Concept: capacitive pressure sensor, a capacitive pressure sensor converts the measured power output with a certain relationship between the use of a pressure sensor. Working principle: it typically uses a circular metal thin film or metallized film as an electrode of the capacitor, when the film is deformed by the pressure felt, the capacitance formed between the film and the fixed electrode is changed by the voltage measurement circuit to output a signals a certain relationship. Capacitive pressure sensors are extremely pitch change type capacitance sensor, can be divided into single capacitive pressure sensors and differential capacitive pressure sensor type: single capacitive pressure sensor consists of a circular film and fixed electrodes. Films deform under pressure, thereby changing the capacity of the capacitor, the sensitivity area and pressure substantially proportional and inversely proportional to the film tension and the fixed electrode film to film distance. Fixed electrode of another type takes a concave spherical shape, the diaphragm fixed to the periphery of the tensioning plane, diaphragm available metallised plastic layer is made of a method. This type is suitable for measuring low pressure, and a higher overload capacity. You can also use a single capacitive pressure sensors with moving piston diaphragm made of extremely high pressure measurements. This type can be reduced directly to the pressure receiving area of ??the diaphragm, in order to improve the sensitivity using a thinner diaphragm. Also with a variety of compensation and protection unit, and an amplifier circuit as a whole package together, in order to improve noise immunity. This sensor is suitable for measuring dynamic pressure and for aircraft telemetry. Single capacitive pressure sensor as well as microphone type (ie, microphone type) and stethoscope type and other types. Differential capacitive pressure sensor diaphragm on its pressure-receiving electrode is located between two fixed electrodes to form two capacitors. Under the effect of pressure increase in the capacity of a capacitor and the other is correspondingly reduced, the measurement result output from the differential circuit. It fixed electrode is metallized layer on the glass surface a concave curved made. Overload protection diaphragm without being concave rupture. Differential capacitive pressure sensor capacitive sensitivity than single, good linearity, but more difficult to process (especially difficult to guarantee symmetry), and can not achieve isolation measured gas or liquid, it is not appropriate to work in a corrosive or impurities in the fluid.