ORIGINAL MESSAGE:
On Fri, 06 Nov 2009 20:44:41 +0000, Mark K5AM <k5am@zianet.com> wrote:
> Even grounded-grid triode
>amplifiers can be configured for this independence; a differential op
>amp circuit can be arranged to measure plate current as
>
> Ib = Ik - Ig
>
>where Ik is cathode current and Ig is grid current.
REPLY:
Yes, it could be done, but that's a lot of work, and I do not trust delicate op
amps in the presence of high voltage and high RF. I would suggest a simpler and
more reliable approach:
Use an SPST relay to open the B- line in each unused amplifier. For safety's
sake, a pair of 6A10 diodes should be connected in anti-parallel from B- to
chassis ground inside the power supply, and another pair likewise inside the
amplifier. The relay would be activated when switching from standby to operate.
Problem solved.
73, Bill W6WRT
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