Electronics > Beginners
AC voltage measurement with a microcontroller
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b_force:
About isolation, it depends on the approach.
You can first isolate the measured signal or you can also get a interface isolation IC.
That means that you don't isolate the signal but the isolation is behind the ADC or ucontroller going to the rest of the system.
09d08:
I think I'll use a voltage to frequency converter like an LM331 with an optoisolator. A zener supply for the LM331 should suffice and provide isolation at a reasonable price. I'll draw a schematic when I get home.
RoadRunner:
One possible Way to have get 12V from your inverter transformer and use circuit something like i did for fun few year back with MSP430

https://www.circuitvalley.com/2015/01/true-rms-meter-microcontroller-mains.html
JS:
  Getting the clean AC to the µC is the hard part, then, once you get the AC to the µC ADC with the proper offset you should just sample it and do the math there, you don't even need to porvide enough bandwidth for the signal, I successfully build an audio vumeter with an arduino (9kSa/s max?) with decent response well over 20kHz.

  As said a transformer would be nice but then you have the problem of the linearity of the transformer. Other way would be to make a capacitive divider and a transformer to provide isolation, but then you need to characterize the caps, the transformer and the interaction between them.

JS
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