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555 Audio Tone / Siren Circuit

Created on: 15 May 2013

This circuit can easily be built on an electronic breadboard and uses a 555 timer IC to produce an audible tone of about 750Hz on a loudspeaker.

The circuit can be used as a warning siren or in place of a buzzer.

Circuit Diagram

Although the circuit diagram shows the circuit operating from 9V, it should operate from about 5V to about 12V.

An 8 ohm loudspeaker driven by the 555 IC produces the audible square-wave tone.

555 IC audio tone circuit

Circuit Operation

This video shows the circuit operating and the frequency produced by the 555 being measured.

Can't see the video? View on YouTube →