Re: fluorescent tube question

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "marc metlicka by way of Terry Fritz <twftesla-at-qwest-dot-net>" <mystuffs-at-orwell-dot-net>



Tesla list wrote:
> 
> Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<jimlux-at-earthlink-dot-net>
> 
> The electric field is high enough to ionize some of the mercury vapor
> inside the tube, which then emits UV and makes the phosphor glow.  You
> don't need much field... a few hundred V/m is enough to get it going.
> Considering that the field near the TC is probably around 100-200 kV/meter,
> you can be pretty far away and still have the few hundred.  A program like
> Etesla will show you the relative field strength as a function of distance,
> and you could probably use it to figure how far you can get and still light
> up the tube.

Cool data, much learning here!


> Your hand and body can act as a capacitively coupled antenna and increase
> the field somewhat to get it to glow better.

I wonder weather it is that you make a better return path, or a better
static receptor?


> 
> Watch out when doing this that you don't get a streamer to one end of the
> tube while you hold the other.  The tube is a reasonable conductor for a
> direct strike, and you WILL get shocked.  (First hand personal experience
> here....)

OOOH, my buddy holding one end to his groin, Always make me shiver!!


> 
> Neon signs will also light up, but in my limited experience, it takes more
> field to get them to glow.... probably some geometry and gas pressure
> effect...


I was given a six foot length of red sign tubing, I have found that the
"glow" seems to stop at certain points were the field strength must fall
of? It can be moved around a source like a vttc or disruptive, and at a
circular point around the parameter, a field strength can be seen?

  after all, neon signs need many kV to "strike" (hence the NST at
> 15 kV).. Fluorescent ballasts only kick out 500 or so volts to start a 8
> foot long tube.

Good point! But the fluorescent tubes conduct better at close range. The
glass is "REAL" thin, arcs pierce neon very rarely.


Marc M.