Dan,
The GE small lamp catalog actually lists all the information from
voltage to current draw to candlepower. While I'll admit that most car
accessories are listed as 12V when we are really dealing with over 14
volts, lamps are given their true rating, or none at all. The package
doesn't usually say anything but the number.
I am only extrapolating from the fact that I took one lamp that says #52
out of my Healy, and another that said 12V, 2.2W out of my MG. I'm
pretty sure that if the spec sheet says 12V, it is 12V. The problem is
that the lamp with the specification doesn't have a number on it.
Jack
> ----------
> From: DANMAS[SMTP:DANMAS@aol.com]
> Sent: Wednesday, April 29, 1998 3:37 PM
> To: paul.hunt1@virgin.net; Feldman, Jack (Jack)
> Cc: mgs@autox.team.net
> Subject: Re: Dim Panel Lights
>
> Buying a 12 volt light bulb is like buying a 2 X 4! Just as a 2 X 4
> is not
> actually 2" X 4", a 12 volt light bulb may not be rated at 12 volts.
> 12 volts
> is the nominal value, just as 12 volts is the nominal value for the
> voltage of
> a car battery. In good conditiopn, a car battery will produce 12.6
> volts. As
> an example of light bulb ratings, take the very common 1157 bulb, used
> in
> almost every American car (at least in the older American cars). It
> is a dual
> filament bulb, one filament rated at 27 watts and the other filament
> rated at
> 8 watts. If you look up the manufacturers specifications, you will
> find that
> the brighter filament is rated at 2.1 amps at 12.8 volts, while the
> other
> filament is rated at 0.59 amps at 14 volts.
>
> If you go to an auto parts store to buy one, if it says anything at
> all on the
> package, it will say 12 volts. For 99.00% of applications, that is
> close
> enough. If you really need to know how much current it draws, you
> will have
> to get the spec sheet and find out at what voltage the 27 and the 8
> watts were
> rated at. Then you will need to know what voltage it will be seing n
> your
> application, which is very hard to do, as the voltage in a car varies
> from as
> low as 11+ volts to as high as 15 volts. In a car with a properly
> functioning alternator, the voltage will be around 14 volts most of
> the time.
>
> If you go to the manufacturers spec sheet, as the gentleman who raised
> the
> question did, you may find the 12 volt, 2.2 watt bulb you have is
> actually
> rated at 14 volts. Or 12.8. Or 16. Or whatever.
>
> Dan Masters,
> Alcoa, TN
>
> '71 TR6---------3000mile/year driver, fully restored
> '71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion
> - see:
> http://www.sky.net/~boballen/mg/Masters/
> '74 MGBGT---3000mile/year driver, original condition - slated for a V8
> soon
> '68 MGBGT---organ donor for the '74
>
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