What is the sound of the alarm?
2. Electromagnetic buzzer The electromagnetic buzzer consists of an oscillator, an electromagnetic coil, a magnet, a diaphragm and a housing. When the power is turned on, the audio signal generated by the oscillator is passed through the electromagnetic coil to cause the electromagnetic coil to generate a magnetic field. Vibration diaphragm in the electromagnetic coil and the interaction of the magnet, the periodic vibration of the sound.
1. Piezoelectric buzzer Piezo buzzer mainly composed of multivibrator, piezoelectric buzzer, impedance matching and resonance box, shell and so on. Some piezoelectric buzzer shell is also equipped with light-emitting diodes. Multivibrator consists of a transistor or an integrated circuit. When the power is turned on (1.5 ~ 15V DC operating voltage), the multivibrator starts, output 1.5 ~ 2.5kHZ audio signal, the impedance matching device to promote the piezoelectric buzzer sound. The piezoelectric buzzer is made of lead zirconate titanate or lead niobate lead piezoelectric ceramic material. Silver electrodes are plated on both sides of the ceramic sheet, polished and aged, and then with the brass or stainless steel sheet together.
Are generally buzzers in the alarm, of course, is not a musical instrument
