[Amps] grid fuses

[Bill Turner]

ORIGINAL MESSAGE:

On Fri, 21 Jul 2006 02:30:16 -0400, Will wrote:


>How can it collect electrons from the cathode and take a charge when the path back to the cathode is broken via a blown fuse between the grid and ground making an open circuit? 

------------ REPLY SEPARATOR ------------

Stray electrons within the tube can attach themselves to the floating
grid and develop a small charge, typically no more than a few volts.
To prove this to yourself, set up a tube with only filament/heater
voltage applied and measure the c-g voltage with a high impedance
meter. You will be amazed.

In the case of small receiving tubes, this charge can actually be used
to bias the tube when operated class A, although this is not really
good design because of variation between tubes. It's just an
interesting experiment.

Bill, W6WRT