On 15/04/2011 00:59, Bob Blick wrote:
> As has been said before, to-220 case parts are not really good for a
> whole lot of heat, 20 watts being thrown around. I concur.
>
> You can get a more if your surfaces are nice and you torque properly.
> But parts are cheap so I'd parallel two if you need 24 watts.
>
> Got a Pentium 4 heatsink/fan combo kicking around? Screw a couple of
> transistors to one of those and you'll be good.

There is a larger TO220 style of package that tab and two outer pins=20
match 3 of the 4 holes of TO3 can, handles much more power. Power FETS=20
from about 50 cent and 12A available. I used a pair of 500V rated ones=20
for a 100W push-pull class AB RF linear amp at 3.6MHz built "dead bug"=20
style on back of Pentium II / Pentium III  heatsink. Pair of 9.1V zeners=20
(clamped to HS) and pots to set bias.



--=20
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