> With the glitch R in the negative return, the cathode circuitry may be
> driven to several kV by a B+ to chassis arc.
Good point.
I don't like the idea of most of the HT appearing across the filament
transformer secondary...
Perhaps the OE5JFL circuit should have string of diodes in parallel with
the sensing resistor in the B- line, to limit the voltage drop to a few volts.
And a separate glitch resistor in B+, where it belongs.
Even better: get rid of the B- sensing & glitch protection completely.
Use a glitch resistor in B+ to also trigger an opto SCR like the H11C4.
They are good for 7.5 kV of isolation and don't cost much.
> >However, that's no a problem because thyristors will trigger quite
> >happily due to a voltage step.
I had forgotten about dV/dt triggering. Good point. No doubt it would
work as intended.
I am considering putting something along these lines in my 2.5 kV
supply
Wilbert, ZL2BSJ
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