A speed sensor is a sensor that converts the speed of a rotating object into a power output.
The speed sensor is an indirect measuring device that can be manufactured by mechanical, electrical, magnetic, optical and hybrid methods. According to the different signal form, the speed sensor can be divided into analog and digital, sample as below:
The output signal value of the analog speed sensor is a linear function of the rotational speed, and the output signal frequency of the digital speed sensor is proportional to the rotational speed, or its signal peak interval is inversely proportional to the rotational speed.
The wide variety and wide range of speed sensors is due to the extensive use of a wide range of motors in automatic control systems and automation instrumentation, and strict requirements for accurate measurements of low speeds (such as one turn per hour), high speeds (such as hundreds of thousands of revolutions per minute), steady speeds (such as errors only) and instantaneous velocities in a number of situations. The commonly used speed sensor has photoelectric type, capacitance type, variable reluctance type and speed measuring generator and so on.
Schematic diagram of the speed sensor as below: