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Re: Tube coil capacitors (TV tubes and xrays)



Tesla List wrote:
> 
> Original Poster: bob golding <yubba-at-clara-dot-net>
> 
> At 12:48 17/02/99 -0700, you wrote:
> >Original Poster: "Phillip D. Rembold" <prembold-at-gte-dot-net>
> >
> > If you need a capacitor, ( for either a tube or spark gap coil ) don't
> >have much money to spend, and your project can accommodate the extra room,
> >the quickest source for high voltage capacitors is used TV's. Specifically
> >the CRT - a small 12" monitor has about 0.001 MFD and will hold a voltage
> >around 50 KV, a 24" picture tube reads 0.003 MFD - you can almost double
> >the capacitance by wrapping foil on the outside of any picture tube.
> >
> >I've tried this on both small and medium size coils, it works great !
> 
> hi phillip,
> 
> aren't there going to be copious amounts of x-rays with this set up?
> 
> bob golding
Nope..
1) No hot cathode to emit lots of electrons. In an xray generating tube,
it is the electrons hitting the target at high speed that makes the
xrays. You might get some cold cathode emission of xrays, but I don't
think there would be much.

2) TV Picture tubes are made of thick lead glass, mostly for structural
reasons (the front is a big flat plate that has to resist a lot of force
because of atmospheric pressure: If you have ever tried to deliberately
break the faceplate of a picture tube, you know it is a challenge)

The problems with xrays from color TV's often stemmed from the HV
rectifier tube, not from the picture tube.  
-- 
Jim Lux                               Jet Propulsion Laboratory
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