I am trying to read a current waveform from a shunt resistor series with the power line.
Using a full bridge rectifier, I got the following waveform:
The waveform was sampled every 2 millisecond using an Arduino. Upon fourier analysis, I found that it contained a 100 Hz signal.
Since the supply frequency is 50hz in my region and being rectified the waveform is 100 Hz.
But I want to use opamps as a precision rectifier to get smaller voltages than the diode drop. I am using the below configuration. I tested the configuration by setting the input as positive and negative DV voltage from a battery and the negative DC was given as positive DC by the opamp.
This is the current waveform obtained I got from the opamp:
The zero point of the waveform keeps changing periodically.
Is this a problem with the opamp configuration, or is there a better way to do full wave rectification using a single supply opamp?
EDIT: I meant to use 10 kiloohm resistors, not 10 ohm. 240-24 volt step down transformer signal divided between 10kiloohms and 1 ohms resistor UPDATE: The opamp configuration was working perfectly fine. The original signal contained the zero point oscillation.The full bridge rectifier's output was not showing this output because it was not strong enough to overcome the diode voltage drop. After increasing the voltage i was able to see the same signal from the full bridge rectifier as well. Phew!!!! Finding out ground truth is very important.