Path: utzoo!attcan!uunet!samsung!munnari.oz.au!murtoa.cs.mu.oz.au!ditmela!latcs1!mahler
From: mahler@latcs1.oz.au (Daniel Mahler)
Newsgroups: sci.electronics
Subject: Re: funny phosphorus illumination after power to tv has been turned off
Message-ID: <7101@latcs1.oz.au>
Date: 13 Jan 90 20:11:58 GMT
References: <6805@lindy.Stanford.EDU>
Reply-To: mahler@latcs1.oz (Daniel Mahler)
Organization: Comp Sci, La Trobe Uni, Australia
Lines: 34

In article <6805@lindy.Stanford.EDU> you write:
>
>When I turn my TV off, areas around the center of the screen dance around
>brightly in multicolored flames. It is quite pretty but I can't seem to
>explain it. Unplugging the set has no effect. It still continues for
>about 10 minutes before dying out. Now this is an active flaming that
>changes shape and color quite rapidly.

     Well, how about this: A static charge builds up on the front of the
tube while the set is on. To prove this, just run your hand over the screen
just after you've switched it off - you'll hear the crackling as it
discharges to your hand (there's not enough there to hurt you - I have done
this frequently before.) Once the set is switched off, the charge on the
front of the tube leaks (through the screen front? This seems most likely
to explain the phenomenon you describe) until it's discharged completely,
and its energy is displayed to you in the form of a light show. Note that
this doesn't depend on geographic location, the set being plugged in,
radiation being nearby (which would provide a constant glow, not one that
only lasts 10 minutes), or indeed anything other than that the set have
been on recently. Incidently, running your hand over the screen is
harmless because the charge you're conducting is only from a small part
of the screen - the rest of the screen won't discharge because glass is
such a good insulator (which incidentally is the reason the charge is
held so well.) Don't (as I tried one day) cut a lump of foil, cover the
screen, and discharge through that. (The things we do for knowledge...)
This may not be the real cause of the phenomenon, but it's easily tested
- just run your hand over the screen after you turn it off. If the effect
goes away, this is the reason.


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