The PIV across each diode in a bridge will be the peak voltage of the
transformer voltage.
In your case with a 1600 vac rms transformer the peak voltage will be 1.414
x 1600 = 2262 volts peak. Each diode in the string must withstand that
amount of reverse voltage. You need 1.5x to 2x safety margin so each diode
should be rated at 3400 volts or so. You may get by with 3000 volts per
diode but 4000 volts would be better.
Just draw a diode bridge circuit and you can easily figure out how much
voltage is across each diode. Consider that at any given time one side of
the transformer is at ground and the other side is connected to the filter
capacitor. Then look at what diodes are reversed biased.
73
Gary K4FMX
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
> On Behalf Of David Feldman
> Sent: Friday, April 20, 2012 12:18 PM
> To: amps@contesting.com
> Subject: [Amps] PIV requirement for identical,individual diodes used in
> a bridge rectifier configuration?
>
>
> In my example, a 1600VAC transformer secondary is connected through
> bridge rectifier (built from 4 individual diodes each rated 2000V PIV;
> current is not a concern here) into a filter capacitor. Do I proceed as
> if the PIV is 4KV (due to two reverse-biased diodes in series), or if
> not, how do I determine the appropriate diode rating requirement?
>
> Thanks very much for any references or suggestions,
>
> Dave
>
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