Amps x Ohms measures electrical power, which is expressed in watts (W). This relationship is defined by Ohms Law, which states that voltage (V) is equal to the product of current (I) and resistance (R), or V = I x R, which can also be expressed as W = V x I = I^2 x R = V^2 / R. Therefore, if you know the current and resistance in a circuit, you can calculate the power being used by multiplying them together.