Hello, I have to use this circuit as part of a school project so I'm limited to this design and these components. The voltage regulator works as anticipated however the differential amplifier does not. Here it amplifies, by a factor of 10, the voltage drop across the shunt resistor R8 which is ~28mV. I'm having two issues with this however circuit however.
- The output of the LM324N on the simulation is 303mV but shouldn't it be 280mV since the gain is set to 10 by the 100k and 10k resistors ?
- When I physically replicate the circuit the output voltage of the LM324N is 562mV with all the same parameters as the simulation but the voltage across the shunt is 27.2mV.
How can I solve both problems ? I think that it may have something to do with CMRR and the input offset voltage which according to the datasheet is typically 2mV. I'm also new to all of this and I don't completely understand CMRR