Re: [TCML] Rectifying a Tesla coil

[Frank <fxrays@xxxxxxxxxx>]

Hi Kurt,
Very nice find, I have been after one of those tubes for years!
If you even want to part with it, drop me a line.

It is actually not a "true" rectifier in that it was used with an 
induction coil, which is pulsating DC, to block the inverse voltage 
on larger coils. Typically it was used with coils of 12" spark 
capability or larger as the inverse became significant and damaged 
the X ray tube.

They were of limited use before the vacuum level had to be adjusted.

The apple green glow you see in at the cathode in your operating pix 
is soft X rays being produced.

The geometry of the tube made a high resistance in one direction of 
current and a low resistance in the other. It still had a significant 
voltage drop when conducting and was for 5-10 ma currents!

It is not really a high frequency tube either, operating frequencies 
were around 2000-5000 Hz.

Again, nice pix!

I would not recommend you continue to use it on your TC tho as it 
will damage it, especially if you draw an arc from it.

Frank

At 06:11 PM 8/31/2008 +0200, you wrote:
> Hi,
>
> A cold elecrode tube device, essentially based on the "point and 
> plate" principle, is called "Villard Valve", see:
>
> http://danielgiroux.neuf.fr/page304.htm
>
> By good luck I was getting hold of a nice specimen:
>
> http://home.datacomm.ch/m.schraner/Villard0696k.jpg
> http://home.datacomm.ch/m.schraner/Villard0699k.jpg
>
> I tested it, and the tube is working fine:
> http://home.datacomm.ch/m.schraner/Villard0700k.jpg
>
> However I don't operate it for extended time, in order to avoid 
> exposure to the unknown amount of X-Rax radiation. (Didn't yet try 
> to charge a capacitive device).
>
> Regards,
> Kurt
>
> Sfxneon@xxxxxxx wrote:
> > In a message dated 8/29/2008 1:52:22 P.M. Central Daylight Time,
> > jhowson4@xxxxxxxxxxx writes:
> >
> > > Is it possible to rectifiy a Huge tesla coil?
> > > No reason I  was just curious.
> >
> > A simple, but not too efficient method to rectify the output of a
> > _large_
> > coil might be the "point and plate electrode" type of rectifier where
> > a pointed metal rod is aimed at the center of a round metal plate,
> > close enough for ionization to take place. Some rectifying action
> > takes place due to the geometry of the electrodes, and a high DC
> > potential can be accumulated. I'll bet
> > Jeff at Electrotherapy Museum has some examples of this being used
> > for early x-ray tubes, huh Jeff?
> >
> > Tony Greer
>
>
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