Re: [CAD_CAM_EDM_DRO] Re: looking a power supply for gecko

In a message dated 28-Feb-02 23:34:20 Central Standard Time, wanliker@...
writes:

> .
>
> 1.414 times a given transformer voltage will equal the output voltage
> of
> a simple bridge rectified, capacitor filtered supply. (the type we
> use).

Though I flunked "junior circuits", in my E.E. course of study in '65, I have
done much more successfully in electronics and fiscal luck than 99% of my
classmates. That was not a "boast" but a preface. Still, I consider myself
a "dum' ol' boy" when it comes to mathematical wisdom. Yet, I feel compelled
to point out this "SQR(2) rule" is accurate ONLY with "no load". That is, by
the time you load-up the "simple bridge/filter circuit" to the rated
current-load of the transformer, the effective "average" D.C. will be very
close to the RMS voltage of the transformer! A linear voltage-regulator set
for a D.C. output equal to the AC RMS rating of the transformer will probably
pass "chopped" D.C., unless the filter-capacitor is at least 1500 or 2000 µF
per amp, and probably even then! Surely there are a few "E.E's" in here who
can confirm this? You "chop" your D.C. input to fancy circuitry like
chopper-drives, and you will start getting very interesting noises coming
from motors and computers and such in other States of the nation! Seriously!
Lotsa luck! Jan Rowland, Old Troll


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