R.Measures wrote: > What does "nothing is not defined properly" mean? As I understand > this matter, for AC, V-peak ^2 / R = P-peak, V-rms^2 / R = P-rms. If > the last equation is true, then P-rms = V-rms x I-rms. It isn't true. V-rms^2/R = Pmean (or average). Steve