The idea of this circuit is that when the device in SO1 is turned on, the device connected to SO2 automatically receives power. The circuit is from Radio Electronics from January 1985.
The automatic modulated siren circuit shown in the figure really produces an interesting sound...
This circuit was found in the August 1973 issue of Radio Electronics magazine. The Darlington...
This circuit has three settings, central sound frequency, modulation speed and modulation depth. The...