Using the 723 integrated circuit, this circuit was found in an article on power supplies in the August 1971 Radio Electronics magazine. The transistor may be the BD136 on a heatsink.
The circuit shown in figure 1 serves to control a servo motor with a current of up to 200 mA. The...
The L3 coil is what basically determines the resonant frequency, around 1 MHz, in this oscillator found...
This circuit was found in a 1973 Radio Elettronica magazine. The Italian magazine no longer...