On Sun, Mar 19, 2006 at 04:55:33AM +1200, Russell McMahon wrote:
> Has anyone successfully heat sunk 1N400x diodes?
> 
> Filtering out the
> 
>     - add more copper
>     - change the orientation/location/...
>     - use larger diodes
>     - use a bridge
>     - use a fan
>     - liquid cool / heat pipe / transcendental meditation ...
>     - get a life ...
> 
> responses :-)
> 
> I'm actually interested in things done to get more heat out of 1N400x 
> diodes.
> PCB copper is about at a maximum.
> Lead lengths are small (which is meant to be best)
> They are where they are at present.
> They are operating within nominal spec but get far hotter than I'd 
> like them to.
> (They handle under 1A mean but current is pulsed at rather more so 
> heating is disproportionately high
> 
> 16 diodes are in two parallel rows of 8
> I vaguely toyed with the idea of clamping a heatsink bar along a row.
> Contact an issue - thermal goo or conductive washer.
> Uneven mounting height an issue.
> I can imagine that even a very modestly sized an L or inverse T of 
> aluminum in conduct with the diode bodies would offer far better 
> cooling than at present.
> 
> Coating in a thermally conductive compound that doesn't creep may 
> assist. And may not.

My highly untested advice would be to take a nice big copper bottom heat
sink, and place it ontop of the diodes such that it doesn't short out
anything important. Fill the airspace with thermally conductive potting
compound and you should be set. Hopefully any uneven mounting heights
will be taken up by the compound.

I say copper heatsink because it'll conduct heat better than aluminum
heat sinks, though aluminum radiates heat better...

-- 
pete@petertodd.ca http://www.petertodd.ca
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