Displacement sensor is also known as linear sensor, displacement sensor is converted to electricity. Displacement sensor is a device that belongs to the metal induction linear sensor is used to convert various measured quantities to power it is divided into inductive displacement sensor, capacitive displacement sensor, photoelectric displacement sensor, ultrasonic displacement sensor and hall displacement sensor.

In the conversion process, there are many physical quantities (such as pressure, flow rate, acceleration, etc.) often need to transform as the displacement, then the displacement transform into electricity. So the displacement sensor is a kind of important basic sensor. In the process of production, displacement measurement generally divided into two physical dimensions and mechanical displacement measurement. Mechanical displacement including linear displacement and angular displacement. According to the measured variable transformation, different kind of displacement sensor can be divided into analog and digital two kinds. Analog type can be divided into physical properties (such as spontaneous electric) and structured two kinds. Displacement sensor is commonly used in the majority with analog structured, including the potentiometer displacement sensor, inductive displacement sensor, selsyn, capacitive displacement sensor and electric eddy current displacement sensor and hall displacement sensor, etc. An important advantage of digital displacement sensor is to facilitate the signal directly into a computer system. This kind of sensor has been developing rapidly, the application is becoming more and more widely.