The Carey Foster bridge works on the principle of the wheatstone bridge (potentiometer)which can be used to measure fractional resistance.
The potentiometer is a position tranducer. It forms a resistance divider, proportional to position.
resolution of petentiometer
A: A potentiometer is a manual device to change the resistance A thermistor changes as a function of environment temperature
A voltmeter is used to measure voltage. A potentiometer is used to vary the amount of resistance in a circuit - it has nothing to do with measuring.