Position measurement by potentiometer is based on changes in the resistance in an electrical conductor as a function of its length (Figure P 14). These days, position measurement by potentiometer is mainly performed with potentiometers featuring conductive plastic, which tend to offer better resolution than wire potentiometers (up to 0.01 mm). Advantage: high precision at a low price; disadvantage: these too are subject to wear.
Figure P 14: Layout for a linear potentiometer