Heatsink questions.

[The little lost angel]

The specifications for some parts lists the heatsink required as a
figure like say 100 x 100 x 2.5mm

Others differentiate between chassis and finned but doesn't give a
size.

Am I correct in thinking, based on the 2nd type of specifications,
that a heatsink of say 50 x 50 x 2.5 mm with fins on it that make up
another 50 x 50 x 2.5 mm of mass would do just as good as a flat piece
of 100 x 100 x 2.5mm?

Thanks!

--
L.Angel: I'm looking for web design work.
If you need basic to med complexity webpages at affordable rates, email me
Standard HTML, SHTML, MySQL + PHP or ASP, Javascript.
If you really want, FrontPage & DreamWeaver too.
But keep in mind you pay extra bandwidth for their bloated code

 

[Costas Vlachos]

"The little lost angel" <a?n?g?e?l@lovergirl.lrigrevol.moc.com> wrote in
message news:3fddd9c3.137869295@news.pacific.net.sg...

The specifications for some parts lists the heatsink required as a
figure like say 100 x 100 x 2.5mm

Others differentiate between chassis and finned but doesn't give a
size.

Am I correct in thinking, based on the 2nd type of specifications,
that a heatsink of say 50 x 50 x 2.5 mm with fins on it that make up
another 50 x 50 x 2.5 mm of mass would do just as good as a flat piece
of 100 x 100 x 2.5mm?

Thanks!

What you need to consider is both the mass and the surface area. The fins in
a heatsink enable a large surface area to be contained in a small space,
thus greatly increasing its thermal dissipation. The larger the surface area
the better the dissipation. This means that two heatsinks of equal mass may
have significantly different thermal dissipation characteristics depending
on their shape and total surface area (i.e., a finned heatsink should be
better than a flat piece of the same mass).

BTW, your numbers above are not right: The flat piece has twice the mass of
the finned heatsink - unless that's what you meant to say.

Costas