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On 12/5/20 4:55 AM, Don86326 wrote:
Hello Tesla builders,
Here is a design overview for critique... maybe experience in the TC
list will save me a buck or two. Comment on design overview for me
please. . .
The design is intended to drive a dipole loop in two halves such that it
oscillates beginning at the 2nd harmonic (typically --but this case is a
non-harmonic experiment).
I want to buy the new eGaN transistors for a try-out. They are nearly
an ideal transistor, with tremendous slew rates. (About 12 volt skew per
nanosecond.) They conduct hundreds of amps in short bursts, up to 200
Volts. They do not suffer from thermal-runaway, because they conduct
less when warm. This allows them to be ganged with no runaway protection
needed.
Can anyone share any experience with eGaN transistors? Did someone drive
a football coil with these, I think David Thompson shared.
I've not used GaN myself, but at work (JPL) , there's a lot of stuff
being done because of several interesting things:
1) They tolerate high temperatures well - which means easier cooling
(space stuff cools by radiation so the T^4 term gets big real fast.
Cooling something at 200C is a lot faster (6x) than something at 25C.
2) They're rad hard
3) They're low loss - for RF and microwave amplifiers - solid state is
about 25% efficient for conventional designs. GaN might get to 50% or
better, competing with vacuum tubes.
For TC down at hundreds of kHz, the efficiency should be even better.
Probably don't care as much about rad hard. Tolerate high temps is good
there, too - run the heat sink hotter, and for the same air flow, you
move more heat away.