In ,
George Herold wrote:

On Mar 1, 5:48*pm, (Don Klipstein) wrote:
In ,
George Herold wrote:

SNIP to here

Yes the lamp looks like the picture in the wiki article. * If I
believe the curve there, then I've got something like 160-200 volts
across the lamp at 20mA. *So I've got (call it) 80 V to drop on the
resistor at 20mA.. I get 3 k ohm at a watt or two. *Hmm maybe what
looks like brown black brown is a discolored red black red. *(I always
have hated the way red and brown look almost the same on the pale blue
body of the metal film resistors.)

100k seems like it won't allow enough current through to keep the lmap
lite. *(But I've never worked with neon lamps.)

* I don't believe the voltages in that curve in Wiki - I would plan on 70
volts and peak current around 3 milliamps (peak voltage of 240 VAC is
about 340 volts).

* If the glass bulb's overall length is 3/4 inch, then the neon lamp is
probably an NE-2H. I would use an 82K or 100K 2-watt resistor for an
NE-2H at 240 volts AC. I would err on the high side (100K) to maximize
life of the lamp. *I suspect the toated resistor is a 100K 2 watt whose
yellow band was browned by being toasted.

Excellent, Thanks Don. I like the faded yellow stripe idea. The bulb
is about 1/2 that size. It's standing straight up and the tip of the
glass is 0.4" (10mm) above the circuit board.

That sounds just a little small for the A1B (mini NE-2) and the A1C
(mini NE-2H), so I suspect your lamp is one of those. Given the size of
the resistor, I think it's the latter.

If your neon lamp kicked the bucket along with the resistor (more likely
it survived, at least well enough to glow from 240 volts AC), Radio Shack
may still carry these (a litle incorrectly calling them NE-2H).

- Don Klipstein )