> //Geesh, I find I have to correct myself! (What else is new?) The Vf
> tempco of a standard Si rectifier isn't negative, it's positive. The
> hotter it gets, the higher the Vf. I still haven't had coffee...gotta go
> for some, I think!
>
> -WB2WIK/6
>
> >
> > //That Vf/If curve, e.g., 734mV/100mA and 813mV/1.2A, may be true for
> the
> > 1N5408 tested, but isn't necessarily representative of all 3A
> rectifiers.
> > In fact, Vf is normally only specified as a "max" at full current, and
> > nowhere else, and can run all over the place. I've seen lots of 3A
> > rectifiers having <<500mV @ 100mA, and >>0.8V @ 1.2A. The "Vf max" of
> > most mil-spec 3A rectifiers, of which the 1N5408 is not (but the very
> > similar 1N5554 is), is 1.0V @ 3A, and of course it has a negative
> tempco,
> > meaning the hotter it gets, the lower the Vf will be. If each rectifier
> > had a 250mV delta Vf, and ten were used in series, this is a 2.5V delta
> > Vf. Could be quite a lot, in some cases.
> >
> > -WB2WIK/6
> >
> >
> >
> >
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