When the direction of external force changes, the polarity of the charge also changes the amount of charge generated by the crystal is proportional to the magnitude of the external force. The positive piezoelectric effect means that when the crystal is subjected to an external force in a fixed direction, electric polarization occurs inside the crystal, and charges of opposite signs are generated on two surfaces at the same time. When the external force is removed, the crystal returns to an uncharged state. The piezoelectric effect can be divided into the positive piezoelectric effect and the inverse piezoelectric effect. The disadvantage is that some piezoelectric materials need moisture-proof measures, and the output DC response is poor. High input impedance circuits or charge amplifiers are needed to overcome this defect. Its advantages are wide bandwidth, high sensitivity, high signal-to-noise ratio, simple structure, reliable work, and lightweight. Piezoelectric sensors are used to measure force and non-electrical physical quantities that can be transformed into electricity. Then it becomes a power output proportional to the external force received. The charge is amplified by the charge amplifier and the measuring circuit and transformed into impedance. The piezoelectric material generates an electric charge on the surface after being forced. Its sensitive components are made of piezoelectric materials. It is a self-generating and electromechanical conversion sensor. Used for processing technology monitoringĪ piezoelectric sensor is a sensor based on the piezoelectric effect. Used for structural static deformation controlĤ.

Piezo vibration sensor