|Application:||Stroboscopic Ignition Timing Setup|
|Length:||80mm (including wire ended connections)|
|Tube Length:||140mm approx|
|Peak output wavelength:||Unknown|
|Total light output:||Unknown|
|Cap:||Wire terminals, no cap|
|Operating voltage:||Approx 150V running voltage.|
|Operating current:||140mA approx|
|Place of manufacture:||Unknown|
|Date of manufacture:||Unknown - estimated late 1960s - mid 1970s.|
I don't have much information on this lamp (as if the sea of "unknowns" above didn't already tell you that!). As for its maker and its age, I'll probably never know, not least as there are no markings whatsoever on it.
For such a small lamp, it gives out a really surprising amount of light, enough to walk around a room in the dark by, and to show up on my spectroscope. The photos make the colour appear a good deal more "washed out" than it actually is in person. In reality, the discharge is your typical saturated red-orange neon. There's also a typical deep orange negative glow seen at both of the solid electrodes. The gas filling in this lamp I believe to be a typical neon/argon mix, probably approx 99% neon, 1% argon though without someone more knowledgeable to look at it, I can't say for certain precisely what mixture ratios are used, can't be far from that shown above though.
The images here were captured by operating the lamp on a high frequency AC ballast, this has the interesting effect of setting up some visible "standing waves" in the discharge, which can be seen as light and dark areas in the discharge. The effect can be seen in all images where the lamp is in operation, though I also took a short video clip (963K) which better shows it. This is an effect which if you're in London you can quite often see in the fluorescent lamps used to light older trains on the District Line due to the type of ballast they use. That's totally unrelated I know...but I thought it might be of interest to the types of people likely to be reading this page!
A couple of people have been in touch, at least letting me know what the original purpose of this lamp was likely to be. Prior to xenon (and more recently LED) strobe lights becoming commonplace, neon lamps like this were used for setting up the ignition timing of petrol car engines. The lamp would probably have been fitted in a reflector originally, and would have been connected directly to one of the HT leads of the engine. This would result in the lamp firing once with each revolution of the engine, allowing the timing marks (usually on the crankshaft pulley) to be observed and adjustments being made as appropriate. Xenon and LED strobes have replaced these lamps now due to the fact that they are able to give out far, far brighter light.
If anyone's got any further information on this little lamp particularly with reference to its maker and age, I'd be most grateful to hear from you.
Miniature Wire-Ended Neon Spiral Lamp - General overview
Miniature Wire-Ended Neon Spiral Lamp - Showing negative glow at lamp cathodes while lamp is lit
Miniature Wire-Ended Neon Spiral Lamp - Shown while alight
Miniature Wire-Ended Neon Spiral Lamp Illuminating a wall in my room from a distance of approximately two metres
Miniature Wire-Ended Neon Spiral Lamp - Shown held in hand to give sense of scale
Miniature Wire-Ended Neon Spiral Lamp - Showing size of lamp
Miniature Wire-Ended Neon Spiral Lamp Output Spectra
Miniature Wire-Ended Neon Spiral Lamp - Detail of lamp connections
This lamp added to the Virtual Display Shelf on the 22nd March 2007 at 21:47.
Acknowledgements: Lamp purchased from LED Sales.
This page last updated:
19th June 2023: Changes to page formatting to improve readability on mobile devices, also made some background changes to improve search engine behaviour.