>> //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.
** At this QTH, the hotter the junction gets, the lower the Vf. Try
some espresso.
>> 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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>> http://lists.contesting.com/mailman/listinfo/amps
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>
- R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
www.vcnet.com/measures.
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