Active Buzzer Electromagnetic 3-12V Alarm Raspberry PIC Electromagnetic

 

 

 

 

Buzzer

Buzzer is a pronunciation device that can transmit audio signals into sound signals. It is widely used in household appliances, electronic toys and game consoles. The buzzer is mainly used for prompt or alarm. According to the different appearance and purpose, it can emit different sounds such as music, siren, alarm and ringing tone.

The buzzer used in the washing machine sends out a buzzer to remind the user of the operation process.

In gas appliances, the buzzer is used to send out an alarm sound to warn the user that the gas appliance is burning. As a doorbell application, the buzzer mostly emits a "ding-dong" sound or music sound to prompt guests to visit. The buzzer installed in the family warning area sends out multiple alarm sounds. In factories and applications, buzzers often emit electric ringing tones. According to different types of buzzers, their working power supply is also different. Some are connected to DC, such as the electric horn used in cars, some are connected to AC, and some need to be connected to a specific electronic circuit.

 

Composition of buzzer

The buzzer is made of lead zirconate titanate or lead magnesium niobate piezoelectric ceramic material. The silver electrode is plated on both sides of the ceramic sheet, and then adhered to the brass sheet or stainless steel sheet after polarization and aging treatment.

 

Principle of buzzer

The buzzer works based on the principle of piezoelectric effect. When alternating voltage is applied to it, it will produce mechanical vibration; On the contrary, when mechanical force is applied to it, it will also generate voltage signal. Therefore, piezoelectric ceramic buzzer can be used as a vibration sensor. The voltage signal generated by the piezoelectric ceramic buzzer is very weak when it is subjected to mechanical force. Generally, the voltage amplifier should be connected when it is used as a vibration sensor.

Scope of application

Computer, printer, repeater, alarm, electronic toy, automobile electronic equipment, telephone, timer, etc.

 

Matters needing attention:

The buzzer cannot be used as a mineral radio, because there is an oscillation circuit inside the buzzer. When the power is turned on, it will drive a miniature horn inside to emit a beep. The buzzer is not a simple trumpet. In addition, there are two kinds of buzzers. One is internal oscillator; One is to connect an oscillator, that is, an ordinary miniature horn. For the type without oscillator, it cannot be used, because its resistance is generally about 32 ohms, and there are 8 ohms or 16 ohms, which are low impedance, so it cannot be used. If there is no high resistance earphone, you can also use a power transformer of 6V or 12V, and the power is about 3 to 5W, because the primary wire diameter of the transformer is very thin, the number of turns is also large, and the impedance is also large. The purpose is to make the load obtain good impedance matching and maximum power. The use method is as follows: connect the transformer's primary (the winding resistance connected to 220V) to the place where the high resistance earphone was originally connected, and then connect the secondary to your ordinary earphone.