Wiley Acing the Gate: Electrical Engineering

Preface v
About the Authors vii
Acing the GATE ix
Syllabus for Electrical Engineering (EE) xv
SECTIONS I & II: ELECTRIC CIRCUITS AND ELECTROMAGNETIC FIELDS 1
1 Electric Circuits 3
1.1 Circuit Concepts and Laws 3
1.1.1 Electrical Quantities and Units 4
1.1.2 Types of Circuits 7
1.1.3 Current and Voltage Sources 9
1.1.4 Kirchoff’s Laws 12
1.2 Circuit Analysis Techniques 14
1.2.1 Equivalent Circuits 14
1.2.2 Series and Parallel Networks for Resistors, Capacitors and Inductors 15
1.2.3 Source Transformation 17
1.2.4 Nodal and Mesh Analysis 18
1.3 Topology 21
1.3.1 Graph of a Network 21
1.3.2 Directed and Undirected Graph 22
1.3.3 Planar and Non-Planar Graph 22
1.3.4 Concept of Tree and Co-Tree 22
xviii  CONTENTS
1.3.5 Incidence Matrix 23
1.3.6 Link Currents: Tie Set Schedules 24
1.3.7 Cut Set and Tree Branch Voltages 25
1.3.8 Interelation between Matrices 27
1.3.9 Summarised Properties 27
1.4 Network Theorems 27
1.4.1 Linearity and Superposition 27
1.4.2 Superposition Theorem 27
1.4.3 Thevenin’s Theorem 28
1.4.4 Norton’s Theorem 31
1.4.5 Maximum Power Transfer Theorem 33
1.4.6 Reciprocity Theorem 35
1.4.7 Substitution Theorem 37
1.4.8 Tellengen’s Theorem 37
1.4.9 Compensation Theorem 39
1.4.10 Millman’s Theorem 39
1.4.11 Duality Theorem 40
1.4.12 Wye(Star)-Delta Transformations 40
1.5 Laplace Transform 43
1.5.1 Properties of Laplace Transform 43
1.5.2 Laplace Transform of Periodic Function 44
1.6 Transient Response To DC and AC Networks 45
1.6.1 Initial and Steady State 46
1.6.2 DC Transients 47
1.6.3 AC Transients 57
1.7 Sinusoidal Steady State Analyses Using Phasors 62
1.7.1 Phasor 63
1.7.2 Phasor Relationship for Circuit Elements 64
1.8 Magnetically Coupled Circuits 70
1.8.1 DOT Convention 70
1.8.2 Series Connection of Coupled Inductors 70
1.8.3 Parallel Connection of Coupled Coils 71
1.8.4 Analysis of Multiwinding Coupled Circuits 71
1.8.5 Ideal Transformer 73
1.9 Resonance 73
1.9.1 Series Resonance 73
1.9.2 Parallel Resonance 75
1.10 Filters 77
1.11 Three-Phase Circuits 79
1.11.1 Balanced Three-Phase Circuits 80
1.11.2 Unbalanced Three-Phase Circuits 81
1.12 AC Power Analysis 81
1.12.1 Sinusoidal Signals 81
1.12.2 Average Power 81
1.12.3 Effective (RMS) Values of Current and Voltage 82
1.13 Two-Port Network 83
1.13.1 Types of Network Parameters 84
1.13.2 Interconnections of Two-Port Network 87
CONTENTS xix
Important Formulas 89
Solved Examples 95
Practice Exercises 112
Answers to Practice Exercises 124
Solved Gate Previous Years’ Questions 142
2 Electromagnetic Fields 169
2.1 Coulomb’s Law 169
2.2 Electric Field Intensity 169
2.3 Electric Flux Density 170
2.3.1 Relation between Electric Flux Density and Electric Field Intensity 170
2.4 Divergence and Curl 170
2.4.1 Divergence 170
2.4.2 Curl 170
2.5 Divergence and Stokes’ Theorems 171
2.6 Gauss’s Law 171
2.7 Electric Field and Potential 171
2.7.1 Due to Point Charge 171
2.7.2 Due to Line Charge 172
2.7.3 Due to a Plane (or Infinite Sheet) of Charge 172
2.7.4 Due to Uniformly Charged Sphere 172
2.7.5 Due to Different Distributions 173
2.7.6 Effect of Dielectric Medium on Electric Field 173
2.8 Capacitance 173
2.8.1 Expression for a Parallel Plate Capacitor 173
2.8.2 Series and Parallel Combination of Capacitors 173
2.9 Magnetic Flux and Magnetic Field 174
2.10 Biot—Savart Law 174
2.11 Ampere’s Law 174
2.12 Faraday’s Law and Lenz’s Law of Electromagnetic Induction 174
2.12.1 Faraday’s First Law 174
2.12.2 Faraday’s Second Law 174
2.12.3 Derivation of Faraday’s Law 175
2.12.4 Lenz’s Law 175
2.13 Lorentz Force 175
2.14 Maxwell’s Equations 175
2.14.1 Magnetic Boundary Conditions 175
2.15 Poynting Vector 175
2.16 Inductance 175
2.16.1 Series and Parallel Combination of Inductors 176
2.16.2 Self Inductance 176
2.16.3 Mutual Inductance 176
2.17 Self and Mutual Inductance for Simple Configurations 177
2.17.1 Inductance of Solenoid 177
2.17.2 Inductance of a Coaxial Cable 178
2.18 Magnetic Circuit and Magnetomotive Force 179
2.18.1 Reluctance 179
xx  CONTENTS
Important Formulas 179
Solved Examples 181
Practice Exercises 182
Answers to Practice Exercises 183
Solved Gate Previous Years’ Questions 184
SECTION III: SIGNALS AND SYSTEMS 189
3 Signals and Systems 191
3.1 Elementary Signals 191
3.1.1 Basic Operations of Independent Variables 195
3.2 Classification of Signals 196
3.3 System 198
3.3.1 Continuous-Time and Discrete-Time Systems 198
3.3.2 Time Invariant and Time Variant Systems 198
3.3.3 Linear and Non-Linear Systems 199
3.3.4 Causal and Non-Causal Systems 199
3.3.5 Stable and Unstable Systems 200
3.3.6 Invertible and Non-Invertible Systems 200
3.3.7 Static and Dynamic Systems 200
3.4 Time Domain Representation of Linear Time Invariant System 200
3.4.1 Convolution 201
3.4.2 Differential Equation Representation of LTI System 202
3.4.3 Difference Equation Representation of LTI System 202
3.4.4 Linear Time Invariant System with Random Input 203
3.4.5 Types of LTI Systems 203
3.5 Continuous-Time Fourier Series 204
3.5.1 Coefficient Values of Fourier Series 204
3.5.2 Exponential Form of Fourier Series 205
3.6 Discrete-Time Fourier Series 207
3.6.1 Power Density Spectrum of Periodic Signal 208
3.7 Continuous-Time Fourier Transform 209
3.7.1 Properties of Continuous-Time Fourier Transform 211
3.8 Discrete-Time Fourier Transform 216
3.8.1 Properties of Discrete-Time Fourier Transform 216
3.9 Discrete Fourier Transform
(DFT) and Fast Fourier Transform
(FFT) 221
3.9.1 Discrete Fourier Transform (DFT) 221
3.9.2 Fast Fourier Transform (FFT) 222
3.10 Sampling Theorem for Continuous-Time Signal 222
3.10.1 Impulse Train Sampling of a Continuous-Time Signal 222
3.10.2 Zero-Order Hold Sampling 223
3.11 Laplace Transform 223
3.11.1 Inverse Laplace Transform 224
3.11.2 Properties of Laplace Transform 224
3.12 Z-Transform and its Application to the Analysis of LTI System 229
3.12.1 Region of Convergence 229
3.12.2 Properties of Z-Transform 229
CONTENTS xxi
3.12.3 Inverse Z-Transform 235
3.13 Realisable LTI Systems 237
Important Formulas 239
Solved Examples 243
Practice Exercises 246
Answers to Practice Exercises 249
Solved Gate Previous Years’ Questions 252
SECTION IV: ELECTRICAL MACHINES 267
4 Electrical Machines 269
4.1 Transformer 269
4.1.1 Ideal Transformer 270
4.1.2 Three-Phase Transformer 277
4.1.3 Parallel Operations of Transformers 280
4.1.4 Per Unit System 280
4.2 DC Machines 281
4.2.1 Commutation 282
4.2.2 EMF Induction 282
4.2.3 Type of Connections 283
4.2.4 DC Generator Characteristics 284
4.2.5 Parallel Operations of DC Generators 285
4.2.6 DC Motors 286
4.2.7 Power Stages in DC Generator and Motor 290
4.2.8 Testing of DC Machines 290
4.2.9 Electrical Braking 291
4.3 Three Phase Induction Machines 291
4.3.1 Rotating Magnetic Field 292
4.3.2 Equivalent Circuit 293
4.3.3 Determination of Circuit Parameters 294
4.3.4 Power Flow Diagram of Induction Machine 295
4.3.5 Complete Torque−Speed Characteristics 295
4.3.6 Methods of Starting Three-Phase Induction Motors 297
4.4 Single-Phase Induction Motor 298
4.4.1 Double-Field Revolving Theory 298
4.4.2 Equivalent Circuit of Single Phase Induction Machine 298
4.4.3 Starting Methods for Single Phase Induction Motor 299
4.4.4 Shaded-Pole Motors 301
4.5 Synchronous Machines 302
4.5.1 Principle of Operation 303
4.5.2 Phasor Diagram 303
4.5.3 Open-Circuit and Short-Circuit Tests 303
4.5.4 Zero Power Characteristics and Potier Triangle 304
4.5.5 Generator Voltage Regulation 305
4.5.6 Two Reaction Theory of Salient-Pole Machines (Blondel’s Two-Reaction Theory) 305
4.5.7 Synchronous Motor Power Equation 306
4.5.8 Power Angle Characteristics 306
xxii  CONTENTS
4.5.9 Synchronizing Power and Synchronizing Torque 307
4.5.10 Power Factor Control 307
4.5.11 Hunting 307
4.5.12 Slip Test 308
4.5.13 Cogging and Crawling 308
4.5.14 Comparison between Synchronous Motors and Induction Motors 308
4.6 Stepper and Servo Motors 309
4.6.1 Stepper Motor 309
4.6.2 Servo Motors 310
Important Formulas 311
Solved Examples 314
Practice Exercises 326
Answers to Practice Exercises 333
Solved Gate Previous Years’ Questions 338
SECTION V: POWER SYSTEMS 369
5 Power Systems 371
5.1 Power Generation Concepts 371
5.1.1 Some Standard Terms used in Power Systems 372
5.2 Transmission Line Parameters 372
5.2.1 Inductance 372
5.2.2 Capacitance 373
5.2.3 Resistance 374
5.3 Transmission Lines 375
5.3.1 Transmission Line Performance 375
5.3.2 Classification of Transmission Line 375
5.3.3 Combination of Networks 378
5.3.4 Ferranti Effect 379
5.3.5 Surge Impedance 379
5.4 AC and DC Transmission Concepts 379
5.4.1 Comparison of AC and DC Transmission 379
5.5 Insulated Cables 381
5.5.1 Construction of Cables 381
5.5.2 Classification of Cables 382
5.5.3 Dielectric Stress in Cables 382
5.5.4 Most Economical Size of Conductor 382
5.5.5 Grading of Cables 383
5.6 Electric Line Insulators 384
5.6.1 Electrical Stresses on External Insulation 385
5.6.2 Types of Insulators 385
5.6.3 Voltage Distribution in Suspension Insulator 385
5.6.4 Electric Field Distribution 386
5.7 Distribution Systems 387
5.7.1 Classification of Distribution Systems 387
5.7.2 AC and DC Distribution Systems 387
5.7.3 Connection Schemes 388
CONTENTS xxiii
5.8 PU (Per Unit System) 389
5.9 Bus Admittance Matrix 389
5.9.1 Gauss—Seidel Method of Load Flow Analysis 389
5.9.2 Newton—Raphson Method for Load Flow Analysis 390
5.10 Voltage Control 391
5.10.1 Voltage Control by Reactive Power Injection 391
5.10.2 Voltage Control using Tap Changing Transformers 393
5.10.3 Voltage Control by Combination of Tap Changing Transformer and Reactive
Power Injection 393
5.11 Frequency Control 394
5.12 Power System Stability Concepts 394
5.12.1 Power-Angle Characteristics 394
5.12.2 Swing Equation 394
5.12.3 Equal-Area Criterion 395
5.13 Power Factor Correction 399
5.13.1 Power Factor Correction Formula 400
5.14 Symmetrical Components 400
5.14.1 Symmetrical Components Transformation 400
5.15 Faults 401
5.15.1 Unsymmetrical Fault Analysis 401
5.15.2 Symmetrical Fault Analysis 404
5.15.3 Open Conductor Faults 406
5.16 Relays 408
5.17 Protection 409
5.17.1 Overcurrent Protection 409
5.17.2 Distance Protection 410
5.17.3 Differential Protection 411
5.18 Circuit Breakers 411
5.18.1 Arc Phenomenon 412
5.19 High Voltage Direct Current Transmission 412
5.19.1 Comparison of HVAC and HVDC 413
5.19.2 Corona 413
5.20 Economics of Power Generation 414
Important Formulas 414
Solved Examples 419
Practice Exercises 434
Answers to Practice Exercises 441
Solved Gate Previous Years’ Questions 448
SECTION VI: CONTROL SYSTEMS 485
6 Control Systems 487
6.1 Fundamentals 487
6.1.1 Reasons for Building Control Systems 488
6.1.2 Classification of System 489
6.1.3 Modeling of Physical Systems 491
6.1.4 Effects of Negative Feedback 495
xxiv  CONTENTS
6.1.5 Sensitivity of Control Systems 495
6.1.6 Model Simplifications using Block Diagram Algebra 496
6.1.7 Signal-Flow Graphs 498
6.2 Time-Response Analysis 499
6.2.1 Transient State Behaviour 499
6.2.2 Steady-State Behaviour 501
6.2.3 Transient Response of Second-Order Systems 504
6.2.4 Nature of System Response vs. Location of Closed-Loop Poles 505
6.3 Stability of Control Systems 507
6.3.1 Bounded Input Bounded Output Stability 507
6.3.2 Routh−Hurwitz (RH) Stability Criterion 507
6.4 Root Locus Technique 509
6.4.1 Concepts of Root Locus − Intuitive Example 509
6.4.2 Rules of Sketching Root Locus 510
6.4.3 Systems with Time Delay 513
6.4.4 Root Locus for System with Gain −K 514
6.5 Frequency Response Analysis 514
6.5.1 Polar Plots 515
6.5.2 Closed-Loop Poles and Zeros of a Negative Feedback System 516
6.5.3 Principle of Argument 516
6.5.4 Nyquist Contour 517
6.5.5 Nyquist Stability Criterion 519
6.6 Bode Plots 520
6.6.1 Advantages of Bode Plots 520
6.6.2 Measures of System Performance in Frequency Domain 523
6.7 Compensators 525
6.7.1 Proportional (P) Control 525
6.7.2 Integral (I) Control 526
6.7.3 Proportional plus Integral (PI) Control 527
6.7.4 Proportional plus Derivative (PD) Control 527
6.7.5 Proportional Integral Derivative (PID) Control 527
6.7.6 Lead Compensator 528
6.7.7 Phase Lag Compensator 529
6.7.8 Realisation using Op-amps 530
6.8 State Space Representation 531
6.8.1 Concept of State 531
6.8.2 Transforming Differential Equation Representation into State Space Representation 532
6.8.3 Time Response from State Representation 533
6.8.4 Obtaining Transfer Function Representation from State Space Representation 533
6.8.5 State Transition Matrix 533
6.8.6 Similarity Transformations 533
6.8.7 Canonical Forms 533
Important Formulas 535
Solved Examples 538
Practice Exercises 552
Answers to Practice Exercises 565
Solved Gate Previous Years’ Questions 576
CONTENTS xxv
SECTION VII: ELECTRICAL AND ELECTRONIC MEASUREMENTS 613
7 Electrical and Electronic Measurements 615
7.1 Classification of Measuring Instruments 615
7.1.1 Indicating Type Instruments 616
7.2 Types of Indicating Instruments 616
7.2.1 Permanent Magnet Moving Coil Instruments 617
7.2.2 Moving Iron Type Instruments 618
7.2.3 Electrodynamic Type Meters 618
7.2.4 Measurement of High-Frequency Signals 619
7.3 Bridges and Potentiometers 619
7.3.1 Measurement of Inductance 620
7.3.2 Measurement of Capacitance 623
7.3.3 Measurement of Mutual Inductance 625
7.3.4 Measurement of Resistance 626
7.4 Measurement of Current and Voltage 630
7.4.1 Shunts and Multipliers 630
7.4.2 Sensitivity of Ammeter and Voltmeter 631
7.5 Measurement of Power and Energy 631
7.5.1 Measurement of Power in AC Circuits 631
7.5.2 Measurement of Power in a Three-Phase Circuit 633
7.6 Instrument Transformers 636
7.6.1 Current Transformer 636
7.6.2 Voltage Transformer 637
7.6.3 Linear Variable Differential Transformer (LVDT) 638
7.6.4 Errors in Instrument Transformers 638
7.7 Digital Voltmeters and Multimeters 639
7.8 Cathode Ray Oscilloscope 639
7.8.1 Working of CRO 640
7.8.2 CRO Controls 641
7.8.3 Measurements of Voltage 641
7.8.4 Measurement of Frequency 642
7.8.5 Measurement of Phase Difference 643
7.9 Q-Meter 643
7.10 Transducers 644
7.10.1 Strain Gauge 644
7.10.2 Velocity Transducers 644
7.10.3 Temperature Sensing Devices 645
7.10.4 Transducers for Fluid Flow Measurement 645
7.10.5 Capacitive Transducer 646
7.10.6 Piezo-Electric Transducer 646
7.10.7 Bourdon Tube 647
7.10.8 Bellows 647
7.11 Error Analysis 647
7.11.1 Types of Errors 647
7.11.2 Mean Value and Deviation 648
7.11.3 Precision and Calibration 648
xxvi  CONTENTS
Important Formulas 648
Solved Examples 651
Practice Exercises 658
Answers to Practice Exercises 663
Solved Gate Previous Years’ Questions 668
SECTION VIIIA: ANALOG ELECTRONICS 685
8 Analog Electronics 687
8.1 Semiconductor Physics 687
8.1.1 Insulators, Semiconductors and Metals 687
8.1.2 Types of Semiconductors 688
8.1.3 Donor and Acceptor Impurities 688
8.1.4 Drift and Diffusion Currents 689
8.1.5 Mass Action Law 690
8.1.6 Energy Band Gap 691
8.1.7 Mobility 692
8.1.8 Hall Effect 692
8.2 Semiconductor Diodes 693
8.2.1 The Equilibrium p-n Junction Diode 693
8.2.2 Operational Characteristics 694
8.2.3 Voltage-Current (V-I ) Characteristics of a Diode 696
8.2.4 Diode Resistance 697
8.2.5 Diode Junction Capacitance 698
8.2.6 Diode Equivalent Circuits 700
8.2.7 Breakdown Diodes 701
8.3 Transistors 702
8.3.1 Bipolar Junction Transistor 703
8.3.2 Load Line and Modes of Operation 703
8.3.3 Transistor Configurations 705
8.3.4 Transistor as Amplifier 713
8.4 Field-Effect Transistor (JFET and MOSFET) 715
8.4.1 Junction Field Effect Transistors 715
8.4.2 MOSFETS 720
8.5 Simple Diode Circuits 729
8.5.1 Connecting Diodes in Series and Parallel 729
8.5.2 Clippers 730
8.5.3 Clampers 732
8.5.4 Rectifier Circuits 735
8.5.5 Voltage Regulator 741
8.6 Stability and Biasing 743
8.6.1 Stabilisation 743
8.6.2 Transistor (BJT) Biasing 744
8.6.3 Compensation Techniques (Bias Compensation) 747
8.6.4 Bias Stabilisation in FET (JFET and MOSFET) 748
8.7 Amplifiers 751
8.7.1 Single Stage Amplifiers 751
CONTENTS xxvii
8.7.2 Hybrid Equivalent Model 754
8.7.3 Multistage Amplifiers 757
8.7.4 Differential Amplifier 760
8.7.5 Operational Amplifier 763
8.7.6 Feedback Amplifier 768
8.7.7 Power Amplifiers 768
8.8 Frequency Response 775
8.8.1 Low Frequency Response — BJT Amplifier 776
8.8.2 Low Frequency Response — FET Amplifier 777
8.8.3 Miller Effect Capacitance 777
8.8.4 High Frequency Response — BJT Amplifier 779
8.8.5 High Frequency Response — FET Amplifier 780
8.8.6 Multistage Frequency Effects 780
8.9 Active Filters 781
8.9.1 First-Order Low-Pass Butterworth Filter 781
8.9.2 Second-Order Low-Pass Butterworth Filter 781
8.9.3 First-Order High-Pass Butterworth Filter 782
8.9.4 Second-Order High-Pass Butterworth Filter 782
8.9.5 Band-Pass Filters 783
8.9.6 Band-Stop Filter 783
8.9.7 All-Pass Filter 784
8.10 Oscillators 785
8.10.1 Types of Oscillators 785
8.10.2 Sinusoidal Oscillator 785
8.11 Multivibrators 787
8.11.1 Astable or Free Running Multivibrator 787
8.11.2 Monostable Multivibrator 788
8.11.3 Bistable Multivibrator 789
8.11.4 Schmitt Trigger 790
8.11.5 IC-555 Timer 791
8.12 Sample and Hold Circuits 792
Important Formulas 793
Solved Examples 801
Practice Exercises 824
Answers to Practice Exercises 837
Solved Gate Previous Years’ Questions 847
SECTION VIIIB: DIGITAL ELECTRONICS 877
9 Digital Electronics 879
9.1 Number Systems 879
9.1.1 Types of Number Systems 879
9.1.2 Number Conversions 880
9.1.3 Binary and Hexadecimal Arithmetic 882
9.1.4 Fixed Precision and Overflow 882
9.1.5 Representation of Binary Numbers 883
9.1.6 Binary Codes 885
xxviii  CONTENTS
9.2 Boolean Algebra 887
9.2.1 Boolean Function 887
9.2.2 Laws of Boolean Algebra 888
9.2.3 Simplification of Boolean Function 889
9.3 Logic Gates 893
9.3.1 Universal Gates 893
9.4 Logic Families 895
9.4.1 Characteristic Parameters 895
9.4.2 Resistor-Transistor Logic (RTL) 896
9.4.3 Diode-Transistor Logic (DTL) 897
9.4.4 Transistor-Transistor Logic (TTL) 897
9.4.5 Emitter Coupled Logic (ECL) Family 899
9.4.6 CMOS Logic Family 900
9.5 Combinational Logic Circuits 901
9.5.1 Arithmetic Combinational Circuits 901
9.5.2 Multiplexers 907
9.5.3 Demultiplexers 908
9.5.4 Decoders and Encoders 909
9.6 Memory 913
9.6.1 Classification of Memory 913
9.6.2 Read Only Memory (PROM) 913
9.7 Sequential Logic Circuits 913
9.7.1 Flip-Flops 914
9.7.2 Counters 920
9.7.3 Registers 923
9.8 D/A and A/D Converters 926
9.8.1 D/A Converters 926
9.8.2 A/D Converter 928
9.9 Microprocessors 930
9.9.1 Microprocessor Architecture 930
9.9.2 Basic Microprocessor Instructions 931
9.9.3 Assembly Language 934
9.10 8085 Microprocessors 934
9.10.1 Microprocessor Bus Architecture 936
9.10.2 Pin Diagram of 8085 Microprocessor 937
9.10.3 8085 Interrupt Structure 939
9.10.4 Addressing Modes in 8085 939
9.10.5 Machine Cycle 940
9.10.6 Execution of Program by Microprocessor 940
9.11 Memory Interfacing 942
9.11.1 Memory Structure 943
9.11.2 Address Decoding and Memory Mapping 943
Important Formulas 943
Solved Examples 946
Practice Exercises 953
Answers to Practice Exercises 959
Solved Gate Previous Years’ Questions 964
CONTENTS xxix
SECTION X: POWER ELECTRONICS 981
10 Power Electronics 983
10.1 Power Semiconductor Devices 983
10.1.1 Basic p-n Diode Characteristics 983
10.2 Bipolar Junction Transistor 985
10.2.1 Construction and Operating Principle of BJTs 985
10.2.2 Static Characteristics of BJTs 986
10.2.3 Conduction and Switching Losses of BJT 986
10.2.4 Paralleling of BJTs and Power Darlingtons 987
10.3 Thyristors 988
10.3.1 Construction and Operating Principle of Thyristors 988
10.3.2 Static Characteristics of a Thyristor 990
10.3.3 Thyristors Turn-ON Methods 991
10.3.4 Thyristor Protection 991
10.4 Triac 992
10.4.1 Construction and Operating Principle of Triac 992
10.4.2 Static Characteristics of Triac 993
10.5 Gate Turn-OFF Thyristor (GTO) 993
10.5.1 Construction and Operating Principle of GTO 994
10.6 Power Metal Oxide Semiconductor Field Effect Transistors (MOSFETS) 994
10.6.1 Construction and Operating Principle of Power MOSFETs 995
10.6.2 Static Characteristics of a Power MOSFET 996
10.7 Insulated Gate Bipolar Transistor (IGBT) 997
10.7.1 Construction and Operating Principle of IGBT 997
10.7.2 Static Characteristics of an IGBT 998
10.8 Performance Parameters 999
10.9 Converters: AC-DC Rectifiers 1000
10.9.1 Single-Phase Uncontrolled Half-Wave Rectifier 1000
10.9.2 Single-Phase Uncontrolled Full-Bridge Rectifier with RLE Load 1002
10.9.3 Single Phase Half-Wave Controlled Rectifier with Resistive Load 1003
10.9.4 Single-Phase Half-Wave Controlled Rectifier with Resistive-Inductive Load 1004
10.9.5 Single-Phase Half-Controlled Converter with RLE Load 1005
10.9.6 Single-Phase Fully-Controlled Bridge Converter with RLE Load 1007
10.9.7 Three-Phase Half-Wave Uncontrolled Rectifier 1008
10.9.8 Three Phase Full-Wave Uncontrolled Bridge Rectifier Feeding RLE Load 1009
10.9.9 Three-Phase Half-Controlled Converter Feeding RLE Load 1010
10.9.10 Three-Phase Fully-Controlled Bridge Converter Feeding RLE Load 1011
10.10 DC to DC Conversion 1012
10.10.1 Choppers 1012
10.10.2 Types of DC to DC Converters 1015
10.10.3 Buck or Step-Down Converters 1015
10.10.4 Boost or Step-Up Converters 1015
10.10.5 Buck-Boost Converters 1016
10.11 DC Line Commutation 1017
10.11.1 Commutation with Parallel Capacitance Configuration 1017
10.11.2 Commutation by Another Load Carrying Thyristor 1018
xxx  CONTENTS
10.12 Inverters 1019
10.12.1 Voltage Source Inverters 1019
10.12.2 Current Source Inverters 1021
10.13 Pulse Width Modulation 1022
10.13.1 Sinusoidal Pulse Width Modulation 1022
10.14 Bidirectional AC to DC Voltage Source Converter 1023
10.15 Speed Control of DC Motor Drives 1023
10.15.1 Pulse Width Modulated Converter for DC Drive System 1024
10.15.2 Closed Loop Control of DC Motors 1025
10.16 Speed Control of AC Motor Drives 1026
10.16.1 Induction Motor Speed Control 1026
10.16.2 Closed Loop Constant Voltage/Constant Frequency Controller 1026
10.16.3 Pulse Width Modulated (PWM) Converter for AC Drive System 1027
Important Formulas 1027
Solved Examples 1032
Practice Exercises 1038
Answers to Practice Exercises 1044
Solved Gate Previous Years’ Questions 1048
Solved GATE 2014 1077
Solved GATE 2015 1129
Solved GATE 2016 1161
Index