Wailing Alarm Siren
This circuit provides a warbling sound to any alarm circuit. IC2 is
wired as a low frequency astable that has a cycling period of about 6 seconds. The slowly
varying ramp waveform on C1 is fed to pnp emitter follower Q1, and is then used to
frequency modulate alarm generator IC1 via R6. IC1 has a natural center frequency of about
800Hz. Circuit action is such that the alarm output signal starts at a low frequency,
rises for 3 seconds to a high frequency, then falls over 3 seconds to a low frequency
again, and so on ad infinitum.
Presiona el botón para volver al menú
