Kailitech piezo ceramic products include piezo elements, piezo buzzers, piezo ultrasonic transducers and piezo speakers, hereby below we mainly introduce Kailitech piezo elements, and the 3 types of piezo buzzers: passive piezo buzzer, active piezo buzzer and self drive piezo buzzer.
＊L1, R1, C1, are respectively the inductance, resistance and capacitance at resonance, and C0 is the static capacitance.
Therefore, the piezo element is actually a LC oscillator circuit. When an alternating signal is input, it will oscillate and deform to make a sound. When the input frequency reaches the same phase as the signal voltage and current, it will resonate. This frequency is called the resonant frequency ( Fr).
＊K: constant figure
＊t: total thickness of piezo element
＊D: diameter of piezo element
＊C: supporting mode coefficient, as below:
﹡C= 0.412 for
Node Supporting Mode：
﹡C= 0.233 for
Edge Supporting Mode：
﹡C= 0.172 for
Centre Supporting Mode：
To achieve higher sound pressure and sensitivity, piezoelectric materials must be of good performance. When applying constant voltage( V), the micro-displacement (deformation) of the piezo element is:
＊Kp： The flat electromechanical coupling coefficient of Piezoelectric material
＊D31: Piezoelectric constant
Only materials with higher D31, Kp, and E33T can produce large micro- displacement and generate high sound pressure. Therefore, good quality piezoelectric material is the key to the performance of the piezo element.
Yet, the piezo element alone is difficult to match the acoustic impedance of the air and to get high sound pressure level. It must be combined with an acoustic resonator to amplify the sound, increase the sound pressure output, and improve the frequency characteristics.
The acoustic resonator is composed of case (resonance cavity), sound cavity (divided into front cavity and rear cavity), sound emitting hole and with or without circuit board.
The resonance frequency of the acoustic resonator is also called the inherent frequency ( fo) of the acoustic resonator:
﹡d：diameter of the sound emitting hole
﹡t ：the thickness of the sound emitting hole
﹡D：edge support diameter ≈ piezo element diameter
﹡H：depth of front acoustic cavity
Therefore, when designing buzzer, how to perfectly match the acoustic resonator and piezo element becomes the key to the development of high-quality buzzers, which involves comprehensive applications in many fields such as chemistry, electronics, structure, and acoustics.
Kailitech has established an independent R & D centre, integrating production, education and research. Kailitech lab has full range of R&D equipments, such as wide-width sweep frequency tester, material granularity analyzer, d33 tester, spectrum analyzer, metallographic microscope, etc., as well as reliability verification test equipments which guarantees reliabilities for the new products testing, with great advantages to design and manufacture customerized models.