I'm trying to measure a current that could vary from 50mA to 1A. I'm thinking I would just use a resistor on the negative side and an opamp to boost the voltage. But when I search for shunt all I get is big units for 50A+. If I search for small current measurement I get stuff for micro amps. Is there a shunt available for what I want? Does it have a special name? Any better way to measure that sort of current?