The simplest solution, assuming the reverse voltage rating can take it,
is to use Schottky devices, The drop will be much less, so heating will
be manageable.

Schottky diodes also switch faster, further reducing the heat losses.

--Bob

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.
>
>Thoughts? Experiences?
>
>
>        Russell McMahon
>
>
> 
>
>  
>


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