Encoders are used in robotics and automation to measure the rotational movement of an object. They typically provide a digital output that can be used to determine the angular position, velocity, or acceleration of the object. Encoders come in a variety of forms, including optical, magnetic, and inductive. The most commonly used encoders are optical encoders which use an LED array to measure the rotation of a shaft. The LED array is usually coupled with a computer-readable disc that contains patterns which can be read by a computer and converted into a numerical value. Encoders are often used in motion control applications, where their speed and precision can be used to measure the speed and position of an object.