In Reply to: Something I don't Understand... posted by Lee of Omaha on November 11, 2014 at 15:13:18:
The inside of the cathode sleeve is NOT coated, and is a poor emitter. But either electrode will still emit enough electrons to the other positive electrode.
Because the emission is poor, this thermionic diode is easily saturated. At typically 30v or more difference either way, the leakage current is saturated and does not vary with the heater instantaneous voltage - the voltage fluctuations can't cause a hum because the current does not fluctuate.
Of course there is still capacitive coupling between the electrodes ...
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Follow Ups
- RE: Something I don't Understand... - Paul Joppa 21:54:56 11/11/14 (4)
- RE: Something I don't Understand... - Alex Kitic 00:24:06 11/12/14 (3)
- RE: Something I don't Understand... - Stuben 12:44:06 11/12/14 (1)
- RE: Something I don't Understand... - Stuben 12:52:59 11/12/14 (0)
- Riddle me this... - SteveBrown 08:04:29 11/12/14 (0)