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: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Esondrmn-at-aol-dot-com>

> In a message dated 3/25/02 11:50:27 AM Pacific Standard Time,
tesla-at-pupman-dot-com
> writes:

> > From: Tesla list [mailto:tesla-at-pupman-dot-com]
> > > Sent: Sunday, March 24, 2002 3:19 PM
> > > To: tesla-at-pupman-dot-com
> > > Subject: Re: fluorescent tube question

> > > Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> > > <evp-at-pacbell-dot-net>

> > > Some of the posts here seem to overlook the fact that current must flow
> > > through the tube to ionize the mercury vapor/gas fill and excite it into
> > > generating UV light.  Since there is a voltage drop across the tube that
> > > means power must flow.

> > > Ed
 
>I always thought (maybe incorrectly) that the RF from the Tesla coil
> was exciting the phosphor on the inside of the tube directly and not
> ionizing the gas in the tube.
 
> Ed Sonderman

	My point, if poorly made, is that there are multiple ways 
	to excite the phosphor:

		Normally, the tube uses current to ionize the gas,
		driven by relatively low voltage (ca 40-50vrms).

		However, until the experiment is done, there are
		other possibilities, notably that the highish e field
		ionizes the Hg vapour (what little there is, when
		cold), or the other gases (Argon?) in the tube, or
		the efield activates the phosphor directly, in some
		fashion.

	Or, at least as likely, some combination of these.  Offhand:
	If adding capacity areas to the ends increases the light,
	likely a current flow effect thru the tube, at least in part,
	capacitive coupled.

	If not, if trying a 'tight faraday cage' around the tube (tin
	foil, screen wire) reduces the glow, likely direct coupling,	
	either to phosphor or via ionizing the gas (es).

	(Interpreting faraday cage results can be tricky, as they
	can leak, unless well done...)

	best
	dwp