Constantin:
Hi guys and gals,I hooked up the front end of my ADC to my oscilloscope and measured something interesting. Specifically, there appears to be a variable phase lag between the transformer for the voltage signal (ERA 0.08VA) and the current transformer (CR Magnetics CR8348-2500-N) as a function of load. Voltage always is lagging current.
That's the difference between an actual and an ideal transformer. With no load the transformer will approximate
an inductor in series with a resistor.
There may also be time delays in the measuring chain, which can be calibrated if you replace the transformer
directly with a resistive mains load like a tungsten bulb.