Chapter 10. Basic Electricity
Basic Electricity 10-1
Basic Electricity 10-1
Introduction to Electricity and Electronics 10-1
General Composition of Matter 10-1
Matter 10-1
Element 10-1
Compound 10-1
The Molecule 10-1
The Atom 10-2
Electrons, Protons, and Neutrons 10-2
Electron Shells and Energy Levels 10-2
Valence Electrons 10-3
Ions 10-3
Free Electrons 10-3
Electron Movement 10-3
Conductors 10-3
Insulators 10-3
Semiconductors 10-3
Metric Based Prefixes Used for Electrical Calculations 10-3
Static Electricity 10-4
Attractive and Repulsive Forces 10-4
Electrostatic Field 10-5
ESD Considerations 10-6
Magnetism 10-7
Types of Magnets 10-11
Electromagnetism 10-12
Conventional Flow and Electron Flow 10-16
Conventional Flow 10-16
Electron Flow 10-16
Electromotive Force (Voltage) 10-16
Current 10-17
Ohm’s Law (Resistance) 10-17
Resistance of a Conductor 10-19
Factors Affecting Resistance 10-19
Resistance and Its Relation to Wire Sizing 10-20
Circular Conductors (Wires/Cables) 10-20
Rectangular Conductors (Bus Bars) 10-21
Power and Energy 10-21
Power in an Electrical Circuit 10-21
Power Formulas Used in the Study of Electricity 10-22
Power in a Series and Parallel Circuit 10-23
Energy in an Electrical Circuit 10-23
Sources of Electricity 10-23
Pressure Source 10-23
Chemical Source 10-23
Thermal Sources 10-24
Light Sources 10-24
Schematic Representation of Electrical Components 10-24
Conductors 10-24
Types of Resistors 10-25
Fixed Resistor 10-25
Carbon Composition 10-25
Resistor Ratings 10-25
Wire-Wound 10-27
Variable Resistors 10-27
Rheostat 10-28
Potentiometer 10-28
Linear Potentiometers 10-29
Tapered Potentiometers 10-29
Thermistors 10-29
Photoconductive Cells 10-29
Circuit Protection Devices 10-30
Fuse 10-30
Current Limiter 10-30
Circuit Breaker 10-30
Arc Fault Circuit Breaker 10-31
Thermal Protectors 10-31
Control Devices 10-31
Switches 10-31
Toggle Switch 10-31
Pushbutton Switches 10-32
Microswitches 10-33
Rotary Selector Switches 10-33
Lighted Pushbutton Switches 10-33
DIP Switches 10-34
Relays 10-34
Series DC Circuits 10-34
Introduction 10-34
Voltage Drops and Further Application of Ohm’s Law 10-35
Voltage Sources in Series 10-36
Kirchhoff’s Voltage Law 10-36
Voltage Dividers 10-37
Determining the Voltage Divider Formula 10-39
Parallel DC Circuits 10-40
Overview 10-40
Voltage Drops 10-40
Total Parallel Resistance 10-40
Resistors in Parallel 10-41
Two Resistors in Parallel 10-41
Current Source 10-41
Kirchhoff’s Current Law 10-41
Current Dividers 10-42
Series-Parallel DC Circuits 10-42
Overview 10-42
Determining the Total Resistance 10-43
Alternating Current and Voltage 10-44
AC and DC Compared 10-44
Generator Principles 10-44
Generators of Alternating Current 10-46
Position 1 10-47
Position 2 10-47
Position 3 10-48
Position 4 10-48
Position 5 10-48
Cycle and Frequency 10-48
Cycle Defined 10-48
Frequency Defined 10-48
Period Defined 10-49
Wavelength Defined 10-49
Phase Relationships 10-49
In Phase Condition 10-49
Out of Phase Condition 10-49
Values of Alternating Current 10-50
Instantaneous Value 10-50
Peak Value 10-50
Effective Value 10-50
Capacitance 10-51
Capacitors in Direct Current 10-51
The RC Time Constant 10-51
Units of Capacitance 10-52
Voltage Rating of a Capacitor 10-52
Factors Affecting Capacitance 10-52
Types of Capacitors 10-53
Fixed Capacitors 10-53
Variable Capacitors 10-54
Capacitors in Series 10-54
Capacitors in Parallel 10-55
Capacitors in Alternating Current 10-55
Capacitive Reactance Xc 10-55
Capacitive Reactances in Series and in Parallel 10-56
Phase of Current and Voltage in Reactive Circuits 10-56
Inductance 10-57
Characteristics of Inductance 10-57
The RL Time Constant 10-58
Physical Parameters 10-58
Self-Inductance 10-58
Types of Inductors 10-59
Units of Inductance 10-59
Inductors in Series 10-59
Inductors in Parallel 10-59
Inductive Reactance 10-60
AC Circuits 10-61
Ohm’s Law for AC Circuits 10-61
Series AC Circuits 10-61
Parallel AC Circuits 10-63
Resonance 10-65
Power in AC Circuits 10-66
True Power Defined 10-66
Apparent Power Defined 10-66
Transformers 10-66
Current Transformers 10-69
Transformer Losses 10-69
Power in Transformers 10-69
DC Measuring Instruments 10-69
D’Arsonval Meter Movement 10-70
Current Sensitivity and Resistance 10-70
Damping 10-71
Electrical Damping 10-71
Mechanical Damping 10-71
A Basic Multirange Ammeter 10-71
Precautions 10-72
The Voltmeter 10-72
Voltmeter Sensitivity 10-72
Multiple Range Voltmeters 10-72
Voltmeter Circuit Connections 10-73
Influence of the Voltmeter in the Circuit 10-73
The Ohmmeter 10-73
Zero Adjustment 10-73
Ohmmeter Scale 10-74
The Multirange Ohmmeter 10-74
Megger (Megohmmeter) 10-75
AC Measuring Instruments 10-76
Electrodynamometer Meter Movement 10-76
Moving Iron Vane Meter 10-76
Inclined Coil Iron Vane Meter 10-78
Varmeters 10-78
Wattmeter 10-78
Frequency Measurement/Oscilloscope 10-79
Horizontal Deflection 10-79
Vertical Deflection 10-80
Tracing a Sine Wave 10-80
Control Features on an Oscilloscope 10-80
Flat Panel Color Displays for Oscilloscopes 10-82
Digital Multimeter 10-82
Basic Circuit Analysis and Troubleshooting 10-82
Voltage Measurement 10-82
Current Measurement 10-83
Checking Resistance in a Circuit 10-83
Continuity Checks 10-84
Capacitance Measurement 10-84
Inductance Measurement 10-85
Troubleshooting the Open Faults in Series Circuit 10-85
Tracing Opens with the Voltmeter 10-85
Tracing Opens with the Ohmmeter 10-86
Troubleshooting the Shorting Faults in Series Circuit 10-86
Tracing Shorts with the Ohmmeter 10-87
Tracing Shorts with the Voltmeter 10-87
Troubleshooting the Open Faults in Parallel Circuit 10-87
Tracing an Open with an Ammeter 10-88
Tracing an Open with an Ohmmeter 10-88
Troubleshooting the Shorting Faults in Parallel Circuit 10-89
Troubleshooting the Shorting Faults in Series-Parallel Circuit 10-89
Logic in Tracing an Open 10-89
Tracing Opens with the Voltmeter 10-90
Batteries 10-90
Primary Cell 10-90
Secondary Cell 10-90
Battery Ratings 10-92
Life Cycle of a Battery 10-92
Lead-Acid Battery Testing Methods 10-92
Lead-Acid Battery Charging Methods 10-93
Nickel-Cadmium Batteries 10-94
Chemistry and Construction 10-94
Operation of Nickel-Cadmium Cells 10-94
General Maintenance and Safety Precautions 10-95
Sealed Lead Acid Batteries 10-95
Inverters 10-96
Rotary Inverters 10-96
Permanent Magnet Rotary Inverter 10-96
Inductor-Type Rotary Inverter 10-98
Static Inverters 10-98
Semiconductors 10-101
Doping 10-101
PN Junctions and the Basic Diode 10-102
Forward Biased Diode 10-103
Reverse Biased Diode 10-104
Rectifiers 10-104
Half-Wave Rectifier 10-105
Full-Wave Rectifier 10-106
Dry Disk 10-106
Types of Diodes 10-107
Power Rectifier Diodes 10-107
Zener Diodes 10-107
Special Purpose Diodes 10-108
Light-Emitting Diode (LED) 10-108
Liquid Crystal Displays (LCD) 10-108
Photodiode 10-108
Varactors 10-108
Schottky Diodes 10-108
Diode Identification 10-109
Introduction to Transistors 10-109
Classification 10-109
Transistor Theory 10-109
PNP Transistor Operation 10-111
Identification of Transistors 10-111
Field Effect Transistors 10-111
Metal-Oxide-Semiconductor FET (MOSFET) 10-112
Common Transistor Configurations 10-112
Common-Emitter Configuration 10-112
Common-Collector Configuration 10-113
Common-Base Configuration 10-113
Vacuum Tubes 10-113
Filtering 10-114
Filtering Characteristics of Capacitors 10-114
Filtering Characteristics of Inductors 10-114
Common Filter Configurations 10-115
Basic LC Filters 10-115
Low-Pass Filter 10-116
High-Pass Filter 10-116
Band-Pass Filter 10-117
Band-Stop Filter 10-117
Amplifier Circuits 10-118
Classification 10-118
Class A 10-118
Class AB 10-118
Class B 10-119
Class C 10-119
Methods of Coupling 10-120
Direct Coupling 10-120
RC Coupling 10-120
Impedance Coupling 10-120
Transformer Coupling 10-120
Feedback 10-121
Operational Amplifiers 10-121
Applications 10-122
Magnetic Amplifiers 10-122
Saturable-Core Reactor 10-123
Logic Circuits 10-124
Logic Polarity 10-124
Positive 10-124
Negative 10-124
Pulse Structure 10-124
Basic Logic Circuits 10-125
The Inverter Logic 10-125
The AND Gate 10-125
The OR Gate 10-126
The NAND Gate 10-127
The NOR Gate 10-127
Exclusive OR Gate 10-128
Exclusive NOR Gate 10-128
The Integrated Circuit 10-128
Microprocessors 10-130
DC Generators 10-130
Theory of Operation 10-130
Generation of a DC Voltage 10-131
Position A 10-132
Position B 10-132
Position C 10-132
Position D 10-133
The Neutral Plane 10-133
Construction Features of DC Generators 10-133
Field Frame 10-133
Armature 10-134
Gramme-Ring Armature 10-135
Drum-Type Armature 10-135
Commutators 10-136
Armature Reaction 10-137
Compensating Windings 10-137
Interpoles 10-138
Types of DC Generators 10-138
Series Wound DC Generators 10-138
Shunt Wound DC Generators 10-139
Compound Wound DC Generators 10-139
Generator Ratings 10-140
Generator Terminals 10-141
DC Generator Maintenance 10-141
Inspection 10-141
Condition of Generator Brushes 10-141
DC Motors 10-142
Force between Parallel Conductors 10-143
Developing Torque 10-143
Basic DC Motor 10-144
Position A 10-145
Position B 10-145
Position C 10-145
Position D 10-145
DC Motor Construction 10-146
Armature Assembly 10-146
Field Assembly 10-147
Brush Assembly 10-147
End Frame 10-147
Types of DC Motors 10-147
Series DC Motor 10-147
Shunt DC Motor 10-148
Compound DC Motor 10-148
Counter Electromotive Force (emf) 10-149
Types of Duty 10-149
Reversing Motor Direction 10-149
Motor Speed 10-150
Energy Losses in DC Motors 10-151
Inspection and Maintenance of DC Motors 10-152
AC Motors 10-153
Types of AC Motors 10-153
Three Phase Induction Motor 10-153
Rotating Magnetic Field 10-153
Construction of Induction Motor 10-154
Induction Motor Slip 10-154
Single Phase Induction Motor 10-155
Shaded Pole Induction Motor 10-155
Split Phase Motor 10-156
Capacitor Start Motor 10-156
Direction of Rotation of Induction Motors 10-156
Synchronous Motor 10-157
AC Series Motor 10-159
Maintenance of AC Motors 10-160
Alternators 10-160
Basic Alternators and Classifications 10-160
Method of Excitation 10-160
Number of Phases 10-161
Armature or Field Rotation 10-161
Single Phase Alternator 10-161
Two Phase Alternator 10-162
Three Phase Alternator 10-162
Wye Connection (Three Phase) 10-162
Delta Connection (Three Phase) 10-162
Alternator Rectifier Unit 10-163
Brushless Alternator 10-163
Alternator Rating 10-165
Alternator Frequency 10-165
Alternator Maintenance 10-165
Regulation of Generator Voltage 10-167
Voltage Regulation with a Vibrating-TypeRegulator 10-167
Three Unit Regulators 10-167
Differential Relay Switch 10-169
Overvoltage and Field Control Relays 10-170
Generator Control Units (GCU) 10-170
Basic Functions of a Generator Control Unit 10-170
Voltage Regulation 10-170
Overvoltage Protection 10-170
Parallel Generator Operations 10-170
Over-Excitation Protection 10-170
Differential Voltage 10-170
Reverse Current Sensing 10-170
Alternator Constant Speed Drive System 10-171
Hydraulic Transmission 10-172
Voltage Regulation of Alternators 10-178
Alternator Transistorized Regulators 10-178
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