Hi Will,
Yes, the grid must always keep its DC connection to ground not to turn into
a runaway condition by a positive charged grid, it does not matter whether
it is grounded grid or grounded cathode circuitry.
For that reason VALVO suggested the 50KOhm safety resistor from grid to
ground in their transmitting tube manual when the grid is not strapped to
ground.
73
Peter
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
Behalf Of Will Matney
Sent: Dienstag, 25. Juli 2006 20:52
To: amps@contesting.com
Subject: Re: [Amps] Fw: "Tubes 201" - How Vacuum Tubes Really Work
Peter,
Thanks! That is the very point I have been trying to get across all along!
Remember, the original threads were asking about a 3-500Z with the grid
resistor or fuse in G-G., or it was when I jumped in the mix There's been a
lot of other tubes and circuits dragged into the discussion, but I've tried
to center my comments around a 3-500Z G-G circuit. In grid driven circuits
though as in receivers and transmitters, or some amps, the grid can be made
to go positive for part of a cycle. This I think Rich means also. He can
correct me if I'm wrong.
Thanks,
Will
*********** REPLY SEPARATOR ***********
On 7/25/06 at 8:40 PM Peter Voelpel wrote:
>Hi Will,
>
>when the grid is kept grounded it can not become more positive then the
>cathode if that is grounded and not negative biased as well, except by RF
>drive on it above its choke.
>
>73
>Peter
>
>-----Original Message-----
>From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
>Behalf Of Will Matney
>
>Peter,
>
>On that, I agree it's the only way to make one positive (for only part of a
>cycle). Are there any other ways to make the grid positive and the grid be
>at ground potential with the cathode at ground? A lot of amps cathodes are
>at ground potential unless biased.
>
>Best,
>
>Will
>
>
>
>*********** REPLY SEPARATOR ***********
>
>On 7/25/06 at 8:04 PM Peter Voelpel wrote:
>
>>Nothing is easier then that if the cathode is going/driven negative with
>>respect to ground.
>>Grid voltage is always measured from grid to cathode, not to ground.
>>
>>73
>>Peter
>>
>>
>>-----Original Message-----
>>From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
>>Behalf Of Will Matney
>>
>>please explain how a grid becomes positive when tied to ground?
>>
>>
>>
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>
>
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