A rotary encoder is an electromechanical device that converts the angular position or motion of a shaft into an electrical signal. It is commonly used in various applications, such as robotics, industrial machinery, and consumer electronics, to provide precise control and feedback about the position of a rotating object. There are two main types of rotary encoders: absolute and incremental. Absolute encoders provide a unique position value for each angle of rotation, while incremental encoders measure the change in position from a reference point. Both types are essential for applications requiring accurate motion control and positioning.