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 circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...