1. Principle and application of capacitive pressure sensor
The capacitive transmitter has a variable capacitance sensing component. The sensor is a completely closed component. The process pressure, differential pressure is transmitted to the sensing diaphragm through the isolating diaphragm and filling liquid silicone oil to cause displacement. The capacitance difference between the sensing diaphragm and the two capacitor plates is converted into an electrical signal output by a two-wire system of (4-20) mA by electronic components.
2.Principle and application of ceramic pressure sensor
The corrosion-resistant ceramic pressure sensor has no liquid transmission. The pressure acts directly on the front surface of the ceramic diaphragm, causing the diaphragm to deform slightly. The thick film resistor is printed on the back of the ceramic diaphragm and connected to form a Wheatstone bridge (closed). bridge), due to the piezoresistive effect of the varistor, the bridge generates a highly linear voltage signal proportional to the pressure and also proportional to the excitation voltage. The standard signal is calibrated to 2.0/3.0/3.3 according to the different pressure ranges mV/V, etc., compatible with strain gauge sensors. Through laser calibration, the sensor has high temperature stability and time stability, the sensor has its own temperature compensation 0 ~ 70 ℃, and can be in direct contact with most media.
3.Principle and application of diffused silicon pressure sensor
Working principle The pressure of the measured medium acts directly on the diaphragm of the sensor (stainless steel or ceramic), causing the diaphragm to produce a micro-displacement proportional to the pressure of the medium, changing the resistance value of the sensor, and detecting this change with an electronic circuit. , and convert and output a standard measurement signal corresponding to this pressure. Using the working principle of strain resistance, silicon-sapphire is used as the semiconductor sensitive element, which has good measurement characteristics.
