RMS Voltage and Current
In order to work with AC circuits just as we did with DC circuits, we create a voltage and current called rms (root mean square).
Vrms = Vo (1/2)1/2 and Irms = Io (1/2)1/2
Pavg = Irms Vrms and Vrms = Irms R .
Note that the power formula and Ohm’s Law are the same for DC and for AC-rms, but NOT for instantaneous AC.