> I think your getting into too much of the specifics of this application
(I'm
> having to explain things about the application, that have no bearing on
what I'm
> asking).  Assuming that I don't care about how much current draw there is
to a
> given load, should I use an RMS method, or just simple Averaging to
calculate
> the voltage going to the transformer?

RMS.

I did a quick calculation to see what a reasonable sampling rate is.
Suppose you sample at 1.8KHz.  That gives you 30 samples per cycle.  You
can think of the cycles as being broken into 30 chunks, with each chunk
assumed to have a constant voltage.  The energy into a resistive load will
be proportional to the square of the voltage for each chunk.  For a 60Hz
sinusoid, a chunk at the peak of the waveform will contain about 6.7% of the
energy of the whole cycle.  This is the worst case error due to an
instantaneous voltage transition at the worst time.  The error goes down
proporitionally as the sampling frequency goes up.  If you can manage 5KHz
sampling rate then the maximum energy in any one time slice is 2.4%.  How
accurate do you need it?


********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, olin@embedinc.com, http://www.embedinc.com

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listserv@mitvma.mit.edu with SET PICList DIGEST in the body