What type of encoder provides exact position feedback even during a power failure?

An absolute encoder is designed to provide precise position feedback regardless of whether power is supplied or not. This capability is crucial in applications where knowing the exact position of a component is necessary, even during power loss. Absolute encoders work by assigning a unique binary code to each position within their range of motion, thus maintaining positional information at all times.

During a power failure, unlike incremental encoders, which only indicate movement from a reference point and lose positional information when power is cut, absolute encoders retain their last reported position without the need for recalibration when power is restored. This makes them ideal for applications requiring high reliability and accuracy in position sensing after power interruptions.

Rotary encoders and linear encoders are types of encoders that can be either absolute or incremental, but without the absolute designation, they may not retain positional data during power loss. Thus, the specific designation of an absolute encoder is necessary to emphasize its unique capability for exact position reporting at all times.