Re: LED Headlight and generator?

Jim Adney wrote: 
Use those two LEDs connected in series behind a Shottky bridge: Double
light output, less flicker. Possibility to smooth out the remaining
flicker with a fat low-ESR capacitor. Possibility to ad a Standlight
capacitor in parallel to one of the LEDs.


We have to keep in mind that even when the polarity is in the right
direction, no current flows at all until the voltage exceeds the total
forward voltage drops of the components. If you draw yourself a nice
AC waveform, you will see that the effect is to produce shorter and
shorter light pulses. The integrated effect is less light. The
capacitor really won't smooth this out, unless you also add in a
resistor, which wastes power....

The LED uses power, which means it must have a resistive component to its impedance when it's on. I haven't bothered to check the magnitude of the respective components, but if the capacitor is sized relative to the resistance in the LED, you should get smoothing.

--
Dave
dvt at psu dot edu

.

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