Here's another little mystery regarding Neon lamps:

I have sometimes taken a Neon-bulb based AC voltage tester and only plugged
the one lead into the hot side and left the other side floating in the air.
What I observed was a dim glow only near ONE of the two electrodes. My
guess is that what is happening is that the glow is only emitted where
electrons are hitting an electrode inside the lamp, and that this actually
indicates that a small current is flowing in only one direction through the
lamp. Possibly the lead floating in the air has a rectifying effect due to
there being more cations than anions (or vice versa) in the air?

Any ideas?

What does a Neon bulb normally do when connected to DC (I didn't think to
try it until just now, but I don't have one handy)? Does only one electrode
glow?

Sean

At 09:40 PM 11/25/99 -0600, you wrote:
>I've read that the older high quality neon lamps had a small chunk of
>radioactive material near the envelope (perhaps inside?) to partially
>ionize the neon gas.  Probably made the lamps easier to start and more
>reliable, especially in low ambient light situations.  Wonder if anyone
>still builds 'em like that.
>
>I've also read about troubleshooting difficulties with some of the old Tek
>scopes that used gas-discharge regulator tubes.  Scopes wouldn't work
>right, until the tech removed the covers.  Once exposed to ambient light,
>everything would fall into place.  I'm sure that could be a real bear to
>track down the first time you run into it...
>
>Some of my power strips have flickering neons too.
>
>
>newell
>
|
| Sean Breheny
| Amateur Radio Callsign: KA3YXM
| Electrical Engineering Student
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