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The Structure Principle Of The Capacitance Pressure Transducer

Jan 29, 2019

Description of the structure principle of the capacitance pressure transducer

Capacitance pressure transmitter is a high-precision intelligent instrument. It adopts a mature capacitive sensor with long-term stability and high reliability. Through the digital technology, the temperature and nonlinearity of the sensor are compensated, which greatly improves the accuracy and range ratio of the sensor.

The pressure transmitter of the condenser pressure transmitter manufacturer adopts a simple, sturdy and extremely stable variable capacitor form. The variable capacitor is composed of a diaphragm on the pressure chamber and an insulated electrode fixed on the pressure chamber. When the pressure changes, the diaphragm will have a slight warp deformation, which changes the spacing between the two poles. A unique detection circuit is used to measure small changes in capacitance, and linear processing and temperature compensation are performed. The sensor outputs a DC voltage or current signal that is proportional to the measured pressure. The combination of compact construction, high-performance materials and advanced inspection circuitry gives the capacitance pressure transmitter a high performance.

capacitance pressure transducer

The capacitance pressure transmitter is divided into a pole-distance change type and an area change type. When the change of the measured parameter directly affects the magnitude of the capacitance through one of the three conditions, the change of the capacitance is equivalent to obtaining the measured value. The size of the parameters, capacitance pressure sensors are often used in the variation of the pole pitch. The pressure causes a slight displacement of the movable member of the sensor, that is, the measuring diaphragm plate, causing a change in the capacitance formed by the fixed plate.

In order to improve the sensitivity and reduce the nonlinearity, most pressure sensors use a double-capacitor plate with a poor structure. The movable plate is located between the two fixed plates and equidistant from the two fixed plates. When the pressure moves the movable plate upwards. When it occurs, the differential capacitance is increased and decreased.

Compared with the single-capacitance pressure sensor, not only the sensitivity is improved, but also the nonlinear error is reduced. It can be seen that the differential capacitance pressure transmitter is superior to the single-capacitance pressure sensor.

Capacitance pressure transmitters have higher stability than other similar products. Unlike other sensors such as metal strain gauge sensors, capacitance pressure transmitters have minimal creep, aging and temperature effects. Almost all unfavorable factors have less impact on the stability of capacitance sensor output than other forms of sensors.