An incremental encoder is a sensor of mechanical motion. It translates motion (such as speed, direction, and shaft angle) into electrical signals. Resolutions can be relatively small - less than 50 pulses per revolution - to very high resolution (over 100,000 pulses per revolution). An incremental encoder is used when retention of absolute position upon power loss is not required. Examples include velocity control and simple point-to-point applications. As the code disk rotates in front of the stationary mask, it shutters light from the LED. The light that passes through the mask is received by the photodetector, which produces pulses in the form of a quasi-sine wave. The incremental encoder electronics convert the sine wave into a square signal, ready for transmission to a counter.