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Re: Conducting through glass
to: Andy
The glass essentially forms a high voltage capacitor. A rather different
type of current flows through the dielectric -- known as "displacement
current". Any good modern physics college textbook will have a description
of displacement current.
Regards,
Dr. Resonance
-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Sunday, February 20, 2000 12:54 AM
Subject: Re: Conducting through glass
Original Poster: "Reinhard Walter Buchner" <rw.buchner-at-verbund-dot-net>
Hi Andy,
>Original Poster: "Andy Cleary" <gemware2-at-dreamscape-dot-com>
> I am curious, why is the HV output of a Tesla Coil (or I'd
>assume any other HV source) able to go through a thin piece
>of glass, without a sign ofdamage? I thought glass would
>insulate it, or can the electricity flow through thin layers of it?
snip
You have read the comments to your post. I would now like to
add that glass can indeed conduct electricity. If you place a
piece of glass (tubing or thin solid rod works best) between the
electrodes of a HV xformer and heat the glass to a bright red-
orange (with an external flame or the HV discharge itself), it will
start to conduct and glow on its own. In (semi)fluid state, glass
will allow ions to migrate from one end to the other resulting in
a high (kohms) ohm resistor. This gets very hot from the I^2*R
losses. However, it is kind of interesting to see a light bulb
"filament" made out of glass. You can do something similar in a
µwave oven (off topic). However be careful, if you try this or the
above. Don´t use a hand held propane torch to heat the glass
(because of the obvious shock hazards). It won´t work with the
output from a TC, because the current isn´t high enough.
Coiler greets from Germany,
Reinhard