<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by pez:
<strong>Although the acronym might be meaningless, don't DE lamps generally need a special ballast (usually designated with HQI somewhere)?</strong><hr></blockquote>
Tom -
You are correct.
FWIW, HQI stands for "Halogen Quartz Iodide". Which was a lighting technology once used in these lamps. They have evolved over the years and today double-ended lamps are really just Metal Halide, even though people still call them HQI.
I believe that the HQI ballast requirement is partially due to some of the other "things" you see inside a single-ended mogul metal halide lamp. There are resistors & thermistors and other stuff that helps to fire them, but all this is lacking in the double-ended lamp - the ballast has to do all the work.
[ March 22, 2002: Message edited by: MattM ]</p>