CarlSereda@aol.com wrote:
>
> Hi list,
> I picked up the #52 Radio Shack screw in light bulbs (supposedly brighter
> than standard) for my TR4 dash - thinking I might replace all for brightness.
> After looking at some of the bulbs in my wiring harness I see most are marked
> Phillips (England) 12V 2.2W. Just curious - anybody know what these Radio
> Shack ones are in 'watts' (brightness) - on package they have 'Light Output'
> rated at 0.75MSCP. What's it all mean?
> ps; 'Average Life' is rated at 30 hours (seems kinda low since some of my
> working bulbs look 35 years old!)
There are varying ratings for bulbs. Watts, however, is the amount of
power consumed, rather than a measure of brightness (think of ratings
for illumination compared to watts consumed as a measure of the
efficiency of the bulb).
The common units of brightness are lumens and candlepower. I suspect
that MSCP stands for something like "mean standard candle power."
Meaning that the lamp you picked up would have an average brightness, at
its rated voltage, of 3/4 of one candlepower.
Average life is a determination of the expected life of the lamp under
the conditions described for its use--vibration during automotive use is
probably figured into the average life figure. But, you're right--it's
not very long. The actual life depends upon the quality of manufacture.
We had a considerable problem with GE halogen headlights installed on
some buses in the middle `90s. They were rated at 120 hours average
life, but most failed at 80-100 hours. Lamps from Wagner, meeting
similar specs, lasted hundreds of hours. I think "average life" ratings
are mostly a CYA spec.
Cheers, Carl.
--
Michael D. Porter
Roswell, NM
[mailto: mporter@zianet.com]
`70 GT6+ (being refurbished, slowly)
`71 GT6 Mk. III (organ donor)
`72 GT6 Mk. III (daily driver)
`64 TR4 (awaiting intensive care)
`80 TR7 (3.8 liter Buick-powered)
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