Re: Why does this neon flicker?

From: Andy Cowley (andy.cowley_at_uwe.ac.uk)
Date: 09/28/04 

Date: Tue, 28 Sep 2004 11:09:15 GMT

John Fields wrote:

> Andy Cowley wrote :
>> The thermal/convection one, which seems in part what you
>> suggest, will be investigated tonight and I'll post the results.
>> .....
>> Check out the updated web page and then see if your explanation still
>> holds.
>
> It does until you prove otherwise, and I'll be looking forward to
> reading about the methodology of your investigation. :-)

A very simplistic methodology, I'm afraid. I operated the bulb in three
mutually perpendicular orientations. The result was that it made no
difference at all to the areas glowing or to the flicker rate. I conclude
that convection in the gas is not the cause of the flicker.

>
> BTW, since you asked about the behavior of the lamps under AC
> conditions, your DC data is meaningless, since the continuous cycle of
> voltage rising to a strike followed by settling into a "valley", then
> later deionization followed by another strike... doesn't happen with
> DC excitation.

I didn't ask about the behaviour of lamps under AC conditions, I asked why
the neon flickered. See the thread title. I gave the conditions under which
I had observed the flickering. As it turns out the neon flickers
under DC or AC conditions. My DC data is not, IMHO, meaningless, as it shows
that any explanation relying on AC conditions is incorrect. Check
http://zen.uwe.ac.uk/neon/neon.html where you will be able to see the
tube flickering under various DC conditions.

>
> If I meant 'arc' I'd have written "arc", and I believe a glow
> discharge is, in effect, a plasma, which is why I wrote "plasma".

You wrote :-

"the ionization potential gets to be too high to maintain the arc."

which is why I thought you were referring to an arc. An easy mistake
to make. ;-)

best

Andy