A piezoelectric speaker, also known as piezo, buzzer, and crystal loudspeaker, is a device that uses a piezoelectric effect to produce a sound. The sound is generated by applying a voltage to a piezoelectric material that creates a mechanical motion. Resonators and diaphragms often transform the mechanical motion into an audible sound. It’s worth mentioning that piezoelectric speakers are easy to control and they work within a certain range that goes from 1Hz to 100kHz.
When the vibration area of the piezoelectric speaker spreads a great number of piezoelectric sheets, it creates a compact piezoelectric speaker. When the pattern of the first and the second electrodes is the same and generate within the vibration area of the piezoelectric speaker, a stereo speaker is created. When one of the patterns is different, a 2-way or 3-way speaker is formed.
The first and second electrodes almost always include a thin layer made of indium tin oxide, indium zinc oxide, and zinc oxide, or a layer made of a polythiophene conductive polymer. It’s worth mentioning that the first and second electrodes are created in such a way that its layer involves zinc oxide as well as polythiophene conductive polymer which tends to overlap. This configuration also applies to the speaker equipment which includes both a frame and a piezoelectric loudspeaker. These devices are placed on the front surface of the frame.
Piezoelectric speakers can be found in many devices such as digital quartz watches, computer speakers and portable radios. Piezoelectric speakers are responsible for the ultrasounds produced in sonar systems. Piezoelectric speakers are extremely resistant to overloads. On the other hand, some amps might oscillate when driving capacitive loads, creating distortion or damage to the amplifier. The frequency response of piezoelectric speakers is quite low, especially when referring to mid-range and bass. These devices are commonly used in applications where high sound pitch and volume are essential.