Return to the thumbnail page Display/hide file information See next file

Sylvania LU70/D Electrostatic Excitation

Sylvania LU70/D Electrostatic Excitation


Today I took an old 1990s Sylvania LU70/D lamp out of its packaging in a relatively dark room, and was astonished to see a bright red flash. At first I was not sure whether to believe what I had seen, but then it happened a second time during normal handling, and I found that the effect could be repeated by moving the lamp rapidly against the hands so as to generate a static electric charge - see video above. I have never observed such an effect before so easily with any lamps, although the principle is of course familiar from the experiments of Francis Hauksbee in 1705 who produced light by rubbing an evacuated glass globe containing a small amount of mercury.

In this case the outer envelope of the lamp is of course under very high vacuum. No visible discharge is apparent inside the bulb, the light is produced by fluorescence of the diffuse coating.

Sylvania was unusual in that many of its high pressure sodium lamps produced years ago in fact used phosphor coatings as the diffuse material of the outer jacket - even though the HPS lamp has no UV radiation and a phosphor has no purpose. Perhaps this was for reasons of standardisation to use the same coatings as mercury lamps. In a mercury lamp the outer jacket is of course generally filled with nitrogen, which presumably prevents such easy build-up of surface charges from frictional effects. However HPS lamps usually have evacuated outer bulbs, and when combined with a phosphor coating would appear to allow surface charges to be generated wit sufficient magnitude to excite the phosphor.

youtube_BAg7J4dzEnc.jpg D SHP Philips SDWR50.jpg D SHP Philips SDWAR22.jpg D SHP Philips SDWAR22 powercurves.jpg

Light Information

Light Information

Manufacturer:Sylvania
Model Reference:LU70/D
Lamp
Lamp Type:High Pressure Sodium
Base:E39
Shape/Finish:BT-23.5
Electrical
Wattage:70W
Physical/Production
Fabrication Date:1992

File information

File information

Download: Download this File
Filename:youtube_BAg7J4dzEnc.jpg
Album name:James / Sodium High Pressure
Keywords:Lamps
File Size:7266 Bytes
Date added:Apr 09, 2019
Dimensions:480 x 360 pixels
Displayed:99 times
URL:https://www.lighting-gallery.net/gallery/displayimage.php?pos=-158386
Favorites:Add to Favorites
Comments
fluorescent lover 40
Full Member
***
Offline

Gender: Male
Posts: 221
View Gallery

Lights are awesome! :)


View Profile Personal Message (Offline)
Apr 09, 2019 at 04:10 PM Author: fluorescent lover 40
Very interesting phenomenon James!

Power provider: Southern California Edison (SCE)

-Date decoder of some US lamps 1960-present.
-Switch and receptacle collector.
-I'll save what I can! Smiley

Bulb Freak
Newbie
*
Offline

Gender: Male
Posts: 41
View Gallery


View Profile WWW Personal Message (Offline)
Apr 09, 2019 at 04:37 PM Author: Bulb Freak
very cool to see

IIRC user FrontSideBus, has a modern cheap Crompton SON-E/I 70W HPS lamp that also has a phosphor coating despite being a Sodium lamp

I wonder if his lamp exhibits the same phenomena

My other hobby is buses, especially the Routemaster

don93s
Sr. Member
****
Offline

Gender: Male
Posts: 425
View Gallery


View Profile Personal Message (Offline)
Apr 09, 2019 at 06:05 PM Author: don93s
Very cool James! Perhaps you merely have hidden superpowers we don't know about, lol.
ace100w120v
Hero Member
*****
Offline

Gender: Male
Posts: 681
View Gallery


View Profile Personal Message (Offline)
Apr 09, 2019 at 07:11 PM Author: ace100w120v
That's beautiful! Around here in the winter it gets quite dry and it's quite fun to play with a fluorescent tube or CFL in the dark with a piece of charged clothing such as a sock fresh from the dryer.
dor123
Hero Member
*****
Offline

Gender: Male
Posts: 2588
View Gallery
Other loves are computers, office equipment, A/Cs


View Profile WWW Personal Message (Offline)
Apr 09, 2019 at 07:38 PM Author: dor123
I've managed to see this once with CFLs, when the tube would glow dimly when I hold it in a dark room. I've managed to do this with hot CFL only.

I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the European date format (dd.mm.yyyy).

I lives in Israel, which is a 230-240V, 50hz country.

Silverliner
Administrator
Hero Member
*****
Offline

Gender: Male
Posts: 705
View Gallery

Verd a ray classic.


GoL
View Profile Personal Message (Offline)
Apr 09, 2019 at 11:31 PM Author: Silverliner
Very cool! You made a plasma ball out of your own power! I shall try this someday. I have a few Sylvania HPS diffuse lamps.

May all the great lighting technologies have their place in history.

Administrator of Lighting-Gallery.net. Need help? PM me.

dor123
Hero Member
*****
Offline

Gender: Male
Posts: 2588
View Gallery
Other loves are computers, office equipment, A/Cs


View Profile WWW Personal Message (Offline)
Apr 12, 2019 at 09:52 PM Author: dor123
Here is my experience with CFL .

I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the European date format (dd.mm.yyyy).

I lives in Israel, which is a 230-240V, 50hz country.

Ash
Hero Member
*****
Offline

Posts: 3738
View Gallery


View Profile Personal Message (Offline)
Apr 13, 2019 at 01:27 AM Author: Ash
I have seen similarly-looking discharges with a Mercury lamp, holding the envelope in hand and giving an impulse from a small piezo ignitor to the cap. The discharges seem to take the form of thin paths in the phosphor

(To anyone trying it : I recommend holding the lamp on top of a bed sheet or the like, so you don't drop it or smash it if you get a Pikachu from the ignitor)



In my attic are several cardboard boxes in which i store tubes. The boxes are not tall so most of the tube length stands out vertically. I tied a wire around the upper end of the mass of tubes and a beam supporting the roof, to prevent a box with tubes from falling sideways. Most (95%) of the tubes are 36/40W, also there are few 110W F96T12s, and a 8ft Neon tube from a Neon sign (transparent T5-ish straight tube filled with Neon, glows Red)

On a dry night, if i just move near the tubes with a block of styrofoam (without rubbing it first on anything, just the presence of it), makes some tubes flicker. The Neon seems particularly happy to flicker to the static as well
monkeyface
Full Member
***
Offline

Gender: Male
Posts: 149
View Gallery


View Profile Personal Message (Offline)
Apr 13, 2019 at 01:51 AM Author: monkeyface
Very nice phenomena! It brings me back memories about my fluorescent lamp collection in my childhood. In wintertime when I put a fluorescent tube on the carpet the tube startet to flash very dimly when I touched it and when I moved it along the carpet.
rigo
Newbie
*
Offline

Gender: Male
Posts: 17
View Gallery

View Profile WWW Personal Message (Offline)
Apr 13, 2019 at 06:42 AM Author: rigo
Hello James, I know the effect of NARVA HQL lamps. Whenever I break down the light trap at night and pack the lamp, this effect can be seen. Often quite bright.
Max
Jr. Member
**
Offline

Posts: 71
View Gallery


View Profile Personal Message (Offline)
Apr 14, 2019 at 02:23 AM Author: Max
Nice experiment James! I also remember seeing this phenomenon in other HPS lamps which were definitely not coated with a phosphor (no visible fluorescence from trivalent Eu at startup). Calcium pyrophosphate can have electro/cathodoluminescent properties in the presence of some impurities.
© 2005-2019 Lighting-Gallery.net | Powered by: Coppermine Photo Gallery