This circuit was found in a 1967 US documentation. It shows how to build a gain control by digital signals. The circuit can be used as a shield. FET can be a modern equivalent.
Found in the July 1968 Supertena Bulletin of a Popular Electronics, this receiver makes use of the...
This switching source was obtained in a 1976 National Semiconductor manual. For the indicated...
This configuration appears several times on this site. The circuit can generate a 100 kHz or other...