Watt's law

"Watt's law" is an improper name used for the "Basic Power Formula:"

:$P\; =\; V\; cdot\; I$

where :$P$ is the power in watts:$V$ is the potential difference in volts:$I$ is the current in amperes

The basic power formula is used to calculate the electrical power $P$ dissipated in a resistor or a circuit, given the voltage $V$ across it and the current $I$ flowing in it. The voltage drop across a resistor is also referred to as the potential difference.

It is sometimes designated by "E" or "U" instead of "V".

When combined with Ohm's law, Watt's law can be rewritten as:

:$P\; =\; I^2\; cdot\; R$

where :"R" is the electrical resistance in ohms.

References