[Prev][Next][Index][Thread]
Re: tube coils
Tesla List wrote:
>
> >From major-at-vicksburg-dot-comThu Sep 5 22:18:48 1996
> Date: Thu, 05 Sep 1996 18:26:27 -0500
> From: RODERICK MAXWELL <major-at-vicksburg-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: tube coils
>
> I have not even finished my first capacitor discharge tesla coil and already I,m
> looking forward to building a tube driven coil! I've odered a couple of books from
> I.T.S. __Vacuum Tubes In Wireless Communication__ by Elmer E. Bucher ,and __Vacuum Tube
> Tesla Coils__by J.F. Corum and K.L. Corum. I have built several high voltage projects
> using induction coils and a solid state Mosfet driver, but I have never built
> __anything__ that uses tubes.
> In __Vacuum Tubes In Wireless Comunication__ it describes the vacuum tube as a
> rectifier. It also shows the direction of electron flow from the filament to the plate.
> This part I comprehend and understand well. What I have a hard time visualizing is
> current flow from the plate to the filament! If the flow fom the filament to the plate
> is composed of electrons, what is current flow from the plate to the filament composed
> of and what is the mechanism that allows this to happen? Is it simular to hole flow in
> semiconductor material???? Could someone that has experience with tube electronics
> please answer these questions for me so I can sleep nights?
Bingo!
Actually, it's the high voltage on the plate which *attracts* the
electrons from the filament. Current then flows if the grid has a
sufficiently positive charge on it. With a positive grid, the electrons
are 'helped' via attraction to the grid charge, but are pulled all the
way to the plate. When the grid is negative (cutoff), the cathode
(filament) electrons are repulsed, and hang around the cathode in a
small cloud...
Remember - electron movement is from negative to positive, ergo, current
flows OUT of the plate, not the other way around.
- Brent