I'm building my own digital meter in order to upload the data to a SQL database; up until now I know that there are several parameters being measured into a digital watt-meter:
volts, current, apparent power, instantaneous power, actual power, power factor
However, I still have to understand which one of these is the real value used to increase the counter on both devices. To be more precise with my question, old analog meters couldn't do all these calculations, and still they worked out as intended. However with, no linear loads being more and more common, I'm guessing the power factor in a common house would be hanging around .7 or .8 so how does this change in the type of load would affect the measurement in a digital vs analog watt-meter?
My first guess would be that analog meters measure REAL POWER, but I can't be so sure about digital smart meters.
How do they work?