China sensor is an original that transforms the change of non-electric quantity (such as speed and pressure) into the change of electric quantity. According to the different non-electric quantity converted, it can be divided into pressure sensor, speed sensor, temperature sensor, etc. It is the parts and accessories of measuring and controlling instruments and equipment. The speed sensor is mainly used to detect the rotating speed of electric vehicle motor. There are three commonly used speed sensors, respectively electromagnetic induction type speed sensor, photoelectric induction type speed sensor, Hall effect type speed sensor, all adopt non-contact measurement principle, in order to enhance the safety of detection, improve detection accuracy.