An encoder is a device used to sense position or orientation for active feedback and position control. There are two primary types of encoders: rotary encoders and linear encoders. Both detect and convert position into an electronic signal.
Rotary encoders convert the angular position or motion of a shaft into an electronic signal. These encoders are specifically designed for applications that require precise rates of rotation. Linear encoders are paired with a scale to encode position along a linear path. These encoders are widely used in applications that require accurate, high-speed movement along a fixed path.
Both encoders can either be absolute or incremental. Absolute encoders maintain absolute position even when removed from a power source and do not have a "home" position. Linear encoders, alternatively, require a reference point to report position at certain intervals. Both provide the same accuracy, but absolute encoders are more resistant to power or signal loss.