Wide range and high precision current measurement
Simply bypassing a current shunt requires an impractically low resistance switch, when the currents start to get into the amps.

Far better is a current routing switch as shown below. Each switch element can now be any resistance without affecting the metering accuracy, it only affects the voltage drop across the meter. This means you can choose (for instance) a power FET for SW1, and an analogue multiplexer for SW3 and SW4. You could even use BJTs, which would not work at all well as low resistance switches, but work just fine for current steering.







simulate this circuit &ndash; Schematic created using CircuitLab