Described in an article in the March 1979 issue of Radio Electronics magazine, this generator was used in an audio test station. The frequencies are given by the capacitors.
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...