> From: "Ian White, G3SEK" <G3SEK@ifwtech.demon.co.uk>
> Subject: Re: [AMPS] L-4B grid ckt shorts
To: <amps@contesting.com>
> Date: Sun, 21 Sep 97 21:49:35 +0000
> The same conclusion still applies, though. It seems incredible that so
> much grid current could be flowing in an oscillation condition. I mean,
> if that was the grid current, how big would the cathode current have to
> be... and where would it come from?
That's a good question Ian, since even 2000 volts of positive grid
and anode voltage wouldn't drive that much current through the tube.
The peak emission current of an ideally constructed thoriated
tungsten filament tube is just over 100 mA per watt of filament
power.
15 amperes at 5 volts is 75 watts. 75 watts times 100 mA is is 7.5
amperes.
It's obviously not oscillations.
73, Tom W8JI
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