Will writes:
> Joe, your not compairing apples to apples here. Your
> compairing a vary large capacitor to a piece of wire about a
> foot long (if that) when its straightened out. I've never
> seen the grid in a tube charge up by setting on the shelf.
> Also, the re-charging of the large capacitor is caused by
> something else all together different than what's in question.
You're the one who raised the capacitor issue:
>> That would be like a capacitor charging up with only
>> one lead connected to a power supply, and the other lead left
>> un-connected. It can do it before the fuse blows, but not
>> afterwards, there's just no path for it to work.
The grid can and will become positive in the presence of an
electrode stream and voltages on the other electrodes. A screen
will certainly go to full anode potential and destroy the tube
if disconnected with B+ applied. If it is hot (from either
excess grid current, electron bombardment or anode to grid arc)
a control grid will certainly climb high enough that it can arc
to the cathode or filament. These are totally different than a
tube setting on the shelf or setting in circuit without filament
power or B+ applied.
73,
... Joe, W4TV
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