Author Topic: What light is this?  (Read 1012 times)
veso266
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What light is this? « on: April 02, 2025, 06:36:09 AM » Author: veso266
I have this bathroom fixture
https://imgbox.com/iAfZpLFH
https://imgbox.com/XbRoYa9h
https://imgbox.com/nq94qM2b


It (the bathroom cabinet) was custom made in the 70s

the lamp was never replaced, and I hope it will never need to be

At first I thought this was a magnetic rapid start flurescent light, but when I had to put the fixture down for cleaning and saw a transformer, I am suspecting it might be a neon light inside

Did they ever make square flurescent tubes? I know they made circular flurescent tubes, but not sure about square ones

I am wondering this so I can find a replacment incase the light breaks on me (the transformer hums as long as I can remember, but everything still works)

Its also interesting that this light did not change color (usualy flurescent lights as they age, change color from white to yellow as something happens to the fosfor coting)
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LightsAreBright27
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Re: What light is this? « Reply #1 on: April 02, 2025, 09:42:01 AM » Author: LightsAreBright27
The links aren't working. Is the tube a complete square, or is it like a 2D fluorescent lamp?
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RRK
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Re: What light is this? « Reply #2 on: April 03, 2025, 01:21:15 AM » Author: RRK
Tube image is blurry, but it looks like custom made neon tube.

In fact, aging fluorescents do not change color that much (though especially halophosphate phosphors DO lose some light and drop CRI). It is more plastic parts of a luminaire yellow over time.
Neon (cold cathode) do age and dim too, but may be do this slower because of lower power loading.
You can get a replacement modern electronic neon power supply easily, as a bonus, these do not hum any more, on even conventional magnetic transformer.
Neon tube most likely runs at usual 30 milliamps, but units made for lighting specially may be rated for higher current, say, 60mA. You have to guess some way or look at transformer nameplate (if any) or measure *carefully, high voltage*.

If needed, a custom neon tube of any shape desired can be ordered from a neon maker nearby, not extremely expensive.


 
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veso266
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Re: What light is this? « Reply #3 on: April 03, 2025, 05:39:10 AM » Author: veso266
Wow, nice, I always wanted to have a neon+argon (like blue color) sign (but not sure if anyone makes theese in Slovenia and also if I could find old magnetic transformer for it (since I hate modern swich mode power supplies, cuz they produce RF interference)), never knew I already have a neon light :)

Here is a video of it running: https://www.youtube.com/watch?v=M63_021NPtU
not sure how to make better picture since I am not sure if this tube even comes out of there

How did you know its a neon tube and not flurescent one?
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RRK
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Re: What light is this? « Reply #4 on: April 03, 2025, 07:59:11 PM » Author: RRK
Well I think it is neon because there is no known fluorescent tube of that shape and blue streaks on the picture look similar to what you expect to see in uncoated neon tube electrode ends typically attached at 90 degrees.

Okay. Proper terminology is hot cathode and cold cathode, related to the mode of injection of electrons from power supply into the discharge. Otherwise, discharge column physics in fluorescent and mercury filled 'neon' tubes is exactly the same and you can just not tell them by the look! So I have just a guess! There was also custom shape sign tubes but with hot cathodes.

Good to know electronic neon supplies run with close to the sinewave voltage and current, so radiate a little interference beyond main frequency of 20-50kHz and some lower harmonics, so not to worry much.

 
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veso266
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Re: What light is this? « Reply #5 on: Today at 03:20:34 AM » Author: veso266
I do wonder, why we used Flurescent lamps instead of neon at home

It seams neon is better cuz it starts imidiatly and doesnt die, and best of all, its not banned (at least I think it is not) and can still be made in a neon shop

PS: u think u could show me how much interference electronic neon transformer make? (I dont have any and dont want to buy one just so I can throw it away later)

Just get AM radio close to transformer

I do have bad expirience with electronic flurescent ballasts, look here: https://youtu.be/RLq8vfancbg

Thos one is instant start and is supposed to be certified (in the manual they even claim how little interference it makes), but u can still hear it on ur radio

Its not as bad as this one powering my grow lights: https://youtu.be/GA7rscFNpB8
Fortionatly it died, so I replaced it with a quiter one, but still not completly quiet, cuz I was not able to find magnetic rapid start ballast (and fixture didnt have space for preheat one + starter)
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Laurens
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Re: What light is this? « Reply #6 on: Today at 05:02:26 AM » Author: Laurens
Cold cathode fluorescent lamps (which is what "neon" tubes are that have mercury or argon filling but a white or colored fluorescent coating on the inside) have been attempted in the 60s, but the major downside is that you need many kilovolts and that means very thick isolation, making it a hassle to use it for general lighting.
Instant start hot cathode fluorescent tubes with only 1 pin per side also exist. They are called TL-S and don't need a starter - only a ballast of some sort. Once those were in production, the big benefit of CCFL (instant start, no flickering, only 1 wires per tube) were matched by the TL-S.
But even the TL-S never became very succesful outside of street lighting. They are marginally less efficient, i have no idea yet about how expensive those were compared to the standard fluorescents.

Your bathroom cabinet/mirror is pretty special. Take good care of it. At first i thought it was just a modern LED mirror because i sold some very similar ones in the 2010s, but then i saw the rear of it. It's very futuristic!
I think the only reason why it uses a "neon" lamp is because it was made in the eastern bloc, and that economy allowed things to be produced that make no sense at all from a modern and/or capitalist point of view. Custom size CCFLs are very expensive to produce here, but if the local neon tube factory over there got the order to produce 1000 of these things, it would just happen. There's also a story about the most popular little washing machine from the Soviet Union, that had production costs of triple the sales price. Despite that it was in production for years, simply because people needed washing machines and the factory just produces what the Central Planning Office tells them to produce, as long as said office makes sure they get the raw materials they need.

In the west, these things would just be made with 4 13w thin fluorescent tubes with light spreaders for the corners or something. Unless demand is so large that it starts to make sense to let Philips/Osram/whatever whip up a batch of 100.000 of those lamps, and it becomes economical to fire up a dedicated production line.

Very thin CCFLs eventually found use as backlight, and in very small numbers in CCFL-style lamps (you can find one example in my gallery). This was possible because of advances in solid state inverter technology.

Bans in the EU are done based on 2 factors: efficiency and mercury content. These are thus far only valid for general purpose lighting and street lighting. All mercury containing products have been banned from being imported or produced or will be in the next 1 or 2 years. Efficiency you'll have to look up, there's a list with usage and lm/w it needs to reach. For example, the very first LED lighting is technically also already banned, you wouldn't be able to produce a lamp that contains old stock LEDs from 2008

But because neon signs are not general purpose lighting, they're outside the scope of these regulations. Technically you could ask a neon tube maker to make whatever size neon tube you want with whatever phosphors you want, with a mercury filling, and install them as lighting in your home. It would just cost you hundreds of euro lol

One word of advice: figure out what voltage your transformer puts out, by connecting it to a low voltage AC power source (like a doorbell transformer) and measuring the voltage that appears on the tube, and calculate the transformation ratio. That way you know what to buy voltage wise, if the tube ever breaks.
Do not measure the high voltage on mains! It can be many kilovolts and will destroy your meter, or worse arc through your measurement leads and destroy you!
« Last Edit: Today at 05:14:41 AM by Laurens » Logged
veso266
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Re: What light is this? « Reply #7 on: Today at 05:58:13 AM » Author: veso266
Well, I already paid 100€ for 6leds (canopy, they go in the hole in the wall)+drivers (I wanted somewhat RF quiet ones), so, yea, lights can be expensive 😀

I wonder if neon sign maker could make me a new T8 or T12 or T18 flurescent tube

Since its just a tube filled with gass, sealed and phospor coated, and u dont even need to twist it or something

And nepn shops already have equipment to fill, seal and coat glass

The onlything I am not sure is where to get electrodes compatible with preheat ballast
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