What is the formula for calculating current if voltage and power are known, but resistance or impedance is unknown?
For DC Circuits (Using Power and Voltage)In a direct - current (DC) circuit, the power P (in watts), voltage V (in volts), and current (in amperes) are related by the formula P=VIIf we know the power P and voltage V, we can calculate the current using the formula I=P/V. For example, if a DC device has a power rating of 100 watts and is connected to a 20- volt source, then the current I=100/20=5 amperese.In an alternating - current (AC) circuit, we deal with apparent power S (in volt - amperes),