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Re: Scopes Away! - mosfet



On Tue, 8 Oct 1996, Tesla List wrote:
> What abt switching the rectified primary of the neon xfmr etc at
> resonance with MOSFETS or would you need a ferrite at these frequencies
> I suspect that you might ---- just thought I would throw this in the
> melting pot

High voltage is no solution. Getting mosfets for around 1kV or so
is not cheap any more. And 1kV ain't much yet! Over here 400-600V
mosfets will switch most power for the buck. IGBTs are cheapest
if the frequency is not too high. They are still quite slow compared
to MOSFETs capable of switching even in the range of few MHz!!

Perhaps I should investigate with IGBTs too. I just have been afraid
to throw my only 1000V/50A half bridge module into anything. If I
managed to blow it up I would not afford another. :( Besides, it is
great for keeping the papers in place! :)

Anyway, if good switches were available for high voltages you would not
need a ferrite if voltage step-up is not needed. However, they can also be
used to get isolation from the 50/60Hz signals which usually can be a
pretty nice point. Vacuum tubes are sometimes used to do stuff like that.
--
"99% of the pain in the world is due to misunderstanding" -M. Jarvelainen

Harri.Suomalainen-at-hut.fi - PGP key available by fingering haba-at-alpha.hut.fi