TexasRF@aol.com wrote:
> I found out the hard way that 1A and 3A protection diodes can't
> handle a 3000vdc plate to ground arc. A good sized hv filter C, say
> 50uF, stores enough energy to destroy them, even with a series 50 ohm
> current limiting resistor. A 6A diode does seem capable of
> discharging the energy without failure but that is where the rise
> time question comes in.
Given the prices of different options, I use a 35A bridge so there's two
diodes in series back to back, and design the metering for <1V FSD. No
worries about surge ratings.
On a similar note, I've had scrren supply zener (5W) strings blow on
plate-screen arcs, even with MOVs in place. A 375V MOV clamps at around 600V
at arc current, so the zeners end up taking all the strain - but not for
long.
Steve
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