In article , clare @
snyder.on .ca mentioned...
On Wed, 03 Sep 2003 10:15:14 -0700, Lizard Blizzard
wrote:

Ban wrote:

Watson A.Name - Watt Sun wrote:

Hey, I agree with you. But instead, I would have used higher voltage

lamps, two in parallel. Decent LEDs were hard to get back in the
'70s. Another solution might be to use neon lamps.


You mean flourescent lights. neon lamps need a high voltage
transformer. :-(

Neon lamps need a current limiting resistor, something like 47k or so,
but not a transformer. Some of the screw base neons have the resistor
built into the base. Some of the ones I've seen have a standard sized
'edison' lamp base with a glass envelope that's about twice the size of
the base. They last something like tens of thousands of hours. They
would solve the problem of burned out filaments.


The only problem is the (described) Neon lamp does not provide a high
enough light output for emergency egress signs. They tend to be a very
weak, flickering orange. Make a good pilot light, but not much more.

No, these are much brighter than a pilot light. Much bigger, too,
Since they're red, they put out the proper color light without
filtering.

But this whole neon lamp for exit sign thread is moot. The new ones
I've seen use LEDs and run off a SLA gel cell battery. Today I was
working in a hallway with an exit sign that was about a foot (.3 m)
off the floor. During the recent remodeling someone had knocked the
cover loose so I took the cover off. I found that the sandwich behind
the cover was unusual. The front layer was a clear diffuser made of
plastic, sort of like the glass they use in bathroom windows, with
bumps on one side. Underneath the glass was a thick tray with grooves
cut (or cast) into it in the shape of the letters EXIT. Each groove
had a pale yellowish rod laying in it, a bit thicker than a pencil
lead. My guess is that this is some kind of phosphorescent material
that glows when light from flames from a fire are hitting it. There
is _no_ power to the sign.

This kind of exit sign seems to be standard on all newer built
buildings. And positioning them close to the floor is standard
procedure, because exit signs above the doors become useless as the
smoke rises and fills the room.

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