In applying Ohm's law to AC circuits, current and voltage values are:

When applying Ohm's Law (E = I x R) to AC circuits, you must use the equivalent DC values to ensure the math works correctly for power and dissipation. This equivalent DC value is known as the Root Mean Square (RMS) or effective value. For a perfect sine wave, the RMS value is found by multiplying the peak value (the maximum amplitude of the wave) by the constant 0.707, which is 1 divided by the square root of 2. Using average values or multiplying by 1.414 (which is used to find peak from RMS) would yield incorrect results for standard Ohm's Law AC calculations.