Types of displacement sensors

The main types of displacement sensors are linear displacement sensor, angular displacement sensor, photoelectric sensor, ultrasonic sensor and Hall effect sensor.

Linear displacement sensor is the most commonly used displacement sensor, and its working principle is to measure the position change of an object when it moves linearly, usually based on the change of resistance, inductance or capacitance. For example, the change of the position of the slider of the sliding rheostat will change the resistance value, so as to measure the displacement.

Angular displacement sensor is used to measure the change of rotation angle of an object, and usually adopts magnetic field, optical or mechanical means to measure the change of angle. For example, the photoelectric encoder measures the angle change by measuring the pulse generated by the light beam passing through the gap on the encoder disk.

Photoelectric sensor and ultrasonic sensor measure displacement based on photoelectric effect and ultrasonic propagation principle. A photoelectric sensor includes a light source and a photodetector. When an object moves between the light source and the photodetector, it will block or reflect the light, change the output of the photodetector, and then measure the displacement. The ultrasonic sensor emits ultrasonic waves, and then measures the time from emission to reception to calculate the distance or displacement of the object.

Hall effect sensor works based on Hall effect principle, and is used to measure the change of magnetic field to infer the position change of objects. The wheel speed sensor commonly used in automobiles, when the wheel rotates, the relative position change between the magnet and the sensor will produce voltage change, thus measuring the wheel speed.

The above are just some main types and working principles of displacement sensors. According to different application requirements and measurement environment, there are more sensor types and technologies to choose from. Each sensor has its unique advantages and limitations, so when selecting and using displacement sensors, it is necessary to flexibly select the appropriate sensor type and technology according to the specific measurement tasks and environmental conditions.