Separate B-minus connection is not necessary.
A high voltage power supply should be usable with
any amplifier having demands within its capabilities; a restrictive
one-to-one amplifier-supply correspondence is undesirable. A single-
operator station can have several amplifiers simultaneously
connected to a single high voltage power supply; each amplifier
draws current only when it is transmitting. This idea is no more
complicated than having several items connected to one 13.6 VDC
power supply, or several lamps connected to one household circuit.
Each amplifier on line may have full internal metering, contain
its own filament, bias, screen, and control power supplies, and require no
separate B-minus connection to the power supply.
The B-minus lead from the rectifier in the power supply should run
directly through a metering shunt to ground. A special B-minus
connection to an amplifier for metering purposes is inconvenient,
unnecessary, and potentially unsafe. 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.
More details:
Download "Overload Protecton for High Voltage Power Supplies"
at www.zianet.com/k5am/
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