Carlos E. R. wrote:
The Sunday 2008-02-17 at 15:09 -0800, Randall R Schulz wrote:
So the RMS voltage and the resistance allow you to compute the average power over a full cycle. (Note that power is voltage squared divided by resistance and that this is the real reason that RMS is the way to compute the average power dissipation in a resistive circuit.)
For power you have to consider the power factor, the cosine of the phase angle - which for a resistor is 1, of course.
But if you have an instantaneous power function and apply the RMS calculation to that, you'll get a value with no physical meaning.
which is why I said the first day that I don't know how good are those measurement gadgets when applied to a swith mode power supply.
Here:
Search for the ADE7756AN (Active Energy Metering IC with Serial Interface)
-- Cheers, Carlos E. R.
It looks as good as the designer that uses it, besides a switch mode supply still converts the mains to DC, and smoothed before switching it through a ferrite core transformer. There are rules about sending high frequencies back up the mains supply. Both the power going in and out to MB is buffered so to speak. Dave -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org