vac tubes / was Re: Schematics of Atanasoff-Berry

Chuck Guzis cclist at
Fri Sep 5 17:00:38 CDT 2008

On 5 Sep 2008 at 22:12, Pete Turnbull wrote:

> I don't think so, or at least not very different (I didn't actually 
> measure it).  I've got a couple here, salvaged from flashguns that had 
> one red/orange neon and one green one.  They look the same, except for 
> the band of phosphor at one end of the green ones, and ran off the same 
> voltage.  The green ones aren't completely covered with phosphor inside, 
> and it's possible to see the usual orange glow when you look in the end 
> with the wires, too.  I must go and find a diffraction grating -- I know 
> I've got one here somewhere...

Here's a chart from a manufacturer:

The specturm of neon:

Apparently there's enough UV from the discharge to excite a phosphor.

These all seem to be close enough in ratings from color to color 
(given the same size of lamp) to lead me to believe they all have the 
tranditional Penning mixture of 99.5% neon and 0.5% argon. 


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