Paul,
At the output of your 1:n transformer (non CT), you will get nVp-2Vf
peak voltage measured across the FWB + and - terminals. Since Vp = Vave
for the square wave, the DC output will be nVp-2Vf as well.
Tomm
------------------------------------
Alex,
Starting with a 1:n non CT transformer and primary peak voltage Vp, the
FWB will give a peak output across its terminals of nVp-2Vf where Vf is
the forward drop of the single diode. Connecting a bridge to the AC
line directly will confirm this operation. You may be thinking of the
textbook comparisons of FWCT and FWB in which the baseline transformer
secondary is a center tapped winding with each half having the full
ratio to the primary (1:n:n). In this case, the FWCT gives an output
peak of nVp-Vf with respect to the center tap and the FWB gives an
output peak of 2nVp-2Vf across the FWB output terminals. This is NOT
because of some doubling action of the FWB but because you are
connecting it across twice the number of turns needed to produce nVp-2Vf.
Tomm
Paul Decker wrote:
>
> OK amp builders....
>
>
>
> Which is it! --- I'm feeling unsure of myself again.
>
>
>
> The picture in my book for full wave bridge and a sine wave says:
>
>
>
> Epk = 1.4 Erms.
>
> Eav = 0.9 Erms
>
>
>
> It also seems to depict the pk - pk value, the negative peaks
> "flipped" up to become positive peaks, this to me would imply that you
> now only have more of the same size positive peaks
>
> BTW, it says the same for a full wave center tap, only that the piv
> seen on the diodes is higher.
>
>
>
>
>
> Now since I'm using a square wave, what happens? I finally found a
> reference which said
>
> Epk = Erms = Eav
>
>
>
>
>
> Thanks for any extra clarification,
>
>
>
> Paul, kg7hf.
>
>
>
> ----- Original Message -----
> From: "Alex Eban" <alexeban@gmail.com>
> To: "KD7QAE" <KD7QAE@ARRL.NET>, "Paul Decker" <kg7hf@comcast.net>
> Cc: amps@contesting.com
> Sent: Wednesday, April 1, 2009 3:23:32 AM GMT -05:00 US/Canada Eastern
> Subject: RE: [Amps] winding an HV transformer
>
> Not correct!
> With a full bridge rectifier you get the peak to peak voltage out as DC!
> All the diodes do is redirect the transformer secondary to the correct
> polarity.
> What you wrote pertains to double rectification with a pair of diodes
> and a
> center tapped transformer secondary.
> Alex 4Z5KS
>
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