Halogen lamps

[P3D Bob Wier <wier@xxxxxxxxxxxxxxx>]

In looking around the net (trying to find info on how to fix those
#*(Y(!Y(&Y Lights of America under kitchen cabinet lights that only last
6 months) I ran across a site with a LOT of information on various
lamp types (which is readable in large part without getting into
too much detail). It can be found at..

http://WWW.InterMarket.net:81/~don/light.html

Here's part of what is said on halogens - please forgive the lousy
formatting - it's a cut and paste from netscape to Eudora.
====
This process, known as the halogen cycle, extends the life of the
filament somewhat. Problems with uneven filament evaporation and
uneven deposition of tungsten onto the filament by the halogen
cycle do occur, which limits the ability of the halogen cycle to
prolong the life of the bulb. However, the halogen cycle keeps
the inner surface of the bulb clean. This lets halogen bulbs stay
close to full brightness as they age. In order for the halogen
cycle to work, the bulb surface must be very hot, generally over
250 degrees Celsius (482 degrees Fahrenheit). The halogen may not
adequately vaporize or fail to adequately react with condensed
tungsten if the bulb is too cool. This means that the bulb must
be small and made of either quartz or a high-strength,
heat-resistant grade of glass known as "hard glass". Since the
bulb is small and usually fairly strong, the bulb can be filled
with gas to a higher pressure than usual. This slows down the
evaporation of the filament. In addition, the small size of the
bulb sometimes makes it economical to use premium fill gases such
as krypton or xenon instead of the cheaper argon. The higher
pressure and better fill gases can extend the life of the bulb
and/or permit a higher filament temperature that results in
higher efficiency. Any use of premium fill gases also results in
less heat being conducted from the filament by the fill gas,
meaning more energy leaves the filament by radiation, meaning a
slight improvement in efficiency.

====
--BW

    ====== wier@xxxxxxxxxxxxxxx ======
  12:05 AM Thursday, January 2, 1997
   keeper of the Photo-3d, Motorola
 MC68HC11, Overland-Trails, LDS State
Research Outline Guides and other stuff
     (currently in Ouray, Colorado)



------------------------------

End of PHOTO-3D Digest 1783
***************************
***************************
 Trouble? Send e-mail to 
 wier@xxxxxxxxxxxxxxx 
 To unsubscribe select one of the following,
 place it in the BODY of a message and send it to:
 listserv@xxxxxxxxxxxxxxx 
   unsubscribe photo-3d
   unsubscribe mc68hc11
   unsubscribe overland-trails
   unsubscribe icom
 ***************************