Load Cell / Strain Bridge

A load cell is a Wheatstone bridge rated in mV/V: at 10 V excitation a 2 mV/V cell gives just 20 mV at full load. That tiny signal is why you need an instrumentation amplifier before the ADC.

Theoretical resolution only — real systems are limited by amplifier noise, thermal drift and mechanical creep, typically to a few thousand usable counts regardless of ADC bits.