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Using X-rays to Measure Tesla Coil Voltage
From: Thomas McGahee[SMTP:tom_mcgahee-at-sigmais-dot-com]
Sent: Tuesday, September 23, 1997 8:26 AM
To: Tesla List
Subject: Using X-rays to Measure Tesla Coil Voltage
>
> From: Greg Leyh[SMTP:lod-at-pacbell-dot-net]
> Sent: Monday, September 22, 1997 5:25 PM
> To: Tesla List
> Subject: Re: Secondary voltage measurement.
>
> DR.RESONANCE wrote:
>
>
> > The unit was our standard model M-150 running with a 14.4 kV pole
xmfr as
> > the power source. As to the measurement equipment, well, lets
just say I
> > have some friends at a local university who "borrowed"
(unofficially of
> > course --- and for only a 4 day period) some unique test
equipment from a
> > well equipped physics dept and they took the measurements. Can't
say much
> > more without shooting myself in the foot in case I might need
some more
> > equipment for short term use in the future.
>
> Can you at least mention the general principle behind the
measurement?
>
> -GL
>
>
Greg,
When I was in high school in the mid 1960's I built (among other
things) a number of homemade x-ray machines. These ranged all the way
from 40KV to 250KV units. The intensity of the x-rays produced was a
function of current. The penetrating ability of the x-rays was a
function of voltage. I was able to "calibrate" my machines through
the use of a set of stepped wedges that were made of strips of
aluminum and steel. The higher the KV, the greater the thickness
through which the x-rays could penetrate. I was able to get the
radiology department of the local hospital to x-ray my step wedge in
25KV increments. Then I used the negatives to calibrate my step
wedge.
No matter how long an exposure I used, I could not get a 100KV unit
to expose past the 100KV step on the calibration film. The method was
quite effective. An intensifier screen could be used to reduce the
exposure *time*, but the penetration level would be unaffected by the
use of the screen.
Instead of using film, I could have used a radiation detector such as
a scintillation detector to determine the penetration depth in real
time. Of course, such equipment might have barfed at the Radio
Frequency fields that emanated from my apparatus (They were Tesla and
Oudin coils, of course), but good old x-ray film is unperturbed by
such things. Cheap and effective!
Dr. Resonance may have been using a similar approach to measure the
voltage of his Tesla coil. Or he may have been using some totally
different and more esoteric approach. The bottom line, though, is
that the use of x-ray penetrating ability is a very valid way to
measure extremely high voltages. Also note that any voltage thus
measured is actually a voltage that was measured under a certain
amount of loading. If x-ray penetration says you got 1 MV, then you
can absolutely believe it as being true.
Hope this helps.
Fr. Tom McGahee