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