Positive piezoelectric effect
The positive piezoelectric effect means that when the crystal is subjected to an external force in a certain direction, electric polarization is generated 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 ; When the direction of the external force changes, the polarity of the charge also changes; the amount of charge generated by the crystal is directly proportional to the magnitude of the external force. Most piezoelectric sensors are made using the positive piezoelectric effect.