Re: TDC DC

[P3D Sandman <sandler@xxxxxxxxxxxxxx>]

>Straight full-wave rectification plus a capacitor would yield about 160 VDC.
>A  suitable dropping resistor between the rectifiers and the (parallel) 
>capacitor would yield 120VDC (w/o flicker) and low bulb-surge voltage, 
>but might be rather sensitive to bulb-to-bulb variation without adjustment
>when bulbs are changed.

Ok, lets deal with this issue.  The full wave rectification will yield
higher than 120 V Peak to Peak (Why, because the 120 is RMS not peak to 
peak)

RECTIFIED SIGNAL
_   _   _   _  <- Greater than 120
 \ / \ / \ / \ 
  |   |   |    <- approx 0

Ok now add a capacitor across the leads

-------------  <- 120


If you add the capacitor across the bulb...same effect (ignoring
wire resistance and cap exactly, the same diagram).

I personally think the resistors are not needed/wanted (extra-heat). You
really just want a bigger cap.  Wire resistance is enough to damp any
oscillations that will occur between bulb and supply on start up (they
won't matter anyway).

Sandler


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