AC vs DC lamps

[KSMITH1@mailgw.sanders.lockheed.com]

Hello lighting mavens:
     On the subject of lamp life versus ac ripple, it is my 
understanding that tungsten lamps last longer with ac than dc.  
Perhaps the positive end of a dc fed lamp emits tungsten ions easier, 
thereby preferentially weakening the filiment at that point.  Whether 
this materially matters to a tungsten-halogen lamp with its tungsten 
replacement cycle, I cannot say.  In any case, the level of ac ripple 
at the alternator, given reasonable wiring and battery health, is 
unlikely to have any effect at all.

***          ...Kirby    (Kirby A. Smith)  1988 90Q              ***
***              ksmith1@mailgw.sanders.lockheed.com             ***
***              [=]   kirby.a.smith@lmco.com                    ***
***  Opinions expressed herein are entirely those of the author. ***