The basic principle of piezoelectric ceramic buzzer and the application of piezoelectric buzzer

Publish Time: 2019-08-13     Origin: Site

Piezoelectric ceramic buzzer is a device used in piezoelectric ceramic sheets. It is more common to form titanium and piezoelectric ceramic sheets (pzt) sintered with zirconium and lead oxides. Since the human ear is most sensitive to the audio signal of 3khz, the resonant frequency of the piezo element film is usually designed during production. Around 3khz. In order to improve the low frequency response, a double piezo diaphragm structure is generally employed.


In an ionic crystal, positive and negative ions are regularly arranged in the staggered manner to form a crystal lattice. This creates an intrinsic piezoelectric ceramics, a polarized charge appears on the surface of the piezo film element, and because the piezoelectric crystal is exposed to the air, over time, the charge is neutralized by the alien ions in the air that fall onto the crystal face. Therefore, both the polarization surface charge and the electric moment do not appear. However, when the crystal is mechanically deformed, the crystal lattice changes. Thus, the electric moment changes and the surface polarization charge value changes. Thus, the positive or negative charge on the surface has a measurable increment (increase or decrease), which is the amount of electricity produced by the piezoelectric effect.


Piezoelectric buzzer In general, a human's audio range is between approximately 20 Hz and 20 kHz. The most audible audio is 2kHz to 4kHz. Therefore, most piezoelectric sound elements are used in this audio range. At the same time, the piezo diaphragm piezoelectric film ‘s resonance frequency (f0) is generally selected to be in the same range. The resonant frequency depends on the method used to support the piezoelectric diaphragm.


Normally, a piezoelectric diaphragm is installed in the resonance chamber to generate a high sound pressure. Using the formula (Hermholtz formula), the resonant frequency (fcav) of the resonance chamber can be calculated. Since the piezo disc benders and the resonance chamber have appropriate resonance frequencies, respectively (f0) and (fcav), it is possible to increase the sound pressure at a specific frequency and obtain a specific bandwidth by controlling the positions of both.


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