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)

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.


 

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?

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.

 

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)

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!

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

Neon shop has tube blanks in 8-18mm outside diameter usually, rarely up to 25.

They generally can not make hot cathodes, the best you can hope is 18mm cold cathodes that can run up to 100-120mA usually.

Pretty much no one coats its own glass today except some Germans.

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

Cathode voltage drop is the answer. To make tubes efficient, they need to be long and thin and high voltage, which is all not home friendly )
Though, in the era before led strips, neon (cold cathode lighting) was used at home sometimes.

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)

Well, like I said before, switching neon supplies are relatively benign interference-wise. They run on sinewave and typically have an inverter tuned to be close to zero-voltage switching mode. It is a PFC circuit mandatory for most electronic fluorescent ballasts which appears to be typically a major interference offender. PFC runs a MOSFET at hard switching having nanosecond edges at rather high voltage and current and easily pollutes the bands up to about 2m VHF radio despite some filtering coils applied.

Also, if you are under impression that discharge lamps are interference free on magnetic gear, well this is not true and the problem is known for decades, especially in the old times when AM radio use was significant. A combination of negative resistance nature of a discharge lamp with LC of a ballast circuit gives some sawtooth oscillations, large or small depending on circumstances.

Here is a waveform I captured from a neon tube running on a 3kV magnetic leak transformer. Just a bit exaggerated, because it is 8mm red neon tube and runs the transformer a bit overloaded by voltage, but yours does some oscillations too!

https://www.lighting-gallery.net/gallery/displayimage.php?pos=-225979

Here is a waveform captured from T8 fluorescent tube running on a magnetic choke @50Hz. You sure see some HF hash too.

https://www.lighting-gallery.net/gallery/displayimage.php?pos=-225951

HPM lamps sometimes do even sharper transients on the electrodes, even resistively ballasted mixed light ones, going into VHF range!

 

Nice captures, thnx

I know they are not, I even read an article once where they talked about supression of interference from magnetic neon sign transformers (would love to try that in person once (comparing electronic neon transformer to magnetic one), to see how much RF interference did they make, but don't want to get a neon sign and then once I find out it produces to much RF interference for my needs throw it away)

but my experiments (not many) that I did with flurescent tubes and HPS bulbs, showed that magnetic gear, even if it produces some RF interference its not much, and if I use magnetic gear I will usualy be fine

here is souch an example where I actualy do hear a magnetic ballasted flurescent tube: https://www.youtube.com/watch?v=5YFqrgB-CPY (although it could also be a noisy outlet I was on)

Here is one souch a test, you can see I can hear the igniter: https://www.youtube.com/watch?v=940m6wxZjaQ
but once the igniter does its job its quiet (for my needs)

So then I learned that magnetic gear is better (way easier to find something that will be quiet), so I always try to find and use it
I am sure that good quiet electronic transformer for flurescent tubes and HID lamps and neon exist, I just haven't be able to find it yet, same with switch mode power supply, people don't advertise this things, so its eather, try and throw away, or get lucky (I do have an extremly quiet swichmode power brick for my Sangean ATS909X, I just wish I could buy a similar one )in different voltages and current)