The working principle of piezoelectric ceramic element

In an piezo ceramic element crystal, the positive and negative ions are regularly arranged alternately to form a crystal lattice. This creates an intrinsic electric moment, a polarized charge appears on the surface of the crystal, and because the crystal is exposed to the air, after a period of time, the charge is neutralized by the alien ions in the air that falls on the piezo crystal , thus Both the polarization surface charge and the electric moment do not appear, but when the piezo crystal undergoes mechanical deformation, the crystal lattice changes. Thus, the electric moment changes, and the surface polarization charge value also changes. Thus, there is a measurable increase (increase or decrease) in the positive or negative charge on the surface. This increment is the piezoelectric effect.

It mainly describes the principle, polarization and vibration mode of piezoelectric ceramic buzzer, which gives you a comprehensive understanding of the structure and principle of piezoelectric ceramic buzzer. The principle of piezoelectric ceramic chip buzzer, some materials under the action of mechanical stress, causing the relative displacement of the internal positive and negative charge centers to be polarized, resulting in the phenomenon of oppositely bound charges on the two ends of the material, called piezoelectric effect. Piezoceramic having such properties is called a piezoelectric ceramic, and its surface charge density is proportional to the mechanical stress it receives. Conversely, when such materials are subjected to an external electric field, the internal positive and negative charge centers are displaced, which may cause mechanical deformation of the material. The magnitude of the deformation is proportional to the electric field strength in the process of making the buzzer into the piezoelectric ceramic material. It must be polarized, and the piezoelectric ceramic material must be polarized to have piezoelectric properties; polarization is to orient the ferroelectric domains in the piezoelectric ceramic direction of the electric field under the action of a direct current electric field. The radial vibration mode of the piezoelectric ceramic piece buzzer, the radial vibration mode of the piezoelectric ceramic disk is a commonly used vibration mode, and the stretching vibration along the radial direction of the wafer is called the radial vibration mode.

There are two types of piezo diaphragm piezoelectric buzzer driving methods, namely external driving method and self-driving method. As shown in Figure 5.

There are four types of circuits for piezo diaphragm buzzer using external drive method, which are a circuit driven by an unstable multi-frequency oscillator output signal. Oscillation or stop is generated by the on/off operation of the input signal. c. A circuit driven by a CMOS LSI output signal. d. A piezoelectric diaphragm connected by a telephone electromechanical ring integrated circuit..