Re: fluorescent tube question

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

Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>" <davep-at-quik-dot-com>

Hi Dave:
(we gonna get someone confused...  8)>>)

Tesla list wrote:
 
> Original poster: "David Thomson by way of Terry Fritz
><twftesla-at-qwest-dot-net>" <dave-at-volantis-dot-org>
 
> Hi Dave,
 
> > How does the output of a tesla coil light a fluorescent tube from a
> > distance without direct contact?
 
>         The tube lights, largely, from current flows thru the tube.
 
> Not quite.

	cf any text on fluorescents.  The description is exact.
  
> Tesla coils work at very high voltages,

	Thanks.  I'm aware of that.

> therefore the current is quite low.

	If powers are low.  If powers are substantial, and during
	'strikes', currents can be quite high.

> It's the high energy state of the voltage and charge that excites the
> mercury and other gasses within the tube and causes photo
> phosphorescence.

	Possibly.  I suggest this is to be verified by careful
	experiment.  Thus i proposed adding 'capacity areas'
	to the terminals.  If these increase light output
	then at least some of the light is from current,
	as i outlined.  (cf also, below)

	I suggest further that the 'excitation of the electrons'
	(one step further down the explanation than i went) is
	due to current flow: either direct to the gas (which
	i alluded to below) or via the normal electrodes.
	My suspicion is that the glow via the electrodes is
	the major source.  In either case, the current is driven
	(as i noted) by the voltages present on the Tesla secondary
	system.

	There may well be lighting due to multiple effects.

>         (Question:
>         Is there any lighting due to 'direct' excitation of the
>         phosphors?  Tricky experiment to do....   Hmmmmm.  Use
>         loose CRT instead of a fluorescent tube?  Caution with the
>         loose CRT....)
 
> I've been thinking about using a loose CRT, too.  Tesla did many
> experiments in this manner.

	None, i think, with the equivalent of a modern CRT.
	Note that when he did such, he commonly added capacity
	areas to the ends of the devices.  In some cases (eg:
	lighting incandescents), this clearly showed current
	transfer.

	cf 'Experiments with Alternate Currents of High Potential
	and High Frequency, N Tesla.  (I think that's pretty close to
	the title...)
	
> Like you said, anybody considering this experiment should be very
> careful.  With high enough energy input into a CRT, strong X-rays
> can be produced.

	Possible, I would be more concerned about breaking the
	CRT.  This scatters a LOT of glass VERY vigorously.
	(been there, done that, controlled circumstances...
	I'm thinking of dropped CRTs rather than electrical