This circuit was found in a 1945 publication. The circuit was stated to be part of a walk talkie. Note that, as it is a portable assembly, it was powered by batteries. The jack was for microphone insertion.
This circuit was found in an American documentation from the 70s, but it can be implemented with a...
This integrated contains a Class B circuit originally developed to provide 6 W in a car radio...
This differential amplifier, found in a 1964 Electronic Design, has a gain of 30. The setting can be...