Example of driver circuit design for a buzzer

Buzzer, also known as buzzer, English BUZZER, is a miniaturized electroacoustic device, which is divided into two categories: piezoelectric and electromagnetic according to the working principle.
The piezoelectric buzzer is made of piezoelectric ceramic plate, when the audio signal is applied to the piezoelectric ceramic plate, under the action of the inverse piezoelectric effect, the ceramic plate will mechanically vibrate with the frequency of the audio signal, thereby emitting an acoustic sound.
Resistor R1 is the bias resistor of BG1 tube, and its resistance value determines the circuit operating current on the one hand, and also has a great influence on the level of pronunciation tone. The R1 resistance increases, the HTD voice is low, the R1 resistance decreases, and the HTD pronunciation becomes higher. Resistor R2 is the collector load resistance of transistor BG2. Capacitor C1 is the negative feedback capacitor of BG1 tube, which can change the pronunciation and timbre of HTD by changing its capacity.
The inside of the electromagnetic buzzer is composed of magnets, coils and vibrating diaphragms, etc., when the audio current flows through the coil, the coil generates a magnetic field, and the diaphragm is attracted and released with the same audio signal, generating mechanical vibration, and making sound under the action of the resonance cavity.