Depending on the position of the moving part ( grinder ), the electrical resistance between the grinder and the ends changes. If you switch the encoder as a voltage divider , you get an electrical voltage that changes relative to the position.
The sensor is calibrated in order to be able to assign a certain voltage to a certain position.
Mechanically, the following variants are common:
- The resistor is embedded in a piston, the grinder is mounted on a cylinder that moves in the piston
- The resistance is a toroid -Spule of resistance wire
- the resistance track is circular, made of conductive plastic and allows rotation angles over 360 °
Modern linear potentiometers as well as rotary potentiometers are made with traces of conductive plastic (conductive plastic). This solution not only achieves a significantly longer service life than wire potentiometers, but the high-quality mixtures also enable use in humidity and high temperatures such as 175 ° C.
Areas of application for such systems are often found in motorsport for spring travel monitoring on shock absorbers or gear controls, on machine tool tables or on industrial robots . The servos common in model making also use a potentiometer attached to the rotary axis to measure angles.
- See also