We found this circuit in the September 1971 Radio Electronics magazine. The SCR can be any of the 106 series and the buzzer can be replaced by a relay according to the supply voltage.
This oscillator produces a rectangular signal in the range of 100 Hz to 1 kHz, but by changing the...
This circuit was originally designed for the alarm of the CB17984E, but it also serves for any...
We found this version of the siren that makes the American police siren sound in a 1980...