|Application:||General Lighting / Decorative / Special Effects
|Length:||300mm (including pins)
|Bulb/Tube material:||Glass, pale blue phosphor coating on inner wall
|Peak output wavelength:||Unknown|
|Total Light Output:||Unknown|
|Cap:||Bi-Pin fluorescent fitting
|Operating voltage:||56V AC
|Warmup/restrike time:||1 minutes/none|
|Value (now):||£5.00 approx.
|Place of manufacture:||England.
|Date of manufacture:||Unknown - Code 20E printed on lamp.
|Lamp Status:||Working, presumed new - no packaging provided.
|Notes:||Here we have a
garden variety (well...not quite, I imagine you'd be quite surprised if
you found one of these in your garden...you know what I mean though!)
F8T5 fluorescent tube. Who made it I have no idea, as there is no
makers name printed on it anywhere, nor was there any packaging
supplied with it.
One of my long standing interests in lighting terms has been fluorescent lamps in unusual colours. While blue isn't by any means unusual, it's different enough to your normal various shades of white that it interests me.
The phosphor on this one relative to your normal "white" tube seems to have a lot less in the way of red emission, with a nearly continuous output from mid green through to deep blue. This results in quite a pale blue colour to the light. Somewhat less green though than the lights you tend to see used to attract insects though, despite the similarity in the photos below. There is sufficient deep blue output from this light to cause considerable fluorescence from many typical fluorescent coloured objects.
This particular lamp attracted my attention initially as well due to the end caps seeming to be a couple of mm smaller than on most of the other F8 tubes I have - being quite a bit narrower than the tube itself. This and the fact that the phosphor doesn't actually go all the way to the cap means that you can see into the tube a little at each end, the closeup shown below lets you see the bright reflection from the phosphor internally.
The one downside of the particular phosphor mix is that it appears to have a far shorter persistance (time taken to stop glowing) than the normal triphosphor mix. This means that when operated on a conventional magnetic ballast, it flickers quite a lot more visibly than normal white lamps.
If anyone can suggest which company may have produced this lamp and put a date on it I'd be really grateful to hear from you.
|Click thumbnails for full size images|
added to the Virtual Display Shelf on the 26th August at 22:56.
Exhibit number: 79.
References: F8T5 Datasheet on SLI Lighting's website (to obtain current/voltage specs).
Acknowledgements: Many thanks to the website visitor who donated this (and many other!) lamps for display.