Pressure sensor is the most common industrial practice, a sensor, and we usually use pressure sensor is mainly manufactured using piezoelectric effect, and this sensor is also known as piezoelectric sensor.
We know that the crystals are anisotropic, amorphous is isotropic. Some crystal medium, when a certain direction by mechanical force deformation occurs, is the polarization effect; When a mechanical force, after removed and will be returned to the electrically neutral state, that is, when the pressure, some crystal may produce electric effect, this is the so-called polarization effect. Scientists is according to the effect of pressure sensor is developed.
Piezoelectric sensor in the main use of piezoelectric materials include quartz, sodium potassium tartrate and ammonium dihydrogen phosphate. Quartz (silica) is a kind of natural crystal, piezoelectric effect is found in the crystal, within certain limits of temperature, the piezoelectric properties have always existed, but after the temperature exceeds the scope, the piezoelectric properties disappear completely (the high temperature is the so-called "Curie point"). Due to the changes as the change of stress field of tiny (also said piezoelectric coefficient is low), so is gradually replaced by other piezoelectric crystal quartz. And sodium potassium tartrate has great sensitivity and piezoelectric piezoelectric coefficient, but it can only be at room temperature and low humidity environment to the application. Ammonium dihydrogen phosphate are synthetic crystals, can bear high temperature and high humidity, so
Has been widely used.
In piezoelectric effect are also applied in polycrystal now, such as the piezoelectric ceramic, including barium titanate, PZT piezoelectric ceramics, magnesium niobate piezoelectric ceramic, niobium acid lead piezoelectric ceramics, and so on.
Piezoelectric effect is the main working principle of piezoelectric sensors, piezoelectric sensors cannot be used for static measurements, because the charge, after external force only has infinite input impedance in the loop when saved. The actual situation is not so, so this determines the piezoelectric sensors can only measure the dynamic stress.
Piezoelectric sensor is mainly used in measuring acceleration, pressure and force. Piezoelectric acceleration sensor is a kind of common accelerometer. It has simple structure, small volume, light weight, long life and other excellent characteristics. Piezoelectric acceleration sensor in the planes, cars, ships, Bridges and buildings vibration and impact measurement has been widely used, especially in the field of aviation and aerospace has its special status. Piezoelectric sensors can also be used to measure engine internal combustion pressure and vacuum measurement. Can also be used in military industry, for example, use it to measure gun bullet firing moment in the chamber of the change of the bore pressure and the muzzle shock wave pressure. It can be used to measure pressure already, also can be used to measure small pressure.
Piezoelectric sensors are widely used in biomedical measurement, such as ventricular catheter microphone is made of piezoelectric sensor, because of the dynamic pressure measurement is so widespread, so the application of piezoelectric sensors is very wide.
Besides piezoelectric sensors, and produced on the piezoresistive effect of piezoresistive sensors, strain sensor makes use of the effects of strain, etc., these different pressure sensor with different effect and different materials, can play to their unique purpose in different occasions.
