71   General / General Discussion / Re: Gas filling in T5 fluorescent tubes (classic, HE, HO, energy saving versions)  on: March 21, 2026, 03:15:00 PM 
Started by PlasmaAddict - Last post by RRK
And finally, some interesting offtopic on spectral investigations ;) A crime case of some circa 2023 recent shitty Russian 36W T8 tube from my home, probably originated from Smolensk, but not branded Russian Osram. It got mercury starved and was replaced, but I kept the tube out of curiosity. It burns dim whitish with pronounced stirations. As you can see the spectrum shows near - 100% krypton fill, and no trace of any foreign molecular gas like oxygen or nitrogen. So it got really mercury starved, not leaked! You see only very weak  mercury lines and very weak phosphor excitation, as krypton has just a weak UV and at very short wavelengths, halo phosphor is insensitive to these. I do not have a starved argon tube yet to investigate, though.

 
 72   General / General Discussion / Re: Gas filling in T5 fluorescent tubes (classic, HE, HO, energy saving versions)  on: March 21, 2026, 02:27:16 PM 
Started by PlasmaAddict - Last post by RRK
Now! Gotcha! Rather old original Italian Osram FH 21W/840 *HE*! Here I 100% agree with @James listing. Dominant krypton lines with some weak argon lines. Krypton having lower ionization potential will dominate even at low percentage.

Also, my own handmade cold cathode tube with pure krypton as a spectral reference!

 73   General / General Discussion / Re: Gas filling in T5 fluorescent tubes (classic, HE, HO, energy saving versions)  on: March 21, 2026, 02:18:24 PM 
Started by PlasmaAddict - Last post by RRK
Rather recent Chinese Osram 24W/HO 840. Still no trace of Ne, some signs of alcali earths sputtering with glow discharge at 20mA.
 74   General / Off-Topic / Re: Severe weather never sleeps!  on: March 21, 2026, 08:08:45 AM 
Started by lightinglover8902 - Last post by suzukir122
Looks like we'll be hitting the 80's here tomorrow, close to the mid 80's... with the threat of storms tomorrow as well. Severe weather threat possible.
Then Monday it'll only be 48 degrees, probably cold night Monday night as well but I forget.
Sheesh man, the temperature swings...
 75   General / General Discussion / Found a new cool site with atomic spectra visializations. Enjoy!  on: March 21, 2026, 07:26:54 AM 
Started by RRK - Last post by RRK
Look here:  https://www.atomtrace.com/elements-database/

Click the element of interest.

 76   General / General Discussion / Re: Gas filling in T5 fluorescent tubes (classic, HE, HO, energy saving versions)  on: March 21, 2026, 07:03:08 AM 
Started by PlasmaAddict - Last post by RRK
Red T5HO 24W Osram tube tortured in the name of Science! ;) Gods of fluorescents, forgive me...

Run freezed at 20mA, shot near the electrode, then at the middle of the tube, run-up full current. I believe in the blue-green area I see barium and strontium lines from atoms sputtered off the cathodes of this poor little tube. I feel the pain you suffered, won't do it any more, trust me :)

I can not see any sign of neon present. 

Also you see red phosphor YOX, Y2O3:Eu bearded red line spectrum in a full glory, here not polluted by yellow and orange bands of terbium phosphor.

Spectrum from the green tube also contains a strange peak at ~589nm, it *may be* a line from neon, but usually cathode glow of neon is dominated by slightly shorter 585nm line.
 77   General / General Discussion / Re: Gas filling in T5 fluorescent tubes (classic, HE, HO, energy saving versions)  on: March 21, 2026, 05:13:51 AM 
Started by PlasmaAddict - Last post by RRK
@James

Well okay ;)

So you convinced me to torture this little rare tube by freezing it at -18C for some time and then running briefly from 20mA neon transformer. Here you can see the spectrum I captured in the area near the electrode. A bit noisy as the light is weak at small current. For comparison, also the spectrum from the middle of discharge column with a cold tube (typical Ar infrared signature) and from a hot run-up tube (Ar lines suppressed, only green Tb phosphor + some mercury now).

The only suspicious spectral line which may belong to Ne I see with cold tube near the cold cathode is a small peak at ~649nm. Does not look to be typical Ne wavelength too, but who knows.

 
 78   General / Off-Topic / Re: Severe weather never sleeps!  on: March 21, 2026, 02:40:18 AM 
Started by lightinglover8902 - Last post by Cole D.
It’s mostly been back to the 70s and 80s for highs here. I was wondering if we’d have any further cold fronts this spring, and I was doubting we would. But we did get another this week. Tuesday evening it started to thunder and blow really hard with a very dark sky and then started raining all evening, which we really needed. That was one of the more chaotic cold fronts we’ve had in a while. The temp did drop down again to lows in the 40s and highs in the 70s again the rest of tgis week.
 79   Lamps / Modern / GE light bulb updates  on: March 21, 2026, 02:33:15 AM 
Started by Cole D. - Last post by Cole D.
I noticed Dollar General and Family Dollar were still selling the 15 watt and 25 watt incandescent GE bulbs in twin packs. Just recently though, they’ve been replaced by LED snow cone equivalents in a single pack. The higher wattage incandescents are still available.

Also, Dollar Tree has started stocking some GE incandescent bulbs, including the 250 watt 3 way bulbs.

Last weekend I went to Tractor Supply and most of the GE bulbs were on clearance, including 3 way LEDs and 70 W Lucalox, among others. I wonder if they will stock a different brand soon.
 80   General / Off-Topic / Re: Severe weather never sleeps!  on: March 21, 2026, 12:22:07 AM 
Started by lightinglover8902 - Last post by xmaslightguy
Lines are underground where I'm at, but I can say this:
If a line comes down (lets just say in a storm as an example), the flash is *bright*, you can easily see it from a mile away at night! - I've witnessed it in person.
If its not the line supplying your area, obviously you won't be affected by an outage.

Where I'm at a transformer powers 8 to 10 individual houses, if one of those transformers goes out(they have protection to shut down rather than explode(something not all tranformers have)), just that small group of houses will be affected with an outage, not the whole neighborhood. (and same type of thing for apartments, depending on how big the building is, each building might have its own transformer).
And something like that could send an inductive kick down the lines (or simply a burst of 'noise' on the line). That could be enough to RCD/GFCI if its a bit sensitive.
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