Electricity Question

Thanks Glenn F.

Amps is the unit for electic current, 1 amp equals one coulomb of charge per second.)

As the others have said, in a DC circuit or purely resistive AC circuit, power in watts equals volts times amps.

For an inductive or capacitive ac load watts no longer equals volts times amps. This is due to the phase difference between current and voltage. You must multiply volts times amps times "power factor" to get the true power in watts.

Power factor, which is the cosine of the phase angle between voltage and current, cannot be easily measured using tools most of us have (generally it's done with a phase-angle voltmeter or an oscilloscope). You either have to use the manufacturer's published power factor, or else guess. 0.7 is as good a guess as any for typical inductive loads like motors. So if you were trying to figure power consumption of a 120V motor rated at 10 amps, it would be 120 x 10 x 0.7 = 840 watts.