[Amps] Zener Screen Regulators

[Bill, W6WRT]

ORIGINAL MESSAGE: 
On Tue, 4 Sep 2012 20:12:58 -0600, Jim wrote:

>So my advice, which you're free to ignore (but unwise to do so), is to get
>used to the century-old sign convention. In an RF amplifier, the plate
>current flows out of the positive terminal of the power supply, into the
>plate of the tube, down to the cathode, and back into the negative terminal
>of the power supply. Anything that sources current has current flowing out
>of it. Anything that sinks current has current flowing into it. The sign of
>the charge carriers is immaterial to this view.

REPLY: 
Psychologists call this denial. 

I still ask for an explanation of why the filament or cathode in a tube has to
be heated to receive the current flow. I've been asking this question for fifty
years. Still waiting. 

73, Bill W6WRT