The pressure sensor can be classified into strain type, piezoresistance type and capacitance type according to the working principle; It can be divided into gauge pressure sensor, differential pressure sensor, etc. according to the measuring pressure type; It can be divided into analog signal sensor and digital signal sensor according to the type of output signal.

The pressure sensor can be classified into strain type, piezoresistance type and capacitance type according to the working principle; It can be divided into gauge pressure sensor, differential pressure sensor, etc. according to the measuring pressure type; It can be divided into analog signal sensor and digital signal sensor according to the type of output signal. The details are as follows:

Classified according to working principle:

Strain-type pressure sensor: metal strain gauge or semiconductor piezoresistance element is used. When the pressure acts on the elastic sensitive element, the elastic element deforms to change the resistance value of strain gauge. The pressure value is obtained by measuring the resistance change. With mature technology, firm structure, stable and reliable performance, it is widely used in the industrial field.

Piezoresistance pressure sensor: the core sensitive element is silicon piezoresistance chip. Based on the piezoresistance effect of silicon, the resistivity of monocrystalline silicon material changes under pressure, and the pressure deformation of silicon diaphragm changes the resistance value of the integrated piezoresistance to measure the pressure. This type is small in size, low in power consumption and high in sensitivity, and widely used in modern electronic equipment, automobile, medical treatment and other fields.

Piezoelectric pressure sensor: using the piezoelectric effect of piezoelectric materials such as quartz crystal and piezoelectric ceramic, polarization phenomenon is generated inside the stressed deformation, charge is generated on the surface, and the pressure signal is converted into charge signal for output. It has very high frequency response and is mainly used for dynamic pressure measurement such as explosion, combustion and high frequency vibration.

Capacitive pressure sensor: two parallel electrode plates are formed by metal or plated metal diaphragm. The diaphragm is deformed under the action of pressure, which causes the distance between two electrodes or the effective area to change, and the capacitance value changes accordingly. The pressure is measured by measuring the capacitance change. With high sensitivity and good dynamic response, it is widely used in low pressure, micro pressure and differential pressure measurement.

Resonant pressure sensor: measure the pressure by changing the natural frequency of resonance elements such as tuning fork and quartz beam. Its precision is very high, but the structure is complex and the cost is high. It is often used in laboratories and standard equipment with high precision requirements.

Ceramic piezoresistance/thick film pressure sensor: it is an improved piezoresistance/strain sensor. It uses high tenacity ceramic as the direct pressure sensing film, and uses thick film printing sintering process to deposit the resistance network on the back of the ceramic film. It is resistant to corrosion, abrasion and high temperature and is applicable to pressure measurement in harsh environment such as chemical industry and medical sterilization.

Classified by type of measured pressure:

Gauge pressure sensor: measure the pressure relative to the atmospheric pressure, i.e. the difference between the pressure of the measured object and the local atmospheric pressure. It is one of the most common pressure measurement methods, commonly used for pipe pressure, cylinder pressure, etc.

Differential pressure sensor: it is used to measure the pressure difference between two different positions or systems. It is widely used in flow measurement, liquid level measurement and other situations. For example, the fluid flow is calculated by measuring the pressure difference between two points in the pipeline.

Absolute pressure sensor: measure the pressure relative to the absolute vacuum, which is not affected by the change of atmospheric pressure. It is commonly used in aerospace, meteorological monitoring and other fields, such as measuring the absolute atmospheric pressure corresponding to the height of the aircraft.

Classified by output signal type:

Analog signal pressure sensor: the output is a continuous analog signal, such as voltage and current signals. Common 4-20mA current output or 0-5V voltage output can be directly connected with most analog input modules or instruments.

Digital signal pressure sensor: the output is digital signal, such as I2C, SPI, RS485 interface, etc., with strong anti-interference capability, long transmission distance, easy integration with digital system, etc., which can realize more accurate data transmission and remote control.