Piezo buzzer is the handy sound generator used in electronic circuits to give audio indication .It is widely used as alarm generator in electronic devices. It is available in various types and size to suit the requirements. A Piezo buzzer has a Piezo disc and an oscillator inside. When the buzzer is powered, the oscillator generates a frequency around 2-4 kHz and the Piezo element vibrates accordingly to produce the sound. An ordinary Piezo buzzer works between 3 – 12 volts DC.