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>

Tesla list wrote:
 
> Original poster: "Michael Rothberg by way of Terry Fritz
><twftesla-at-qwest-dot-net>" <fishboymichael-at-telocity-dot-com>
 
> 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.
	This happens when the voltage across the ends goes higher
	than the strike voltage.  (say a few hundred volts, varying
	with tube length.)  The Tesla secondary pushes the local
	voltage  to '1000's' of volts/meter, which drives
	the current flow.  The tube can be thought of as part of
	a series circuit, formed by air dielectric capacitors.

	(Experiment:  try larger foil electrodes on the contacts
	of tube.  (hmmmmm useful demo trick anyway....)  This makes
	the 'air capacitor' have a larger value, more current...
	(I believe Tesla used this illustration in his writings.)
	(Fluorescent tubes will ALSO light (same mechanism) under
	HVAC power lines...)

	(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....)

	best
	dwp