An optical encoder is a device that converts the position or movement of an object into an electrical signal. It uses light to detect changes in position, typically employing a light source and a sensor. When the object moves, it interrupts or reflects the light, allowing the encoder to determine its position or speed. These encoders are commonly used in various applications, such as in robotics, industrial machinery, and computer peripherals. They provide precise measurements, making them essential for tasks that require accurate control and feedback, such as in automated systems and CNC machines.