This circuit was found in a 1980s documentation. Similar configurations appear in the section, but from different sources. The circuit makes use of components of the time.
The LS4558 integrated circuit is a double 741. The filter response curve is given next to the...
This motor control using transistors was found in a recent English publication. The circuit is for...
This circuit from a 90s Popular Electronics, decodes the old analog TV signal. It works with a...