Phase voltage Measurement

[electronicsLearner77]

If i want to measure the 3 phase voltages and currents using simple microcontroller, i observe that there is a current transformer with output given to a micro controller i can read the currents. Do we have any similar devices to measure phase voltages up to 400V using micro controller, or any simple methodology can be used? Or it is like down converting from 400V to around 5V of the micro and calculate the phase voltages. I need not design as it is highly dangerous, but there is a circuit which is used for that, and i don't understand it.

 

[kellys_eye]

The usual method is to rectify the AC to DC and measure that (via attenuators).

You could use a transformer for isolation and step it down to something a lot safer, rectify it and measure that.

 

[hevans1944]

there is a circuit which is used for that, and i don't understand it.

Well, since you didn't bother to post an image (schematic) of the circuit, we don't understand it either.