The principle of the pressure sensor is mainly based on different sensing elements and

their working mechanisms, such as piezoelectric effect, strain gauge, diaphragm and

liquid column. Piezoelectric sensors take advantage of the properties of piezoelectric

materials that produce a change in charge or voltage when subjected to pressure, and

infer the pressure by measuring this change. Strain gauge sensors are based on the strain

characteristics of metal or semiconductor materials, and when subjected to pressure, the

strain gauge will deform, causing its resistance or capacitance to change, thereby measuring

pressure. The diaphragm sensor uses the deformation of the elastic film to measure the

pressure. When the film is subjected to pressure, it bends or deforms, and then obtains

the pressure value by measuring the change of resistance or capacitance. The liquid column

sensor measures the pressure by using the height change of the liquid when it is subjected

to pressure in the pipeline, and the height of the liquid column is proportional to the

pressure. These principles have applications in the pressure sensor, the pressure signal is

converted into an electrical signal through the sensitive element, and the signal processing

circuit is amplified, filtered, etc., and finally output in the form of analog or digital signals

to meet the needs of different application scenarios.