"ArameFarpado" wrote in message
...
Em Sábado, 19 de Abril de 2008 20:18, Brian Gregory [UK] escreveu:

"ArameFarpado" wrote in message
...
Hi all...

a transistor "BD435" is giving me 440 in hFE test on the multimeter,
when
the tecnical data i've found tell me min=40 max=475...

does this mean the transistor is really in good shape?

Probably.

can it be busted and still give a good hFE test result on the
multimeter?

It depends how good the multimeter's Hfe function is.
Agreed

Check that if you disconnect B and connect only C and E the meter shows
either a low number (ideally 0 or no more than 1 or 2) or an error of
some
kind.

connecting just E and C in the socket, it reads the same value for hFE.

The transistor's f***ed.

so, it got me thinking that hFE measure is not a transistor test for
working/burned transistor...

do you use hFE measure to see if a transistor is busted?

It's only quite recently that I've owned a meter with a transistor test
function on it. I normally do what I used to do and use a highish ohm range
and a wet finger to apply bias to the transistor. You check that the wet
finger produces much more deflection (lower reading on a DMM) when used to
apply bias than it does when applied directly across the probes. If you want
to be a bit more scientific you replace the wet finger with a resistor of
known value.

thanks
ArameFarpado

--

Brian Gregory. (In the UK)

To email me remove the letter vee.