Optical and Magnetic Rotary Encoders are electromechanical feedback devices that measure angular displacement, shaft position, and rotational velocity by converting shaft movement into digital or analog electrical signals. Optical encoders pass light through a etched glass disc to photo-detectors for high accuracy and resolution, whereas magnetic encoders sense changes in magnetic flux over a magnetized disc for superior resistance to shock, vibration, and contamination. Key hardware features typically include precision stainless steel shafts, heavy-duty ball bearing pairs, absolute multi-turn gear trains or incremental quadrature track discs, flange-mount or hollow-shaft clamping options, and industrial bus connectors.