An absolute encoder is a type of rotary encoder that provides a unique position value for each shaft position. Unlike incremental encoders, which only detect movement relative to a starting point, absolute encoders always know the exact position of the shaft without needing to return to a reference point. They are commonly used in applications requiring precise position tracking, such as robotics, CNC machines, and industrial automation. Absolute encoders can be optical, magnetic, or capacitive, and they output position data in digital or analog form, ensuring reliable and accurate control.