This high quality circuit with complementary symmetry was found in an Electronics World of 1966. It can be made with modern transistors like the BD or TIP series.
This water level control circuit was found in a 1980s documentation. The circuit uses a capacity...
This circuit was obtained in an English publication from 1980 but can still be assembled with...
This circuit is from an American cookbook from 1977. The circuit generates a voltage of...