Working of a DC buzzer

[arunbhaskar]

I tried to find out how a DC buzzer is connected in a circuit to make sound. I couldn't find much about it. All I could figure out is there are two connections, one connected to supply and other connected to 555 timer output.
I wanted to know the principle of working and how to excite the buzzer terminals for its proper working. Thank you.

 

[pranam77]

Buzzers are those devices which produce a sound between 1 and 8Khz with vibrating a piezo element or a small speaker with a metal diaphragm.

Basically there are two types of Buzzers. One with a bult in oscillator to produce an audible sound, other without the Oscillator. The same is powered by an external source. Which one you are refering to?

 

[arunbhaskar]

Please explain to me both types of buzzers. Thanks.

 

[pranam77]

1. Piezo Buzzer mainly consists of a multi-vibrator circuit, piezoelectric buzzer films, and the resonance box, shell etc. Multivibrator constits of transistors or integrated circuits. When switched on, after (1.5 ~ 15V DC working voltage), multi-harmonic oscillator start-up, output 1.5 ~ 2.5kHZ of audio signals, which results in audible sound.
Piezoelectric Buzzer contains zirconate titanate films from lead or lead magnesium niobate piezoelectric ceramic materials. On both sides of the ceramic coating on the silver electrode by polarization and aging treatment, and then with the brass plates or stainless steel sheets stick together.

Electromagnetic Buzzer works from the oscillator, the electromagnetic coil, magnet, diaphragm and shell so on. After power on, the audio oscillator signal current through the electromagnetic coil, so that the electromagnetic coil produces a magnetic field. Diaphragm in the electromagnetic coil and magnet interaction, periodically vibrating voice and thus the audible note.

There are too Electromagnetic Buzzers which works without any oscillator. These work by the frequency produced by the make and break contacts to the coil in relation to the moving diaphragm.

Cheers

 

[arunbhaskar]

Thanks. I've understood. Can you post some of the simple buzzer circuits so that I can improve my understanding.

 

[pranam77]

Sorry...i dont have any...google is your best friend...Cheers

 

[Audioguru]

I have an extremely simple oscillator circuit that is in most piezo beepers: