Electrical Energy, Power
The electric power in watts associated with a complete electric circuit or a circuit component represents the rate at which energy is converted from the electrical energy of the moving charges to some other form, e.g., heat, mechanical energy, or energy stored in electric fields or magnetic fields.
For a resistor in a D C Circuit the power is given by the product of applied voltageand the electric current.
The electric power required to operate a device is the input voltage times the current required.
P = VI where
P = electric power
V = voltage used
I = current in amperes
VI is V times I
Electric power is measured in watts. If the amount of watts is large, kilowatts are used. 1 kilowatt = 1000 watts, just as 1 kilometer = 1000 meters. The abbreviation for kilowatt is usually kW.