The gates of a 4093 can be used form a two-tone siren as shown in the configuration of Figure. The tone is given by C2/R2 and the modulation by C1/R1. R1 and R2 can be experimented with in a large range of values. If you would like a frequency adjustment for the oscillators, use trimmer potentiometers to replace the resistors. A buffer is recommended if the other gates of the ID will be not used in the application. The circuit can drive a small piezoelectric transducer. For highpower loads, such as loudspeakers, use a drive stage with a transistor.
