Piezoelectric Speaker

A piezoelectric speaker is also known as piezo, buzzer, and crystal loudspeaker. It is a device that uses a piezoelectric effect to produce a sound. By applying a voltage to a piezoelectric material that creates a mechanical motion, the sound emerges. Resonators and diaphragms often transform the mechanical motion into an audible sound. In addition, piezoelectric speakers are easy to control and they work within a certain range: from 1Hz to 100kHz.

An Introductory Comparison

Simply put, when the vibration area of the piezoelectric speaker spreads a great number of piezoelectric sheets, it creates a compact piezoelectric speaker. In contrast, a stereo speaker comes from the pattern of the first and the second electrodes being the same, generated within the vibration area of the piezoelectric speaker. As a third option, when one of the patterns is different, a two-way or three-way speaker forms. 

Piezoelectric Speaker: Components

The first and second electrodes almost always include a thin layer made of indium tin oxide, indium zinc oxide, and zinc oxide. If not, they usually contain a layer made of a polythiophene conductive polymer. The design of these first and second electrodes is such that its layer involves zinc oxide as well as polythiophene conductive polymer, which tends to overlap. This configuration also applies to the speaker equipment that includes both a frame and a piezoelectric loudspeaker. You should place these devices on the front surface of the frame.

Some Examples

You can find piezoelectric speakers in many devices, such as digital quartz watches, computer speakers, and portable radios. On the one hand, these devices are responsible for the ultrasounds in sonar systems. Additionally, these speakers are extremely resistant to overloads. On the other, some amps might oscillate when driving capacitive loads. In turn, this creates distortion or damage to said amplifier. The frequency response of piezoelectric speakers is quite low, especially when referring to mid-range and bass. For these reasons, users commonly employ piezoelectric speakers in applications where high sound pitch and volume are essential.