-=> Roy J. Tellason said to Jasen Betts
 -=> about "VEHICLE LED'S" on 08-29-03  20:01.....

 RJT> Another easy fix for that is to use a current-regulator.  Something
 RJT> like an LM317 (?) and a resistor,  in line with the lamps...

Let's see... you'd have to drop 1.25v across the resistor, and
there needs to be at least 2 volts input/output differential, so
you'd have to generate more than 3+ volts above the bulb voltage.

Personnally I think a constant voltage regulator would be better.
You would only have to supply about 2 volts above the lamp voltage.

There is another problem, that most cycle generators put out AC,
so you have to add in the drop across a rectifier to the above
losses.

Even with a capacitor input filter, the impedance of the usual
cycle dynamo is too high to charge the cap to the peak voltage,
as you can do with a mains supply to offset the diode drops.

The best form of regulation would be a shunt regulator to bleed
off some of the current when the voltage got too high for the
bulb. Unfortunately this would increase the load on the dynamo.

From Greg Mayman, in beautiful Adelaide, South Australia
   "Queen City of The South"    34:55 S  138:36 E

... Do not merely believe in miracles, rely on them.
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