parallel with no Mutual
   Inductance – Inductors in Parallel with Mutual Inductance – Energy Stored in a Magnetic Field –
   (vi)Magnetic Energy Stored Per Unit Volume – Lifting Power of a Magnet – Closing and Breaking an
   Inductive Circuit – Rise of Current in an Inductive Circuit – Time Constant – Decay of Current
   in an Inductive Circuit – Eddy Current Loss – Formula for Eddy Current Power Loss – Objective
   Questions.
10. Chemical Effects of Electric Current 481 – 520
    Electric Behaviour of Liquids – Electrolytes – Mechanism of Ionisation – Electrolysis – Back
    e.m.f. or Polarisation Potential – Faraday’s Laws of Electrolysis – Relation Between E and Z –
    Deduction of Faraday’s Laws of Electrolysis – Practical Applications of Electrolysis – Cell – Types
    of Cells – Lead-Acid Cell – Chemical Changes During Discharging – Chemical Changes During
    Recharging – Formation of Plates of Lead-acid Cells – Construction of a Lead-acid Battery –
    Characteristics of a Lead-acid Cell – Curves of a Lead-acid Cell – Indications of a Fully Charged
    Lead-acid Cell – Load Characteristics of a Lead-acid Cell – Sulphation of Plates – Methods
    of Charging Batteries – Important Points About Charging of Lead-Acid Batteries – Effects of
    Overcharging – Care of Lead-acid Batteries – Applications of Lead-acid Batteries – Voltage
    Control Methods – Alkaline Batteries – Nickel-Iron Cell or Edison Cell – Electrical Characteristics
    of Nickel-Iron Cell – Nickel-Cadmium Cell – Comparison of Lead-acid Cell and Edison Cell –
    Silver-Zinc Batteries – Solar Cells – Fuel Cells – Objective Questions.
11. A.C. Fundamentals 521 – 577
    Alternating Voltage and Current – Sinusoidal Alternating Voltage and Current – Why Sine
    Waveform? – Generation of Alternating Voltages and Currents – Equation of Alternating
    Voltage and Current – Important A.C. Terminology – Important Relations – Different Forms
    of Alternating Voltage – Values of Alternating Voltage and Current – Peak Value – Average
    Value – Average Value of Sinusoidal Current – R.M.S. or Effective Value – R.M.S. Value of
    Sinusoidal Current – Importance of R.M.S. Values – Form Factor and Peak Factor – Complex
    Waveforms – R.M.S. Value of a Complex Wave – Phase – Phase Difference – Representation
    of Alternating Voltages and Currents – Phasor Representation of Sinusoidal Quantities – Phasor
    Diagram of Sine Waves of Same Frequency – Addition of Alternating Quantities – Subtraction
    of Alternating Quantities – Phasor Diagrams Using R.M.S. Values – Instantaneous Power – A.C.
    Circuit Containing Resistance Only – A.C. Circuit Containing Pure Inductance Only – A.C.
    Circuit Containing Capacitance Only – Complex Waves and A.C. Circuit – Fundamental Power
    and Harmonic Power – Objective Questions.
12. Series A.C. Circuits 578 – 633
    R-L Series A.C. Circuit – Impedance Triangle – Apparent, True and Reactive Powers – Power
    Factor – Significance of Power Factor – Q-factor of a Coil – Power in an Iron-Cored Choking
    Coil – R-C Series A.C. Circuit – Equivalent Circuit for a Capacitor – R-L-C Series A.C.
    Circuit – Resonance in A.C. Circuits – Resonance in Series A.C. Circuit (Series Resonance) –
    Resonance Curve – Q-Factor of Series Resonant Circuit – Bandwidth of a Series Resonant
    Circuit – Expressions for Half-power Frequencies – To Prove : fr = f f 1 2 – Expressions for
    Bandwidth – Important Relations in R-L-C Series Circuit – Applications of Series Resonant
    Circuits – Decibels – Objective Questions.
13. Phasor Algebra 634 – 665
    Notation of Phasors on Rectangular Co-ordinate Axes – Significance of Operatorj – Mathematical
    Representation of Phasors – Conversion from One Form to the Other – Addition and Subtraction
    of Phasors – Conjugate of a Complex Number – Multiplication and Division of Phasors – Powers
    and Roots of Phasors – Applications of Phasor Algebra to A.C. Circuits – R-L Series A.C.
    Circuit – R-C Series A.C. Circuit – R-L-C Series A.C. Circuit – Power Determination Using
    Complex Notation – Power Determination by Conjugate Method – A.C. Voltage Divider –
    Objective Questions.
    (vii)14. Parallel A.C. Circuits 666 – 721
    Methods of Solving Parallel A.C. Circuits – By Phasor Diagram – By Phasor Algebra – Equivalent
    Impedance Method – Admittance (Y) – Importance of Admittance in Parallel A.C. Circuit
    Analysis – Admittance Triangle – Admittance Method for Parallel Circuit Solution – Application
    of Admittance Method – Some Cases of Parallel Connected Elements – Series-Parallel A.C.
    Circuits – Series-to-Parallel Conversion and Vice-Versa – Resonance in Parallel A.C. Circuits
    (Parallel Resonance) – Graphical Representation of Parallel Resonance – Q-factor of a Parallel
    Resonant Circuit – Bandwidth of Parallel Resonant Circuit – Key Points About Parallel
    Resonance – General Case for Parallel Resonance – Comparison of Series and Parallel Resonant
    Circuits – Objective Questions.
14. Polyphase Circuits 722 – 829
    Polyphase System – Reasons for the Use of 3-phase System – Elementary 3-Phase Alternator –
    Some Concepts in 3-Phase System – Interconnection of Three Phases – Star or Wye Connected
    System – Important 3-Phase Terminology – Voltages and Currents in Balanced Y-Connected
    Supply System – Checking Correct Connections for Y-connected Alternator – Delta (D) or Mesh
    Connected System – Correct and Incorrect D Connections of Alternator – Voltages and Currents
    in Balanced D Connected Supply System – Advantages of Star and Delta Connected Systems –
    Constancy of Total Power in Balanced 3-phase System – Effects of Phase Sequence – Phase
    Sequence Indicator – Y/D or D/Y Conversions for Balanced Loads – 3-phase Balanced Loads
    in Parallel – Use of Single-Phase Wattmeter – Power Measurement in 3-phase Circuits – ThreeWattmeter Method – Two-Wattmeter Method – Proof for Two-Wattmeter Method – Determination
    of P.F. of Load by Two-wattmeter Method (For balanced Y or D load only) – Effect of Load p.f.
    on Wattmeter Readings – Leading Power Factor – How to Apply p.f. Formula ? – One-Wattmeter
    Method–Balanced Load – Reactive Power with Two-Wattmeter Method – Reactive Power with
    One Wattmeter – Unbalanced 3-Phase Loads – Four-Wire Star-Connected Unbalanced Load –
    UnbalancedD-Connected Load – Unbalanced 3-Wire Star-Connected Load – Methods of Solving
    Unbalanced 3-wire Y load – Solving Unbalanced 3-Wire Y Load by Kirchhoff’s Laws – Solving
    Unbalanced 3-wire Y Load By Loop Current Method – Solving Unbalanced 3-Wire Y Load by
    Y/D Conversion – Solving Unbalanced 3-Wire Y Load by Millman’s Theorem – Significance
    of Power Factor – Disadvantages of Low Power Factor – Causes of Low Power Factor – Power
    Factor Improvement – Power Factor Improvement Equipment – Calculations of Power Factor
    Correction – Objective Questions.
15. Electrical Instruments and Electrical Measurements 830 – 935
    Classification of Electrical Measuring Instruments – Types of Secondary Instruments – Principles
    of Operation of Electrical Instruments – Essentials of Indicating Instruments – Deflecting
    Torque – Controlling Torque – Damping Torque – Ammeters and Voltmeters – Permanent-Magnet
    Moving Coil (PMMC) Instruments (Ammeters and Voltmeters) – Extension of Range of PMMC
    Instruments – Extension of Range of PMMC Ammeter – Extension of Range of PMMC Voltmeter –
    Voltmeter Sensitivity – Dynamometer Type Instruments (Ammeters and Voltmeters) – Deflectiing
    Torque (Td) of Dynamometer Type Instruments in Terms of Mutual Inductance – Range Extension
    of Dynamometer Type Instruments – Moving-Iron (M.I.) Ammeters and Voltmeters – Attraction
    Type M.I. Instruments – Repulsion Type M.I. Instruments – Td of M.I. Instruments in Terms of
    Self-Inductance – Sources of Errors in Moving Iron Instruments – Characteristics of MovingIron Instruments – Extending Range of Moving-Iron Instruments – Comparison of Moving
    Coil, Dynamometer type and Moving Iron Voltmeters and Ammeters – Hot-Wire Ammeters
    and Voltmeters – Thermocouple Instruments – Electrostatic Voltmeters – Attracted Disc Type
    Voltmeter – Quadrant Type Voltmeter – Multicellular Electrostatic Voltmeter – Characteristics
    of Electrostatic Voltmeters – Range Extension of Electrostatic Voltmeters – Induction Type
    Instruments – Induction Ammeters and Voltmeters – Characteristics of Induction Ammeters
    and Voltmeters – Wattmeters – Dynamometer Wattmeter – Characteristics of Dynamometer
    Wattmeters – Wattmeter Errors – Induction Wattmeters – Three-phase Wattmeter – Watthour
    (viii)Meters or Energy Meters – Commutator Motor Meter – Mercury Motor Watthour Meter –
    Induction Watthour Meters or Energy Meters – Single-Phase Induction Watthour Meters or
    Energy Meters – Errors in Induction Watthour Meters – Three-Phase Watthour Meter – D.C.
    Potentiometer – Direct Reading Potentiometers – Modern D.C. Potentiometers – Crompton D.C.
    Potentiometers – Volt Ratio Box – Applications of D.C. Potentiometers – A.C. Potentiometer –
    Drysdale A.C. Potentiometer – Ballistic Galvanometer – Vibration Galvanometer – Frequency
    Meters – Vibrating-Reed Frequency meter – Electrodynamic Frequency Meter – Moving-Iron
    Frequency Meter – Power Factor Meters – Single-Phase Electrodynamic Power Factor Meter – 3-
    Phase Electrodynamic Power Factor Meter – Moving-Iron Power Factor Meter – 3-Voltmeter
    Method of Determining Phase Angle – Ohmmeter – Megger – Instrument Transformers – Current
    Transformer (C.T.) – Potential Transformer (P.T.) – Advantages of Instrument Transformers –
    Objective Questions.
16. A.C. Network Analysis 936 – 983
    A.C. Network Analysis – Kirchhoff’s Laws for A.C. Circuits – A.C. Mesh Current Analysis – A.C.
    Nodal Analysis – Superposition Theorem for A.C. Circuits – Thevenin’s Theorem for A.C.
    Circuits – Norton’s Theorem for A.C. Circuits – Thevenin and Norton Equivalent Circuits –
    Millman’s Theorem for A.C. Circuits – Reciprocity Theorem – Maximum Power Transfer Theorem
    for A.C. Circuits – A.C. Network Transformations – Objective Questions.
    Index 985 – 989
    A
    Absolute permeability, 355
    Absolute permittivity, 263
    Absolute potential, 278
    Admittance, 669
    Air dielectric capacitor, 304
    Air gap, 390
    Alternating current, 521

• average value, 532
• effective value, 535
• peak value, 532
• voltage, 521
  Ampere, 381
• turns, 386
  Angular velocity, 527
  Apparent Power, 581
  Atom, 2
  Average Power (a.c.) :
• in pure resistance, 565
• in pure inductance, 569
• in pure capacitance, 573
• in R-L series circuit, 579
• in R-C series circuit, 597
• in R-L-C series circuit, 606
• three phase circuit, 731
  B
  Balanced three phase, 728
  Bandwidth :
• series resonant circuit, 617
  Battery (Lead-Acid), 492
• care, 509
• charging, 504
• chemical action, 492
• construction, 496
• resistance, 498
• sulphation, 503
  B–H curve, 404
  Bridge :
• Wheatstone, 62
  C
  Calorie, 242
  Capacitance :
• in d.c. circuit, 296
• in a.c. circuit, 571
• parallel plate, 301
  Capacitive reactance, 572
  Capacitor, 295
• dielectric materials, 285
• in parallel, 320
• in series, 319
  Cell, 491
• alkaline, 512
• lead-acid, 492
• nickel-cadmium, 514
• solar, 516
  Charge, 1
  Circuit :
• d.c. series, 36
• d.c. parallel, 39
• d.c. series-parallel, 48
• a.c. series, 578
• a.c. parallel, 666
• polyphase, 722 – 829
  Co-efficient :
• of coupling, 447
• temperature, 18
  Compass, 352
  Conductance, 669
  Conventional current, 4
  Cost of energy, 30
  Coulomb, 1
  985
  Index986 Basic Electrical Engineering
  Coulomb’s Laws, 350
  Complex Numbers, 634 – 665
• addition and subtraction, 639
• conjugate, 641
• multiplication and division, 641
• polar form, 637
  Current :
• alternating, 521
• conventional, 4
• direct, 4
• electron, 1
  Cutting of flux, 431
  Cycle, alternating current, 526
  D
  Decaying – R-L circuit, 471
  Delta connection, 740
  Delta-Wye transformation, 216
  Dielectric :
• constant, 297
• strength, 285
  Discharging :
• battery, 492
• capacitor, 338
  E
  Eddy current loss, 476
  Effective value :
• sinusoidal, 535
  Electric field, 268
• intensity, 269
• energy stored, 328
  Electric force between :
• parallel plates, 332
  Electric Potential, 7
• difference, 8
  Electromagnetic force between :
• current carrying conductors, 380
• Current carrying conductor in magnetic
  field, 364
  Electromagnetic induction, 430
• Faraday’s laws, 431
  Electromotive force, 431
  Electrons :
• valence, 2
• free, 2
• theory, 1
  Energy :
• electrical, 241
• thermal, 242
• stored in electric field, 328
• stored in magnetic field, 459
  F
  Farad, 297
  Faraday’s laws :
• electromagnetic induction, 431
  Field :
• electric, 268
• magnetic, 352
  Field intensity :
• electric, 269
• magnetic, 355
  Figure of merit (Q), 583
  Fleming’s rule :
• left-hand, 365
• right-hand, 433
  Form factor, 538
  Flux :
• electric, 273
• magnetic, 352
• leakage (magnetic), 391
• linkages, 431
  Flux-density :
• electric, 273
• magnetic, 353
  Free electrons, 2
  Free space :
• permeability, 355
• permittivity, 263
  Frequency, 527Index 987
  G
  Generator :
• elementary a.c., 523
  Graphical representation of :
• temperature co-efficient, 18
  H
  Henry, 440
  Horse power, 243
  Hydrometer, 502
  Hysteresis :
• phenomenon, 417
• loss, 419
  I
  Impedance, 579
• triangle, 580
  Inductance :
• self, 439
• mutual, 445
  Instruments :
• controlling torque, 832
• damping torque, 836
• deflecting torque, 832
• dynamometer type instruments, 851
• electrostatic voltmeters, 871
• frequency meter, 919
• hot-wire instruments, 867
• induction type instruments, 878
• induction wattmeters, 893
• induction watthour meter, 902
• moving-iron instruments, 857
• permanent magnet moving-coil instruments, 838
• power factor meter, 923
• wattmeters, 882
  Internal resistance :
• battery, 498
• supply, 49
  K
  Kilovolt-ampere, 581
  Kilowatt-hour, 30
  Kirchhoff’s laws :
• current, 65
• voltage, 66
  L
  Laminations, 476
  Leakage flux, 391
  Lenz’s law, 432
  Line voltage, 730
  Lines of force :
• electric, 269
• magnetic, 352
  Loads :
• balanced Y, 728
• balanced ∆, 728
• unbalanced 4-wire Y, 787
  Losses :
• eddy currents, 476
  M
  Magnetic circuits, 386
• series, 389
• parallel, 390
  Magnetic :
• attraction, 350
• field, 352
• materials, 360
• reluctance, 387
  Magnetism :
• molecular theory, 358
• residual, 418
  Magnetic fields :
• long straight conductors, 361
• parallel conductors, 361
• solenoid, 362
  Magnetisation curves, 404
  Magneto-motive force, 387988 Basic Electrical Engineering
  Maximum power transfer, 198
  Microfarad, 297
  Millman’s theorem, 209
  N
  Negative temperature co-efficient, 18
  Network theorems, 106 – 238
  Newton, 240
  Neutral current, 731
  Neutral point, 727
  Neutral wire, 727
  Nickel-iron cell, 512
  Nickel-cadmium cell, 514
  Norton’s theorem, 179
  Notation :
• double subscript, 726
• symbolic, 636
  Numbers, complex, 634 – 655
  Nucleus, 1
  O
  Oersted, 360
  Ohm, 10
  Ohm’s law, 27
  P
  Parallel circuits :
• a.c., 666 – 721
• capacitors, 320
• d.c., 39
• magnetic, 390
• resistance, 39
  Parallel-plate capacitors, 301
  Peak factor, 539
  Peak value, 532
  peak, a.c., 532
  Permittivity, 263
  Phase, 555
• difference, 555
  Phasor, 556
  Phase sequence, 725
  Phase voltage, 727
  Pico-farad, 297
  Poles, 350
  Polyphase circuits, 722
  Potential, 7
  Potential difference, 8
  Power :
• active, 581
• apparent, 581
• reactive, 582
• three phase, 731, 743
  Power factor, 583
• improvement, 817
• significance, 815
  Power transfer theorem, 198
  Primary cell, 491
  Product-over sum rule :
• capacitors in series, 319
• resistors in parallel, 41
  Protons, 1
  Q
  Quality factor (Q) :
• parallel circuits, 707
• series circuits, 617
  Quadrature component, 635
  R
  Reactance :
• capacitive, 572
• inductive, 569
  Reactive volt-ampere, 582
  Real component, 635
  Reciprocity theorem, 207
  Relative permeability, 355
  Reluctance, 387
  Residual, 418
  Resistance, 10
• combination in series, 36
• parallel combinations, 39
• temperature co-efficient, 18
• variation with temperature, 18Index 989
  Resistivity, 11
  Right-hand rule, 360
  Root mean square value, 535
• mathematical determination, 537
  S
  Secondary cells, 491
• charging method, 504
  Self-induced voltage, 438
  Self-inductance, 439
• factors affecting, 440
  Series circuits :
• d.c., 36
• a.c., 578 – 633
  Series-parallel circuit, d.c., 48
  Sine curve, 522
  Sinusoidal waveform, 522
  Solar cell, 516
  Star connection, 727
  Storage cells, 491
• Edison type, 512
• lead-acid, 492
• nickel-cadmium, 514
  Superposition theorem, 133
  Susceptance, 669
  Symbolic notation, 636
  System of units, S.I., 239
  T
  Temperature co-efficient of resistance, 18
  Test charge, 278
  Theorems (a.c.) :
• max. power transfer, 973
• Millman’s, 969
• Notron’s, 964
• superposition, 950
• Thevenin’s, 955
  Theorems (d.c.) :
• max. power transfer, 198
• Millman’s, 209
• Norton’s, 179
• reciprocity, 207
• superposition, 133
• Thevenin’s, 150
  Three phase circuits, 722 – 829
• delta connection, 740
• power, 731, 743
• star connection, 727
  Thumb rule, 505
  Time period, a.c., 526
  Triangle impedance, 580
  Trigonometrical form, 636
  Two-wattmeter method, 765
  U
  Unbalanced load, 786
  Unit magnetic pole, 351
  Units :
• energy, 240
• power, 242
• thermal, 242
• work, 240
  V
  Var, 582
  Voltage, 8
  Volt-ampere, 581
  Voltage law (Kirchhoff), 66
  W
  Wattless component, 582
  Watt, 30
• component, 582
• hour, 30
• second, 30
  Weber, 351
  Wheatstone bridge, 62
  Work, 240
  Wye load, 728
  Y
  Y-load, 728
  Y-∆ transformation, 217

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