Effective value

The value obtained by converting an AC voltage or current into an equivalent DC voltage or current that produces the same amount of work. The calculation method is to integrate the square of the instantaneous value of the AC waveform over one period, divide it by the period, and then take the square root of that value. For example, in the case of a sinusoidal AC voltage, if the peak value (maximum value) is Vm, the effective value Ve is expressed by the following formula.

Ve = Vm/√2

In daily life, this value is commonly used to indicate the magnitude of AC voltage and current. For example, the 100V of a household outlet is the effective value, and the maximum value (peak value) is √2 times that, which is 141.4V.