This circuit was originally intended for reading movie soundtracks. The circuit is from 1967 and was found in an English publication. The sensor is semiconductor type.
This circuit appears in other articles in this section, but it is very interesting. It is a...
This alternating flasher was found in a 1980s documentation. The transistors may be equivalent such...
This simple CMOS circuit generates two-frequency signals for use as a signal injector. The circuit...