You are very right.  Even a small fan does wonders for cooling.  Most of
my stuff is in small sealed boxes so there is little or no air movement.
 I love it when the customer draws a vacuum on the housing to "prevent
moisture problems" and the electronics cook to death in the resulting
Dewar flask!

Sherpa Doug

> -----Original Message-----
> From: Michael Vinson [mailto:mjvinson@HOTMAIL.COM]
> Sent: Friday, February 15, 2002 10:43 AM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [EE] TO-220 heatsinking
>
>
> Douglas Butler wrote, in part:
> >[...]
> >Fiberglass isn't much of a heat
> >conductor.  But it is much better than air.
>
> Well, it is true that if you only consider true *conduction*,
> air is very poor at transporting heat (this is why a down
> sleeping-bag is so warm: those little feathers keep the air
> from moving, so it can only conduct heat away). But if there
> is room for the air to move, then *convection* can be a very
> efficient heat transport mode. This is, after all, how a
> conventional heat sink ultimately sheds its heat in most cases:
> it presents a large surface area to the air, which convects
> the heat away.
>
> At least, that's what I think. I could be wrong, I'm only a
> humble physicist and not a real electrical engineer.
>
> Michael V
>
> Thank you for reading my little posting.
>
>
> _________________________________________________________________
> Send and receive Hotmail on your mobile device: http://mobile.msn.com
>
> --
> http://www.piclist.com hint: To leave the PICList
> mailto:piclist-unsubscribe-request@mitvma.mit.edu
>
>
>

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