[Amps] 813 cathode zener bias

[Bill, W6WRT]

ORIGINAL MESSAGE:

On Mon, 25 May 2009 05:09:43 -0600, "Steve Flood" <kk7uv at bresnan.net>
wrote:

>Without any published tube charts for 813 g-g operation,  how much cathode bias voltage range do I need if I wish to experiment with AB, B, and C operation?

REPLY:

When reading the characteristic curves chart, it doesn't matter
whether the tube is operated in GG or 'normal'. Just select the plate
voltage and the desired idling current and read across to get the
bias. 

In terms of grid bias when the tube is idling, it doesn't know or care
whether the circuit is grounded grid or 'normal'. Just provide the
correct bias for a given plate voltage and you'll get the desired idle
current.

73, Bill W6WRT