EXTERNAL: Re: [TCML] Massive VTTC!!!

[Phillip Slawinski]

On Thu, Nov 4, 2010 at 17:45, McCauley, Daniel H <daniel.h.mccauley at lmco.com
> wrote:

> Actually, you are not switching filament to ground.  You are disconnecting
> (interrupting) the Cathode from ground.
> The filament always remains on through the AC transformer.
>
> Dan
>

The cathode in the 833C is directly heated.  In other words the filament
*IS* the cathode.  I'm not actively interrupting the connection of the
cathode to ground.  Supplying current to the gate of the SCR connects it to
ground.  With no power applied to the gate of the SCR the cathode floats.