This voice scrambler and descrambler circuit was found in a Radio Electronics from July 1963. Transformers are common types at the time with impedances according to telephones and line.
This circuit has an interesting application. If a device with the selector switch in the 110 V...
This simple radio circuit was obtained in a Japanese publication in 1967. The circuit uses...
This circuit was found in a Popular Electronics from the 90's. The components used are common and...