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My VTTC uses a MOSFET for the interupter, my lamps are penthodes and the MOSFET is connected to the second plate (I don't know how it is called in English) and i use it to pull the coltage on the plate to about -600v thus blocking the lamp. I use a simple interuptor and it works great :) .
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
I guess "second plate" = screen grid?
Marko, turning the MOSFET or triac or whatever off will immediately turn the tube off too. The cathode voltage only rises until the voltage between cathode and grid is enough to stop the tube conducting, which is usually a couple of hundred volts.
Registered Member #89
Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145
EDIT: Now, if I understood this, as cathode voltage rises the screen becomes ''more negative'' to it, and ultimately cuts it off? And chatode-grid capacitance also discharges in process?
Registered Member #160
Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938
Hi there Dr Spark,
Just curious to know how you're going on this project? I know you are into the bipolar marx at the moment, is this because you ran into issues with this project? You can tell me to mind my own business if you want and that it's all in good time. I'm just a curious cat.
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8Kva Quad 833C VTTC
Very nice again. Keep up the good work. Your workshop is so clean too.
