This DC motor control uses a power operational amplifier. We found it in December 1984 in the Radio Electronics magazine. The amplifier must be mounted on a heat sink and the maximum current is 1 A.
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...