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.

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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.

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