inductor insulator inverter kilowatt-hour (kwh) kilowatt-hour meter kilowatt (kw) load load rejection mutual induction ohm ohm's law ohmmeter open circuit parallel circuit piezoelectric polarity power power factor protective relay reactive power rectifier relay reluctance resistance resistor rotor self induction semiconductor series-parallel circuit series circuit service short circuit solid state circuit transistor true power vars variable resistor volt-ampere (va) volt (v) voltage voltmeter watt-hour (wh) watt (w) wattmeter waveform