-=> Mike Ross said to Greg Mayman
 -=> about "VEHICLE LED'S" on 09-02-03  21:59.....

 MR> The impedance is pretty low, in fact I've thought about adding an AC

Somewhere I read that the inductance of the windings (and hence
the impedance) was relatively high.

As the dynamo turned faster and generated more voltage, the
frequency would also go up, causing a greater voltage drop across
the internal inductance to give a more or less constant voltage
to the lamp.

 MR> capacitor across the lamp to increase the power factor and thus extend
 MR> the power band somewhat. It's kind of like a resonant circuit where

It's _exactly_ like a resonant circuit, that will have maximum
effect at one particular frequency.

 MR> the capacitor supplies power when the generator goes through zero thus
 MR> keeping the filament more fully lit on average by increasing the

No it won't since the capacitor will take power from the
generator when the generator output is at a peak. If the waveform
that comes out of the dynamo is more or less a sine wave, adding
a capacitor will not change the waveform to any great extent,
apart from removing some of the harmonics.

 MR> voltage across the lamp somewhat. Or more simply by cancelling the
 MR> series inductive reactance as seen by the lamp. I haven't taken any

It will cancel only at one particular speed/frequency. If it
works, the light would brighten up at that speed, but be
noticeably dimmer at higher speeds due to the low pass filter
effect of the capacitor.

 MR> Not on the dynamo... ME!!!   Mr. Motive Source!!!

The load is first of all on the dynamo, since that is the only
thing that the circuit is drawing power from.

Then it would also be indirectly on you, unless you're coasting
downhill ;-)

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

... If practice makes perfect, and nobody's perfect, why practice?  ...
___ Blue Wave/386 v2.30

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