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Re: QDX MOSFET Heat Sinks


 

Yes, Jim? that is correct. Some day it could wind up somewhere that has no such control. My conscience is quieter if I don't use it.

BTW, do you remember the BeO envelopes on high power transmitting tubes? Same safety consideration noted.

73, JZ

On Sat, Jan 6, 2024, 1:03?PM Jim Strohm <jim.strohm@...> wrote:
John,?

The article you cited includes this:

"the material (beryllium oxide) is safe to handle as long as dust is not generated during machining or handling."

73
Jim N6OTQ



On Sat, Jan 6, 2024 at 11:15?AM John Z <jdzbrozek@...> wrote:
Hi Don,

I had a similar thought, but then did a bit more digging.

I found that Kyocera also offers a similar thermal product called Q-Bridge:



Most of those are also Aluminum Nitride, although some are made of Beryllium Oxide, which is quite toxic.

Unlike most electrical insulators, which have very poor thermal conductivity, those two ceramics possess thermal conductivity on par with metals.

Pretty cool! (pardon silly pun :-)

This class of part could be extremely useful as the envelope gets pushed on cig-pack sized Ham radios!

73,? JZ






On Sat, Jan 6, 2024, 11:10?AM Donald S Brant Jr <dsbrantjr@...> wrote:
On Sat, Jan 6, 2024 at 07:16 AM, John Z wrote:
The thermal wick chips I mentioned in the previous post offer an
interesting possibility for the future (especially if the price comes
down!)
Those "thermal wicks" sure look a lot like a regular chip resistor with no element; maybe that is exactly what they are.?
I wonder what the thermal properties of an ordinary high-value (1M?)chip resistor might be.....??
The few I looked into had alumina substrates; not as good as aluminum nitride but better than air or PCB material.
73, Don N2VGU??

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