[Amps] Tetrodes

Peter Chadwick g3rzp at g3rzp.wanadoo.co.uk
Tue Jul 12 10:44:37 EDT 2005


Additionally, some tubes (the old 35T comes to mind) have tantalum anodes.
Tantalum has the property of absorbing gas when it gets hot, unlike most
materials. So tantalum anodes are designed to run hot - in the case of the
35T, so hot that you could see the filament through the plate with the grid
casting a shadow on the plate. 35T's used a special glass called Nonex to
stand the heat.

If you get a plate to screen arc, I don't see how you can have anything
other than negative screen current. Or has Kirchoff been rewritten?

73

Peter G3RZP




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