How to measure ac current using opamp.

[shashavali_m]

Hi all , yours Dear shashavali is back again asking u r help.
i need the schematics used to measure ac current using opamp and the output of the opamp is fed to the analog inout pin of the microcontroller.
please help me

 

[flatulent]

You have several choices.

1. A series resistor. Measure the voltage drop across it.

2. A current transformer.

3. A Hall effect sensor.

 

[instruite]

Normally opamp is used in following configuration to measure the current
**broken link removed**

If you want to measure AC current Which I assume goes to negative value also
then also configure non inverting pin as adder (see circuits for opamp as adder) which will make the 0A level to your added voltage hence you will be able to measure +ve as well as -ve side of current

 

[Baljeet]

hi,
you can use half wave precision amp, feed its o/p to low pass filter
and finaly you get a constant dc voltage, which can be easily be measured.

bye