FWIW, metal and carbon film resistors can dissipate a lot of heat. The factory I worked at, who specialized in precision resistors, found that carbon film resistors on ceramic cores (which is nearly all of them) would run at red heat without damage to the resistance element. I don't know if the test was ever run on metal film resistors but they are probably the same. Of course, it boiled off the conformal coating.
?? Wire wound power resistors (to differentiate them from WW precision resistors) are usually rated at a given temperature rise for the dissipation rating.
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On 11/9/2021 4:19 PM, Chuck Harris wrote:
As was I, and so I said in my post. HP didn't always follow that
advice. The 608F signal generator has a metal film power resistor
in one of its circuits that, by design, dissipated twice its rated
value. Not a good idea, but it worked... and worked... and worked.
I would spend a bit of time trying to verify that the power dissipated
was by design.
-Chuck Harris
On Tue, 9 Nov 2021 21:56:03 +0000 (UTC) "Bob Albert via groups.io"
<bob91343@...> wrote:
I was always taught to hold power dissipation in a resistor to
one-half its power rating. Bob
On Tuesday, November 9, 2021, 01:52:55 PM PST, Richard Merifield
<coitboy2000@...> wrote:
Thanks Chuck
Its a 10w resistor with about 9w dissipation so I guess it is doing
what it was designed to do. As a hobbyist only having worked on a few
solid state amplifiers, all you read suggests avoiding such heat in a
resistor.
Richard
--
Richard Knoppow
dickburk@...
WB6KBL
