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From: jeff@rtech.ARPA (Jeff Lichtman)
Newsgroups: net.consumers
Subject: Re: Lifetime Lightbulbs
Message-ID: <120@rtech.ARPA>
Date: Wed, 30-Jan-85 22:19:16 EST
Article-I.D.: rtech.120
Posted: Wed Jan 30 22:19:16 1985
Date-Received: Fri, 1-Feb-85 21:51:14 EST
References: <-28400@cadovax.UUCP> <6100001@hpfclv.UUCP> <1467@hplabs.UUCP> <647@aluxe.UUCP> <1516@hplabs.UUCP>
Organization: Relational Technology, Berkeley CA
Lines: 32

> > ****                                                                 ****
> > From the keys of Steve Henning, AT&T Bell Labs, Reading, PA aluxe!2141smh
> > I've also heard that light bulbs that last forever can be made
> >   you can insert a diode in the line to effectively  halve the power
> > You can also buy 130V bulbs to accomplish much the same thing.
> 
>     Here's one point that hasn't been made yet.
> The use of a diode changes the current going through
> the bulb from AC to pulsating DC.  If that current
> is smoothed out (e.g. a full wave rectifier and/or
> a capacitor) then one has direct current.  One of
> the causes of light bulbs burning out is the
> stress on the coils in the filament caused be
> electro-magnetic interaction (though startup shock
> is still a big killer).
> -- 
> ----------------------------------
> 	Jim Davis (James W Davis)
> Email:	{any_of_the_biggies} !hplabs!davis
> Arpa:	davis%hp-labs@csnet-relay
> ----------------------------------

The Lawrence Hall of Science in Berkeley has an exhibit on saving
electricity.  They claim that pulsing an incandescent light on and
off doesn't affect its life very much.  They have two lights running
next to each other, one pulsing about once a second with a 50% duty
cycle, and the other running normally.  They claim that empirical
evidence shows that the life of an incandescent lamp (measured in
hours of light produced) is not affected by pulsing.
-- 
Jeff Lichtman at rtech (Relational Technology, Inc.)
aka Swazoo Koolak