Re: converting for DCC


The post Adrian was questioning was:
If you cannot get satisfactory light output with the diode alone (to
low), then you could place a resistor in PARALLEL with the diode to
raise the light output.
Which is correct. The discussion centers around using less-than-full-wave
voltage (but more than half-wave) for a lamp. What you are doing is
providing some current when the diode is reverse-biased, in addition to the
current provided when the diode is forward biased. Some experimentation
will be required. This, of course, applies to powering incandescent lamps;
LEDs are a different ballgame. For cheapness, this would be a good
approach, but I agree that voltage rectification, filtering, and regulation
would provide the ultimate in track-powered constant, flicker-free lighting;
however, the power-up surge demand also needs to be considered. As well, it
depends on the size of fleet to be retrofitted, and the patience of the

For flicker free lighting, see also Rapido's battery-powered LED coach
lighting; very nice, track-power-independent, but be prepared to buy
batteries and change them fairly often (I get 15-30 hours of on-time); as
LED technology continues to evolve, producing more and more light per
milliwatt consumed, the Rapido approach will be even more practical. I have
quite a few of these cars, and since I'm presently building-not-running, the
batteries last a long time <grin>. Time will tell if I tire of
battery-swapping or not.

Blair Smith

Philippe said:
but if I were you, I'd watch out before putting resistors in parallel to
LED's or lamps. You must know maximum forward amperage allowed across the
diode >or the filament before doing this.

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