Re: gEDA-user: Exposed copper -- still need to make a pad?

[John Doty <jpd@xxxxxxxxxxxxx>]

On Sep 27, 2007, at 10:41 AM, Larry Doolittle wrote:

>
> OTOH, your radiator has to get quite hot to carry away much
> heat by infrared radiation.  Presumably you have some airflow,
> either passive (convection) or active (fan-driven).  Then you
> want exposed metal, and its emissivity doesn't matter much.

You'd be surprised at how much gets carried away by radiation. For  
things like resistors, 2X derating relative to natural convection is  
generally sufficient in a vacuum. But if you calculate the thermal  
resistance of a thin plastic film over metal, you'll find it's  
negligible.

John Doty              Noqsi Aerospace, Ltd.
http://www.noqsi.com/
jpd@xxxxxxxxx




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