The structure principle of buzzer(a) the introduction of a buzzer: 1. The role of the buzzer buzzer is an integration of electron acoustic structure, USES the dc power supply, is widely used in computers, printers, photocopiers, alarm, electronic toys, automotive electronic equipment, telephone, timer and other electronic products for voice devices.2. Buzzer classification: mainly divided into piezoelectric buzzer and magnetic buzzer two types.3. The buzzer circuit graphic symbol: buzzer in circuit with the letter "H" or "HA" (old standard with "FM", "LB", "JD", etc.).Buzzer schematic(2) the structure principle of buzzer1. The piezoelectric buzzer: piezoelectric buzzer buzzer is mainly by multivibrator, piezoelectric, impedance matching unit and sound box, shell, etc. Some of the piezoelectric buzzer also equipped with light-emitting diodes (leds).Multivibrator composed of transistors or integrated circuits. When after turning on the power supply (1.5 V to 15 V dc voltage), multivibrator vibration, 1.5 2.5 kHZ audio signal output, impedance matcher driving piezoelectric buzzer sound.By lead zirconate titanate piezoelectric buzzer or niobium magnesium acid lead piezoelectric ceramic materials. On both sides of the ceramic chip plating silver electrodes, after polarization and aging treatment, with brass or stainless steel pieces together again.2. Magnetic buzzer: magnetic buzzer by the oscillator, the electromagnetic coil, magnets, vibration membrane and shell, etc.After turning on the power supply, audio signals generated by oscillator by electromagnetic coil current, make the electromagnetic coil produces magnetic field. Diaphragm vibration under the interaction of electromagnetic coil and magnet, periodic vibration.(3) the buzzer
