Re: Magnifier system

To: tesla-at-pupman-dot-com
Subject: Re: Magnifier system
From: Bert Hickman <bert.hickman-at-aquila-dot-com>
Date: Thu, 21 Nov 1996 20:49:35 -0800
Tesla List wrote:
> 
> >From MALCOLM-at-directorate.wnp.ac.nzThu Nov 21 14:43:07 1996
> Date: Fri, 22 Nov 1996 08:54:46 +1200
> From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
> To: tesla-at-pupman-dot-com
> Subject: Re: Magnifier system
> 
> Hi Bert,
> > >
> > >   I limit resistor
> > >   ----\/\/\/------+--->  <-------OOOOOOOOOO)
> > >                   |    gap         resonator
> > > from              |
> > > DC supply         |
> > >                -------  very large cap (low-Z drive for resonator)
> > >                -------
> > >                   |
> > >    ---------------|
> > >                 ground
> > >
> > > To be tried out of interest,
> > > Malcolm
> >
> > Malcolm,
> >
> > Thanks! What behavior are you expecting from this configuration? I could
> > envision up to 2 x DC Supply swings on the output, but that's about it.
> > Now if you drove it from a low Z AC source at the resonator's Fo,
> > Shazaam!
> >
> > -- Bert --
> 
> Nothing out of the ordinary really/ It just seemed like an
> interesting idea to try - sort cap - tx line - cap direct coupled.
> You'd have to be really careful about using an ordinary AC supply
> at amins frequency because of the non-isolation (to the new blood:
> this is a lethal configuration!!!)  Running it from a hi-f power
> oscillator is no different from a standar extra coil configuration
> (a la Duane Byland et al).
> 
> Malcolm

Hi Malcolm!

Thanks! Reason I asked, I was recently reviewing "The Theory of Gaseous
Conduction and Electronics", by Frederick A. Maxfield and R. Ralph
Benedict, McGraw Hill, 1941, where a number of glow and arc oscillators
are described. In addition to the intermittent arc oscillators that many
of us know and love (hate?), a couple of other arc oscillators are also
discussed. These take advantage of the negative resistance
characteristic of an active arc to produce sustained oscillations. 


                 Lo                  R

     ---------()()()()-----------/\/\/\/\------
     |                     |                  |
     |                     |                  |  
                           0  Gap           ===== C
     Vin                   0                ===== 
                           |                  |
     |                     |        L         |
     |                     |                  |
     ----------------------------()()()()------   

An arc was struck across the gap, and was stabilized through ballast
inductor Lo. The effect of the negative arc characteristic was to create
_non-damped_ oscillations with a frequency of about 1/(2*PI*SQRT(LC)).
In air, the dynamic arc characteristics limited the frequency to about
5-10 kHz. However, frequencies of up to 100 kHz were achieved by using a
hydrogen atmosphere and very large magnets (some up to 50 - 100 tons!)
to create a very strong transverse magnetic field to destabilize and
help deionize the arc. These "Poulsen Arc Generators" had efficiencies
of as much as 40-50%. They were eventually replaced by more efficient
high power vacuum tubes. 

An interesting note: many of the larger Poulsen Arc magnets eventually
found re-use in nuclear research as cyclotron magnets. Seems like
researchers and experimenters have _always_ scrounged for wierder stuff!

Anyways... Safe coilin' to ya!

-- Bert --