A Position Sensor is any device that allows position measurement. It can either be in the form of an absolute sensor or can be either linear or angular. There are many types of position sensors each with their own application. Some examples include inductive non contact position sensors, linear variable differential transformers, potentiometers, eddy current sensors, grating sensors, hall effect sensors and rotary encoders. A Rotary encoder is an electro-mechanical device that converts the angular position or motion of a shaft or axle to an analogue or digital code and the output provides information about the motion of the shaft. This information is normally processed elsewhere into information such as speed, RPM, distance and position. The output of absolute encoders shows the position of the shaft which makes them angle transducers. Rotary encoders are used in many applications that require exact and precise shaft unlimited rotation which includes robotics, special purpose photographic lens, industrial controls and computer input devices such as the mouse.