On Tue, 22 Jan 2008 02:56:36 -0500, "Bob"
wrote:

Hi Richard, Would you check out this link:
http://www.bourns.com/components.aspx?cmsphid=7631383|7163299|3412571

Which one will be the best for let say, 400 Watts dummy? Thank you.
Regards. Bob

Hi Bob,

There is every probability that either of your links will work,
although I still have a sample request that remains to be filled (but
I am in contact with their engineers).

However, backing up to the actual application, this is still not a
done deal if you are trying to push them to their "ratings." The
larger part of success is in the details, and for Heat Transfer, that
is a devil.

The practical solution will require a sink with fins and forced air in
ambient to still find it derated by 60%. Ham applications rarely
subject a dummy load to full power continuously, however. So, a good
heat sink and a one minute application of full rating in ten minutes
"may" be tolerated. You can always water cool them.

73's
Richard Clark, KB7QHC