Posted on Jul 18, 2012

The simple circuit transforms the steady beep of an audible-signal device, such as a Mallory sonalert, into a distinctive warble or chirp. The value of R, C2 determines just what tone color you`ll get. With 1k the 1-I`F value shown, the circuit produces a warble similar to the ring tone of an inexpensive phone. A R, 10-I`F value produces a chirp similar to a truck`s 2ok back-up alarm.

Click here to download the full size of the above Circuit.

One elaboration of this circuit would be to use the second section of a 555 timer to drive a piezoelectric transducer instead of a sonalert; that modification would vary the tone"s pitch, as well as the chirp rate.

Leave Comment

characters left:

New Circuits



Popular Circuits

RC Charger
AC Millivoltmeter Adapter
Dark and Light Activated Relay
am to fm converter
audio preamplifier
LC Meter Circuit Coil Capacitor Meter
10GHz White Box Conversion Notes
Opamp VHF FM Transmitter
12V-220V Modified Sine-wave Inverter Circuit
Ratio discriminator circuit