A couple of Bondwell 2 questions

From: Bill Dawson <whdawson_at_mlynk.com>
Date: Sun Nov 5 21:43:34 2000

-> On Sun, 5 Nov 2000, Claude wrote:
->
-> > Bill Dawson wrote:
-> > > disks. The only markings on Q1, TO-92'ish, are A854 (date code
or
-> > > 2SA854?) and S G D. I think this device is in the circuit to
save
->
-> > Quickly I would say its a 2sa854 very common but S,G,D should be
for
-> > Source, Drain, Gate for FET transistors...could be a fet with that
-> > number...

Yes, FET, not SCR. I know what S, G and D stand for. Lack of sleep
contributes to mistakes.

->
-> I use this part at work all the time. It is a 2SA854, simple bipolar
PNP,
-> I(c) of 500 mA maximum, just a general-purpose transistor. The SGD
on the
-> bottom is probably a lot/date code.

Well, the leads are not evenly spaced. The S and G leads are closer
together than the G and D leads, and the S, G and D markings are exactly
over each lead.

-> The leads are, facing the side with
-> the markings on it, emitter/collector/base. This is why shorting the
-> first two makes it work.
->
-> Make sure you have proper signal at the base, then replace if
necessary; a
-> 2N3906 will sub but has a different pinout and (I think) not quite
the
-> same I(c) rating. There is a spec sheet at the Rohm website.

I guess I may have to draw up a schematic of the circuit to figure out
what's going on, if no one has it. I didn't write down the part number
of the stepper motor driver, but I think it needs more current than a
small signal transistor can pass.

Bill

->
-> Richard Schauer
-> rws_at_enteract.com
->
Received on Sun Nov 05 2000 - 21:43:34 GMT