Re: lights (nay audi content)

[ti@amb.org (Ti Kan)]

Bob Virtual wrote:
> I'm thinking of replacing the incandecent light bulbs
> with LEDs. The only thing I planned was putting in a
> simple resistor per LED. But how well does that cope
> with the flucuating voltage, power surges & spikes,
> etc., that come with automotive electrical system?

James M. De Arras writes:
> Best thing would be a constant current source, I'm not sure if they make
> them in the needed range, but they had 1.2ma ones a decade ago, so they
> ought to have them.

Not necessary.  LEDs (except the blue ones) can typically operate fine
over a fairly wide range of currents.  The voltage drop across the LED
is basically constant (one volt or so), so the series resistor is simply
a current regulator.  A car's electrical system normally operates somewhere
between 12V and 14.5V and that's not too much of a big range.  The key is
to use an appropriate value series resistor for the LED.

You'll find that there are already plenty uses of LEDs in cars.

-Ti
96 A4 2.8 quattro
84 5000S 2.1 turbo
80 4000 2.0
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