How to choose a buzzer
There are many types and specifications of buzzers, and you need to know several parameters (voltage, current, driving method, size, connection/fixing method), and of course, more importantly, the sound you want to get (sound pressure, frequency).
Working voltage: Electromagnetic buzzer, from 1.5 to 24V, piezoelectric from 3V to 220V are feasible, but generally piezoelectric is recommended to have a voltage of more than 9V to obtain a louder sound.
Current consumption: The electromagnetic type varies from tens to hundreds of milliamperes depending on the voltage. The piezoelectric type saves more power. A few milliamps can operate normally. consumes about three times as much current,
Driving mode: Both types of buzzers are self-excited, as long as they are connected to direct current (DC), they can sound, because the driving circuit has been built in the buzzer, because of the different action principles, the electromagnetic buzzer The device should be driven by a 1/2 square wave, and the piezoelectric device should be driven by a square wave to have better sound output.
Size: The size of the buzzer will affect the volume and frequency. The minimum size of the electromagnetic type is from 7mm to the maximum of 25mm, and the piezoelectric type is from 12mm to 50mm or more.
Connection method: Commonly used pins (DIP), soldering wires (Wire), SMD (SMD), piezoelectric large ones and locking screws.
Sound pressure: Buzzers are often tested at a distance of 10cm. If the distance is doubled, it will attenuate about 6dB. On the contrary, if the distance is doubled, it will increase by 6dB. The electromagnetic buzzer can reach the level of about 85dB / 10cm. , Piezoelectric can be made very loud, most of the common alarms are made of piezoelectric buzzers.
