At 02:17 PM 13/03/2012, you wrote:

>Hello,
>
>could anyone please suggest a cheap NPN transistor rated at least=20
>400V and with a
>current capability of at least 1.5A and a gain (at that current) of=20
>at least 100?
>
>Possibly not a darlington.
>
>If such a toy even exists. :P I can't find one.. a cheap one at=20
>least, but maybe
>I'm missing some classic high voltage ~1.5A power transistor with high gai=
n? I
>need to use it as a switch, but I don't wanna use a MOSFET in this=20
>circuit, for
>a lot of considerations (cost, ease of drive, number of components=20
>on the PCB..).
>
>Thanks!
>Mario

It's unlikely you'll find a simple high voltage BJT with that much gain at =
high
current. A beta of around 10 is more like it. MJE13007 has a minimum gain o=
f 8
at 2A, for example.

MOSFETs are cheap and plentiful, but the high voltage ones generally=20
want 10V of
gate drive.

As M.L. suggests a buffer transistor driving a HV BJT is probably not a bad
way to go if you've got the 150mA or whatever to drive the base (from the
logic supply). You could use a low voltage MOSFET or small BJT such=20
as a 2N4403
or 2N4401 (a couple of cents).

Best regards,




--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.