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From: frankb@hpsad.HP.COM (Frank Ball)
Newsgroups: sci.electronics
Subject: Re: Need quartz-halogen lamp info
Message-ID: <1840023@hpsad.HP.COM>
Date: 3 Jan 90 17:04:36 GMT
References: <7200047@silver>
Organization: HP Signal Analysis Division - Rohnert Park, CA
Lines: 24

*From: commgrp@silver.bacs.indiana.edu
*Subject: Need quartz-halogen lamp info
*
*I want to use (relatively inexpensive) 12-volt automotive quartz-
*halogen bulbs in portable (dc) configuration where I need maximum 
*illumination.  Automotive bulbs are designed for long life in a high-
*vibration environment, leading me to believe that I can increase the 
*voltage substantially and trade-off bulb life for extra light. (I can 
*minimize thermal shock by increasing the voltage above rated value 
*after the filaments are already hot.)  

GE and Sylvania publish info on their halogen lights.  I have some
very old copies.  They don't have all the info you want, but some.
I saw a graph that showed bulb life cut in half for a 10% voltage 
increase.  Even halogen lights have most of their output (about 90%) 
in the infared range, so more voltage would help the light output by 
shifting some of this into the visable region, as well as increasing 
the total output.

Automotive bulbs are not rated at 12 volts.  Cars can run up around
14 - 14.5 volts when running.  The GE headlamps are rated to last
200 hours at 14 volts.

Frank Ball          frankb@hpsad.HP.COM