From: Bill Turner <dezrat1242@wildblue.net>
I'm planning on using one of these in my solid sate PA project
http://www.farnell.com/datasheets/17645.pdf
REPLY:
That is interesting. Do you know what the prices are and where to order
from?
I am paying just over £100 each, say $160, including the fan. Farnell
and Newark have a tie-up so I expect Newark can supply in the US.
Also, I'm curious how your design places a high RF voltage on the
heatsink. Do you mind explaining?
I am planning on using TO-220 high voltage switching FETs which are
primarily targeted at SMPS use. The drain is connected to the mounting
tab. I did look into using a more conventional style of heatsink with an
Alumina plate as a thermally conductive but electrically insulating
interface between a copper heat spreader and the main heatsink, but the
US supplier let me down on delivery and in any case was wildly expensive
for overseas customers. This approach allows me to bolt the FETs
directly to two heatsinks (in a push-pull circuit) and float the whole
assemblies at drain voltage. I don't see this as being much different
from applying an external anode valve.
At the danger of stating the obvious, I do plan on enclosing everything
inside a case for safety!
73, Alan G3XAQ
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