Re: Van der Pol

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Mddeming@xxxxxxx 

Hi Ed,

I don't have a schematic at hand right now, but as I remember it was 
a coil-less oscillator that operated because at a certain ratio of 
voltages between the grids the tube goes into a "negative resistance" 
region where increasing current causes decreasing voltage, then at a 
certain point switches back to positive slope causing oscillation. I 
think there was also a circuit in my dad's "Fundamentals of Radio", 
(Jordan et al c.1942) and there was a Federal Telephone & Radio 
reference book from the same era that had a schematic but no 
explaining text, IIRC.

Matt D.


In a message dated 12/14/05 7:46:57 P.M. Eastern Standard Time, 
tesla@xxxxxxxxxx writes:

Tesla list wrote:

>Original poster: Mddeming@xxxxxxx
>Hi All,
>
>     Is anyone left who is:
>
>1) Old enough to remember the Tetrode-based Van der Pol Oscillator
>  and
>2) Young enough to remember what they knew  ;-))
>  and
>3) Knows if it has any application to a VTTC?
>
>Thanks,
>
>Matt D.

  I'm old enough and I'm certainly aware of who van der Pol was,
but never heard of this particular circuit. Do you have a schematic
or a reference to where one can be found?  I can't imagine it has
much to offer compared to a simple triode oscillator.

Ed