50Hz AC Current Arduino calibration

Sampling the 50 Hz wave in arduino Uno board analog reading;


50 Hz means , 50 cycles in a second,
to complete one circle it takes 20 ms

if you sample the wave in normal arduino Anlogreading
then it take 116us to take a sample ,
time that take to reading between two value is 116us ;
so 20 ms it takes only 172 samples ..(approx)

That is  20/116 ;

so ,,,, we need to identify the phase before process the sampling ,,,

for(i = 0; i<172;i++){
data[i]=analogRead(A0);
} 

and get the average of the sample,

or you can but may be zero for AC signal , because AC wave have negative value too,

so to avoid that, takes max value of the average signal and multiply with root square , to get RMS value.