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Author Topic: What's the highest frequency people have tested IRF series MOSFETs?  (Read 247 times)

Offline Kage

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Not sure where I saw the schematic but there was one someone made showing it was possible
to get around 5W(?) out on the low side of the FM broadcast band. Can't remember if it was the
IRF510 but it was in that ballpark. I'm sure the efficiency would be laughable but possibly still
useful.

I'd think the gate capacitance would become so high that they would be useless in the lower VHF
range but I've never actually tried to see the limits.

Seems there are hams who use them in the 6m band so if they can do 50MHz that begs the question
where will the maximum usable frequency of amplification become basically unity gain (if I should
call it that), or useful amount of amplification before it's useless?
I'm not saying aliens are in the radio, but aliens definitely are in the radio.
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Offline redhat

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In commercial designs, 13-15 MHz is about the limit for power devices in the 500W class.  Smaller fets you should be able to run quite a bit higher, although 40-50 MHz is likely the practical limit.

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