In this application note we will look how to convert AC voltage to DC voltage how to measure it in our Arduino. An AC voltage measurement is needed to calculate real power, apparent power and power factor. This measurement can be made safely (requiring no high voltage work) by using an AC to AC power adaptor.
Here we are using 12V -0-12 V transformer which converts 230 V AC to the 12V AC,So whenever we are providing 230 V to the transformer we will get 12 V AC and the Vp (voltage peak) would be 16.968V (i.e 12*1.414) and Vpp (voltage peak-peak) would be 33.936 V.