I used to hear about something called the halogen cycle when I
worked as a technician with audio visual equipment.  The idea was that
a halogen lamp filament gives off vapor when run at reduced brightness
and that the vapor redeposits back on to the filament when it was run
at full brightness.  I don't know if this is for real or one of those
bits of urban wisdom that turn out to be either just flat wrong or based on
out-dated information.

        The halogen bulbs used in projection equipment are usually quite
expensive for light bulbs so people try to baby them as much as possible
when the replacement bulbs come out of their pockets.

Martin McCormick 405 744-7572   Stillwater, OK
OSU Center for Computing and Information services Data Communications Group