Re[3]: Zenon bulbs?

[Brian Gracek <bgracek@cloudnet.com>]

>wow brian...i dont wanna sound lame...but can you explain this again so i
>can understand it..8)
>i use to drive a honda...so i am a little slow with things..
>geo
>-----Original Message-----

Sure I'll try...

The halogen bulbs we all use are made with a tungsten filament (little coil
of wire inside the bulb), the bulb is the evacuated (all the air sucked
out), then a halogen gas is placed in the bulb.

The halogen gas glows when heated by the filament...while the bulb is what
we would call hot (it will burn you), in the world of lighting it isn't
very hot so the color we see is yellowish.

The HID (high intesity discharge) lamps we see in the expensive cars
described (Porsche etc) in a gap between two high voltage electrodes.  The
Xenon gas is different from a halogen gas (I won't go into quantum
mechanics and molecular orbnital theory here...just know that they work
differently) in it will emit a whiter light when heated to a higher temp
(the halogen gas would decompose and ionize at these temps and be useless).

The big lesson here is temperature is DIRECTLY related to color output.
Let me give an example that I used to use on audiences when I worked in a
planetarum.  Think of a blacksmith working on an iron bar...removing the
bar from the hot coals shows the bar glowing red, the bar is hot but is
relatively cool on a temperature scale that applies to a star, so red is a
"cool" color.  Now imagine we can make the fire hotter and heat the bar
some more...remove the bar and it glows yellow (like our sun) at this point
the bar is molten actually...if we heat the bar some more it glows white
(i.e. white hot)  at this point the bar is actually boiling!   If we could
heat the bar even more it would glow blue...and heating even more and only
UV is emitted...

so, the bluer, the hotter the gas is in the bulb...the redder, the cooler
the bulb.  Remember the rainbow?  ROY-G-BIV... IR then, Red, Orange Yellow,
Green, Blue, Indigo, Violet...then UV
so it goes on the energy spectrum...red light is a low energy photon violet
is a high energy one...and UV enven more, that is why people worry about UV
radiation (light)...it is higly energetic and can damage cells...

So the differences are in the gas and the temperature.

So, why add Xenon to a halogen lamp...well it MAY provide some help, even
though the temps are a bit cool, population probability tells us some (very
few) atoms will be in the ulrta excited state...if some xenon atoms are
excited then we may get a small bump in output...BUT

it is the same calculations that show nearly every xenon atom will be in
the excited state at a higher temp which is only available without a
filament and within an arc!  So they designed a HID.

***********************************************************
Brian "Jetta TREK" Gracek		    Saint Cloud, Minnesota, USA

"On the road of life"...There are 'windshields', and there are 'bugs'
		          (splat!)

		"Squeegees Wanted"