An electronic siren including yelp and wail oscillators, means for mixing the signals from the yelp and wail oscillators, and an amplifier output circuit for broadcasting the mixed yelp and wail signals. The wail oscillator is adapted to operate automatically or may be operated manually by means of a push button or from remote switching means. The wail oscillator may also be switched to operate with a siren sound or a horn sound having a variable pitch.A CD4093 chip and a few components make up a siren oscillator, which drives power MOSFET Tl. 4 speaker is driven directly from this device.The siren is enabled by a logic high applied to the ENABLE input.
In operation, the electronic siren will provide a microphone or radio output, a manually selected automatic siren or horn sound output from the wail oscillator, the output of both the wail and yelp oscillators simultaneously, or the output of the yelp oscillator.