/diy/ - Do It Yourself

If I'm measuring the voltage across a current shunt, is there a reason to use an instrumentation amplifier instead of a simpler differential amplifier? I'm wondering if the low-impedance of the shunt will mean I won't have an issue since the differential amplifier's impedances will be much higher. But since there's a very likely situation where the current through the shunt is 0A and the output impedance of the source-follower would be really high, I can't say whether the differential amp would read properly.