The circuit presented here demonstrates how to generate Audible Frequency from an AVR Microcontroller. The output of Microcontroller is always digital so to generate audible sound at the outset first it needs to be converted into Analog. A DAC (Digital to Analog Converter) is used for this purpose. Microcontroller generates sine wave of Audible Frequency using DAC. This sine wave is further given to Audio Amplifier that drives speaker. Microcontroller generates sine wave of fix frequency continuously. So we can hear an audible tone of fix frequency