>>If the tube is not gassy, and the grid is floating, the
>>electron
>>stream from the cathode probably raises the grid-cathode
>>(fil-CT)
>>potential to a few volts negative
So if it doesn't matter, why do tube manufacturers specify a maximum grid -
cathode resistance for a lot of tubes? Even low power audio tubes used in Class
A?
My experience is that exceeding the the maximum grid-cathode resistance can
(but not always does) lead to a plate current runaway, even in tubes with no
measurable gas (as measured by grid current)
73
Peter G3RZP
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