At 08:29 AM 6/28/2006 -0700, you wrote:
> > I replaced one of of the (series string) bulbs with a (carefully
> > insulated) 1N4007 to knock the voltage down to 70% of line and get several
> > years lifetime 24/7.
> >
>
>
>Which reminds me... Some projectors use 70V lamps. I assume they get the
>70V by half wave rectifying the 120VAC line.

That would give you ~85VAC. It also might be prohibited because of the
unpleasant input waveform. Maybe they regulate the voltage fed to those bulbs.

>But why not just use a 120V
>lamp? I'm guessing that it MAY have something to do with being able to
>have a shorter filament making the light more of a point source and easier
>to focus. Is the guess correct?

Don't know for sure, but it wouldn't be surprising if there was an optimum
tungsten filament voltage which was between 12V and 120V. Newer cars with
42V electrical systems may benefit from this, to the extent they still use
incandescent lamps.

>Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
->>Test equipment, parts OLED displys http://search.ebay.com/_W0QQsassZspeff

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