This step of good gain was obtained in an American publication of the 1980s. The circuit can be powered by voltages from 3 to 9 V and the FET can be of almost any type.
This circuit obtained in a 1989 documentation can be useful for photographers in determining...
The circuit shown is from an old European publication. In it we have the way to activate a relay...
Toshiba's TCH8H611FNG integrated circuit makes it possible to control stepper motors up to 0.8 A...