Piezoresistive pressure sensor is composed of piezoresistive effect of monocrystalline silicon.
Piezoelectric pressure sensors are mostly made of positive piezoelectric effect.
2. Different emphases
When the crystal of piezoelectric pressure sensor is acted by an external force in a fixed direction, polarization occurs inside, and the two surfaces simultaneously produce charges with opposite signs; When the external force is removed, the crystal returns to the uncharged state; When the direction of external force changes, the polarity of charge also changes; The amount of charge generated by the force on the crystal is proportional to the magnitude of the external force.
Piezoresistive pressure sensor uses monocrystalline silicon as elastic element. On the monocrystalline silicon diaphragm, a group of equivalent resistors are diffused in the specific direction of monocrystalline silicon by using integrated circuit technology, and the resistors are connected into a bridge. A monocrystalline silicon wafer is placed in the sensor cavity. When the pressure changes, the single crystal silicon produces strain, so that the strain resistance directly diffused on it changes in direct proportion to the measured pressure, and then the corresponding voltage output signal is obtained through the bridge circuit.
3. Different structures
Piezoelectric pressure sensor A pressure sensor based on piezoelectric effect. There are many kinds and models of it, which can be divided into diaphragm type and piston type according to the form and force mechanism of elastic sensitive elements. Diaphragm type is mainly composed of body, diaphragm and piezoelectric element.
Piezoresistive sensor adopts integration technology to integrate the resistance strip on the monocrystalline silicon diaphragm to make a silicon piezoresistive chip, and the periphery of the chip is fixedly packaged in the shell, and the electrode leads are led out.
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