The continuous development of science and technology has greatly enriched the types of pressure measurement products. At present, the sensitive principles of pressure sensors include not only capacitive, piezoresistive, metal strain, Hall, vibrating cylinder, etc. but still capacitive, Piezoresistive
Metal strain sensors are the most common. 是一种历史较长的压力传感器，但由于它存在迟滞、蠕变及温度性能差等缺点，其应用场合受到了很大的限制。 Metal strain type pressure transmitter is a kind of pressure sensor with a long history, but because of its shortcomings such as hysteresis, creep and poor temperature performance, its application is greatly limited. Piezoresistive sensors
It is a new type of sensor manufactured by using the semiconductor piezoresistive effect. It has the characteristics of convenient manufacturing and low cost, but because the semiconductor material is extremely sensitive to temperature, its performance is greatly affected by temperature, and the consistency of the product is poor.
是应用最广泛的一种压力变送器，其原理十分简单。 Capacitive pressure transmitter is the most widely used type of pressure transmitter, and its principle is very simple. The capacitance of an infinite parallel plate capacitor can be expressed as: C = ε s / d (ε is the dielectric constant of the medium between the parallel plates, d is the distance between the plates,
s is the coverage area of the electrode plate) Change one of the parameters to change the capacitance. Due to the simple structure, almost all capacitive pressure transmitters use the method of changing the gap to obtain variable capacitance. 的初始电容值较小， The initial capacitance value of the capacitive pressure transmitter is small,
It is generally several tens of picofarads. It is extremely susceptible to the influence of the wire capacitance and the distributed capacitance of the circuit. Therefore, advanced electronic circuits must be used to detect small changes in capacitance. It can be said that a good capacitive sensor should be a variable capacitor design and signal processing circuit
Perfect combination. .