NE2

I looked in my PDF copy of "GE Glow Lamps" copyright 1965 and it sez:

"The NE-23 is a modification of the NE-2 indicator lap with mild radioactive additive for the reduction of dark effect. Both its low cost and stable characteristics following aging account for its popularity."

I have had experience with NE-51 (IIRC?), bayonet base neon lamp, KR-85- additive version.

Something else: My experience is that "standard intensity" neon lamps in general don't have trouble starting at 110-120 volts AC. It appears to me that radioactive additives are needed to achieve reliable starting at lower voltages, maybe ~100-110 volts *peak*.

"Standard intensity" neon lamps include the "true NE-2" (A1A) and the "mini true NE-2" (A1B). They appear to me to contain a 99.5% neon, .5% argon "Penning mixture".

Oddly enough, the argon makes the electrode glow a more yellowish shade of orange. The argon apparently detracts from red neon wavelengths more than the strongest yellow wavelength of neon, and produces essentially only infrared wavelengths of argon. In lamps with a main discharge column on the other hand, this mixture glows purplish to hot-pinkish in comparison to pure neon.

To get good life expectancy, any neon glow lamp should be supplied with only a little more current than it takes to get the electrodes completely covered with glow. A mere .5 milliamp peak tends to do that with A1A and A1B lamps. (If the current falls short of getting the glow fully covering the electrodes, then the glow may jump around, causing a distracting flickering effect.)

"High intensity" neon lamps appear to me to be the ones that are problematic with not reliably starting in complete darkness, especially after having been used for several thousand hours. Those appear to me to contain close to pure neon, and glow more brightly with a more reddish shade of orange than "standard intensity" ones do. They are also favorable to higher current of ~3 mA peak.

=============================

Should your application be an indicator lamp one rather than needing the electrical, finer spectral or optical characteristics of neon lamps, I can suggest some LEDs instead. I know of ones that produce more light than neon lamps do at same current, with ~~1/20 of the voltage drop.

For example, Cree C535A-WJN-CU0V0231 is a Digi-Key-available white LED that costs 58 cents apiece in quantities of 1. Its "rated viewing angle" is 110 degrees. (Brightness at 55 degrees off-axis is supposedly half that on-axis.) At .5 mA, this LED appears to me slightly brighter than an A1C neon lamp is at 1.3 mA - actual personal experience. And I know of some green and blue LEDs that get this visible with even less current, along with some red ones that get decently bright at a milliamp or two.

They used to exploit this effect in candelabra-type bulbs with flame-shaped electrodes, to simulate candles.

Cheers! Rich

Are first rate NE2's still in production?

Yes. Thousands in stock at Mouser (search for NE2).

Cheers, John

Fascinating retro technology.

A thing of beauty but too much for me.

Greegor expounded in news: snipped-for-privacy@q2g2000pre.googlegro ups.com:

Even if that were to quit working in the night, it would still keep the bedroom warm!

Warren

Yup, over 90 vacuum tubes (not counting the nixies) and close to a KW power dissipation. Not really practical.

Jon

Even he mentions the electric bill! LOL

This one looks like more fun.

Greegor expounded in news: snipped-for-privacy@z27g2000prz.googlegr oups.com:

Looks like fun but I don't really like neon tubes too much. They change over time too much and fail all too often (notice above the need to bin and age them prior to use).

Almost every power bar I've ever owned has developed failed or failing neon bulbs in them. Anything else I've ever had (neon panel lamps) have suffered the same fate. Neon bulbs are probably less reliable than your garden variety receiving tubes. So I can only imagine the perpetual need to maintain these hobby master pieces.

Warren

It's a damn shame that tubes rarely last more than 70 years.

I'm told this is because they're willing to sacrifice life for the sake of brightness. I.e., if they hadn't driven the bulb so hard, it could have easily been made to last at least a decade or so.

Joel Koltner expounded in news:hBT9p.414998$ snipped-for-privacy@en-nntp-07.dc.easynews.com:

That's probably true.

But operated at "proper" levels (or less), how long do neon tubes behave?

For these counting circuits, the hysteresis needs to stay reasonably stable to function correctly. 10 years doesn't seem like a long time, given how fast my last ten years have swooped by!!

Warren

Most are rated 20,000 or 25,000 operating hours.

Standard intensity ones with 120 VAC tend to fade without other signs of going bad, and provide a couple or a few more 10,000's of hours. That is, if not overdriven.

High intensity types usually go flickery, and then a few 10,000's of operating hours later, refuse or largely refuse to even flicker at 120 VAC.

With much higher voltage such as 230-240 VAC, neon lamps (when not overdriven) tend to fade but otherwise refuse to die until way past 25,000 operating hours.

Sometimes you do actually show a glimmer of active brain tissue.

The key is the fact that they are no longer manufactured under tight process controls, which is why they have such wide operating parameters from one to another, and very poor characteristics compared to any of the early, generally mil based versions of old.

Archie, This will go on your newest ASSESSMENT.

Don Klipstein expounded in news: snipped-for-privacy@manx.misty.com:

Interesting. So if you built a hobby clock out of them (assuming continuous on), then you'd only get

If they were not continuous on, but operating as decade ring counters, then I suppose you might get up to 10 times that in longevity.

I only asked because it looked like a fun thing to experiment with, though I don't have time for it now.

I'm not generally fond of high maintenance projects. This kind of project appears to be best for those with time on their hands. So I may revisit this in retirement, which is still a long way off. By then, a 10 year life span might be just about right! :)

Thanks for the interesting NE lifetime info.

Warren