Jim Paul wrote:
>
> All,
>
> Does anyone have any ideas for high voltage transistors?  I need some with
> a BVCEO of between 1200 and 3000 VDC.  I know this is quite an order, but
> I don't see any way aorund it at this time.  If no transistors are available, some
> high voltage op amps are available from APEX, but at $550.00 per amp, and I
> need two, that gets quite expensive.  Anyway, if anyone has any ideas, let me
> know.


That spec is often seen in the TV industry, not
common but available. Try some of the T0-3 types
used in older Sanyo sets, 2500v/3000v 5A is common.

Also, I have seen some TV manufacturers errata
sheets that show these transistors can be replaced
with more common (lower volt spec) types, usually
with the addition of a simple snubber consisting of
a 6kv ceramic and a resistor.

I think the big problem is the slew rate, if you slow
the change of voltage across the transistor, the
higher voltage can be better tolerated. From memory,
one errata sheet showed the 3000v transistor could be
replaced by a much more common 2000v one simply by
adding the snubber.

Hope that helps, I you want part numbers I can check
further. If you have a modern transistor book, look for
all the transistors marked as "TV h-out" and you should
find something. :o)
-Roman

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu