Page 9 - Teach Yourself Electricity and Electronics

Contents ix

Voltage across parallel resistances 85
Currents through parallel resistances 86
Power distribution in series circuits 88
Power distribution in parallel circuits 88
Kirchhoff’s first law 89
Kirchhoff’s second law 91
Voltage divider networks 92
Quiz 95

6 Resistors 99
Purpose of the resistor 99
The carbon-composition resistor 102
The wirewound resistor 103
Film type resistors 104
Integrated-circuit resistors 104
The potentiometer 105
The decibel 107
The rheostat 109
Resistor values 110
Tolerance 110
Power rating 110
Temperature compensation 111
The color code 112
Quiz 114

7 Cells and batteries 118
Kinetic and potential energy 118
Electrochemical energy 118
Primary and secondary cells 119
The Weston standard cell 120
Storage capacity 120
Common dime-store cells and batteries 122
Miniature cells and batteries 124
Lead-acid cells and batteries 125
Nickel-cadmium cells and batteries 125
Photovoltaic cells and batteries 127
How large a battery? 128
Quiz 130
8 Magnetism 134
The geomagnetic field 134
Magnetic force 135
Electric charge in motion 136
Flux lines 136
Magnetic polarity 137
Dipoles and monopoles 139