# Vrms, Vpk-pk, Vpk, Vavg for AC signal with DC offset

This might be a dumb question, but what values change when applying a DC offset to an AC signal?

Does Vpk represent the maximum voltage of the signal, in which case it increases directly with the DC offset? Or is it 1/2 the value of the signal Vpk-pk, in which case it would stay the same?

And in that case would Vavg change too?

• When you add these together you have an instantaneous voltage v(t) that likes between Vmin and Vmax with Vavg being the DC level and Vmax-Vmin being the Vac p-p level. The Vrms is now the sum of the AC = (Vac p-p)/(2sq.rt(2)) and the original Vdc component – Tony Stewart Sunnyskyguy EE75 Oct 17 '16 at 4:48
• Yes, Vpk is your peak AC voltage + DC offset. – winny Oct 17 '16 at 7:55
• $V_{rms} = \sqrt{V_{ac_{rms}}^2 + V_{dc}^2}$ – rioraxe Oct 17 '16 at 10:59