Blind Angel - 28-7-2007 at 09:39
We currently have 2 box full of old AA Hollow Cathode lamp, most of them were retrieve from old mine laboratory and bought in bulk lot, untested. We
are testing them, most of them light up when plug, some don't. Can we consider the one that light up to be good enough to be put on eBay, or further
testing would be neccessary to be sure that they work and are efficient. Most of them still are in their original box with the original warranty
paper. Anybody could help.
Also I was planning to try to sell the working one for around 100$ each on eBay, is that too much or not enough?
I'll post the one that work here if anybody is also interested.
Edit: Some of them are dated between 1995-1998 so it's a safe bet to say that the lot is around ~10 years old
[Edited on 28-7-2007 by Blind Angel]
12AX7 - 28-7-2007 at 09:51
Do hollow cathode lamps *always* glow in visible light? There are plenty of elements that have spectral lines outside of the visible range.
Tim
Blind Angel - 28-7-2007 at 09:59
Some have the mention UV light on them but they still have a red glow in the visible spectrum, probably due to the heating of the element.
12AX7 - 28-7-2007 at 10:14
Ah yes, filament cathode. Well obviously, the ones that don't heat up are completely kaput -- no filament glow, no emission.
Blind Angel - 28-7-2007 at 10:22
From what I see it's not the filament that is glowing though. It seem to be the space between two metal piece. To be honest, I don't really know
anything about this lamp since I never used them nor had a course on them. I'm currently looking for info.
Edit: http://en.wikipedia.org/wiki/Hollow_cathode_lamp this is what I have.
[Edited on 28-7-2007 by Blind Angel]
12AX7 - 28-7-2007 at 10:35
Oh, well a glow discharge of a noble gas should always be something. Does the cathode ever run out of hollow-ness, so to speak?
Being glow lamps, they should always glow when enough voltage is applied.
Do any of them have a shiny "getter" spot on the glass? If it's oxidized (white), it must be leaky. I don't know if those usually have getters.
I don't know if it would damage them, hooking up to a neon sign transformer to see if a whole lot of voltage does something. Certainly, a thin blue
spark that looks like air would be a bad sign.
Tim
Blind Angel - 28-7-2007 at 10:43
Most of them have a Shiny spot, some have a black burnt style spot. None of the glowing one seem cracked. I think that I could safely list them as
working since I don't see how they could emit a different spectrum.
Ozone - 29-7-2007 at 06:21
IIRC, some HC's have a shelf-life! This depends on the element (some, never run and stored for a long time might be shot). I'm not too sure that
glowing=absolutely good. The only real test would be to look at the actual spectral output.
Cheers,
O3