Re: Understanding Vacuum Tube Diagrams?

[EMAIL PROTECTED] (tiger x) wrote in message news:<[EMAIL PROTECTED]>...
> "Chris Cooper" <[EMAIL PROTECTED]> wrote in message news:<[EMAIL PROTECTED]>...
> > I've got an old wire record I'm trying to revive (see my "Reviving 50+ year
> > old Wire Recorder" post), one of the problems is that I don't quite
> > understand how to interpret the schematics for the vacuum tubes.  Is there a
> > simple explanation (online preferably) that talks about the "standard
> > symbols" used in vacuum tube internals?
> > 
> > Thanks!
> > Chris
> 
> A real simple explaination of vacuum tubes:
> 1. The source of electrons is the cathode.
> 2. To release electrons, the cathode must be heated by the filament.
> 3. Released electrons must be attracted & gathered up by the plate.
> 4. The flow of electrons through the tube is regulated by the control
> grid.
> 5. Any other grids in the tube are for effecient operation of the
> tube.
> 6. The cathode has a negative potential.
> 7. The plate has a positive potential.
> 8. The control grid potential varies according to the input signal.
> 9. On a schematic, the control grid is the bottom grid and enters on
> the left of the tube.
> 10. The signal out of the tube usually leaves via the plate (top), but
> may leave via a resistor connected to the cathode (bottom).
> 
> Easy as that!
> 
> Tiger


Man you must be a young buck not to know about vacuum tubes ;) or i'm
just
an old #art. Wet behind the ears but interested in 50 year old vintage
electronic devices, all right then. 
I know this is a late response but ...
Vacuum tubes share a lot of similarity to Depletion mode MOSFETs in
terms of the design equations. Mind you tubes require much higher DC
operating voltages plus the aformentioned filament juice.
Source Gate Drain are analagous to Cathode Grid Plate.

MENO