Hello

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Could you help me validate the attached schematic? The goal is to negatively bias the 3-500Z grid using a Zener diode, without passing the cathode current through the Zener diode.

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The components added to the original schematic are shown in red. The biased wires in the diagram have already been set up in a previous experiment to bake the anodes under low anodic voltage.

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With the original zero bias wiring, I observe, at rest, 250 mA under 2400 V (2x300 W) which seems exaggerated to me.

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I'd like your opinion on this schematic before I do something stupid.

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Could you add to the diagram the diode(s) to be installed in order to limit the effects of an arc which is always possible in a 3-500Z.