A transducer can classify the sound generation principle as magnetic, external drive piezo, self-drive piezo, or mechanical. According to the sound generation principle and require AC voltage (Vpp / VAC) as the driver since there is no built-in driver circuit (passive). The transducer is without an oscillation source. Therefore, it provides customers greater design flexibility and small product size. Customers can control the output frequencies, multi-frequency, or voice according to their needs. The minimum size is 3.2mm, and different types of pin, wire, SMT, and solder pad terminals are available for different assembly needs.