#### ste2006

##### Advanced Member level 4

I am probably missing something obvious but i am looking to design a circuit to calculate true RMS power for an AC mains supply,

Would i be correct in saying the following would work,

1) Measure true RMS voltage for one complete cycle using resistor divider

2) Measure true RMS current for next cycle using Current Transformer

3) Multiply these values together to then give True RMS Power??

The mains frequency is 50Hz and i only want an updated value every 25 cycles so would the above work or does the voltage and current have to be sampled at the same time??

Thanks in advance,