# Full wave rectification with an offset p-p voltage

#### coinmaster

Joined Dec 24, 2015
502
Well, It's AC from the wall so it's just a 60hz AC signal. What I was asking is if I could get 80v positive 20v negative/ 40v positive 60v negative/ 10 volts positive 90v negative/ etc, etc, etc, from a full wave rectifier as I am building an expensive power supply and I don't want to pay for voltage I'm not using.

#### AnalogKid

Joined Aug 1, 2013
11,201
Yeah sorry I'm a little confused on the difference between rms and p-p.
Without getting into the math behind them, here is the short form for sine waves:

RMS x sqrt2 = Peak
Peak x 2 = Peak to Peak
rearrange as needed

ak

#### crutschow

Joined Mar 14, 2008
34,842
Well... it occurred to me that he could adjust his original AC source using the variac, and then use full bridge rectifiers on each side...

Something like this:

VA-B=100 VAC
VA-C=20 VAC
VC-B = 80 VAC​

Is what I'm saying viable? Or did I just put my foot in my mouth?
I don't see how that would work with a common output DC ground.
Show me how you would hook up the rectifiers to do what you want.