The RMS or effective value of any AC waveform is an equivalent dc value that provides information about how many volts or amps of DC a time-varying waveform is equal to in terms of its capability to deliver average power.
The effective value of any waveform depends on the type. The most famous example of waveforms around us is the AC waveform at wall outlets in our homes. In most North American countries, the value of the waveform is 120 Vac. The number 120 is the RMS value, implying that the sinusoidal voltage at the wall outlets can deliver the same average power as 120 volts of steady DC.
Formula for Effective Value of Sine Wave
Given below are a few formulas for calculating effective values of Sine Wave:
Ieff = Im/√2 = 0.707 Im
Where
Ieff = Effective or RMS value of a current waveform
Im = Peak value of the current waveform
Veff = Vm/√2 = 0.707 Vm
Where
Veff = Effective or RMS value of voltage waveform
Vm = Peak value of voltage waveform
To calculate peak values from effective values
Im = √2 * Ieff = 1.414*Ieff
Vm = √2 * Veff = 1.414*Veff