A string potentiometer is a transducer used to detect and measure linear position and velocity using a flexible cable and spring-loaded spool.
String potentiometers are composed of four main parts: a measuring cable, spool, spring, and rotational sensor.
[citation needed] Engineers designed and built these units originally to measure movement of airplane parts as they were cycled during testing.
[citation needed] Common applications include: Hydraulic cylinders are used in many industries such as forklifts, cranes and aerials, material handling, die-casting, oil and gas, robotics and automation.
The string potentiometer may be connected as a three-wire tapped resistor (voltage divider), in a control circuit, or may be packaged with electronics to produce a measurement signal in a useful form, such as a variable voltage 0-10 VDC, variable current 4-20mA, pulse encoder, Bus (DeviceNet and Canbus) and RS-232 communications.