I've been trying to build a shunt resistor based current sensor using OP07. I've particularly chosen this because of its ultra low offset value. Its configured to be in differential mode as shown in the circuit below.
The output is to be scaled from milliVolt range to 5v where the full scale deflection is set to be 5A -> 5v.
The problem I'm facing is the output is not scaling with the change in current. It gives out random values which almost has no relation with the input. I've tried the circuit with low side sensing, high side sensing along with Non-inverting configuration.. All the circuits are tried separately and the output is not the expected one. Please help me understanding the issue. Again to test if opamp is damaged, I tried voltage follower and it was working as expected and I tried with common mode(both inverting and non-inverting shorted to ground), the output comes to be saturated. Is this behavior expected?
Thank you for the help!!