Don Foreman wrote:
On Sat, 15 Jan 2011 23:58:39 -0600, Ignoramus25553

Guys, can I ask an ignorant question. I thought that voltage drop
depends on the maximum reverse voltage that the diode would withstand?
Is that true or not?

In other words, is the voltage drop on a 1,000V rated diode, the same
as on a 30v rated diode?

The forward voltage of a diode depends on quite a few variables
including geometry, doping levels, current and temperature. If Vf is
important to a design, it's always best to consult the data sheet to
see what Vf will be with a particular part at the anticipated current
level and temperature.

Those packaged 25 to 35 amp bridges tend to have Vf of about 1.1 volt
per diode at rated current, and this is essentially independent of the
peak inverse voltage rating. Vf of 0.7 volts is seen at lower
current, perhaps a couple of amps. Vf varies about logarithmically
with If.

FWIW, I concur with Don here, but I've only been an electronics tech
(and sometime de facto "engineer") for about forty years now. ;-)

Cheers!
Rich