i'm trying to make a current sensor based on an op-amp differential amplifier with a unity gain (all resistors are equal so to have the best CMRR.)
The output of the op-amp differential amplifier will be linked to an ADC so that I can capture the voltage drop across a shunt resistor and make some processing .
the design i'm planning to implement is this one as published on EETIMES:
My questions are :
1)-Are there any practical consideration that I might be missing for this this circuit to work well .(i see in a lot of practical designs (for other circuits) some additional capacitors that are linked to terminals , diodes ... )
2)-I now know that this design has a draw back which is low input impedance ,can any one explain to me the impact of that on the design .
3)- for solving this problem of input impedance , can we consider increasing the values of the resistors R1,R2,R3,R4 .