need help with the measurement of AC

[rakky]

I am working on a project that requires the measurement of AC and feed it to the ADC of ATmega16.I have tried measuring the current with CT but it has been tiresome to exactly calibrate the CT.I need to measure current in the range of 0-10Amp. Since,the load can vary in my case,the current sensing ckt must be able to sense the current in the given range.I have been stuck in this part and is unable to proceed further.

I have thought about hall sensors but they are difficult to find in my place.

Is there any method to measure AC except these two???

 

[magvitron]

you can use current sensors for the thing. safer and effective way.
**broken link removed**
https://in.element14.com/allegro-mi...5cb-t/ic-current-sensor-25a-16soic/dp/1791413

 

[crutschow]

If you are measuring main's current, you need isolation, and that's typically done with a current transformer or Hall Effect device.

A more complex way is to directly measuring the current using a resistive shunt with a circuit powered from and in common with the power line. The AC signal representing the current is then transmitted using an isolation barrier such as a transformer or optical isolator.

 

[ronsimpson]

What CT circuit have you tried?

 

[rakky]

I have a CT with turn ratio of 30:5.I am using 5ohm,5watt resistor in its secondary side.I have tried finding the offset but it is non-linear.

 

[crutschow]

I have a CT with turn ratio of 30:5.I am using 5ohm,5watt resistor in its secondary side.I have tried finding the offset but it is non-linear.

What offset? CT's have no DC offset. Are you referring to offset from the AC to DC conversion circuit? If so post the schematic.

 

[alec_t]

I have tried measuring the current with CT but it has been tiresome to exactly calibrate the CT.I need to measure current in the range of 0-10Amp.

CT calibration should be straightforward using a few known resistive loads. Even if you don't use a CT you will probably still have to calibrate something. How accurate must your measurements be?

Edit: 30:5 (i.e. 6:1) seems a very low turns ratio for a CT?

 

[elec1]

You can use a shunt resistor for this problem.