This commercial earphone receiver was manufactured in the 1960s in Japan. It was powered by a 9 V battery and the transistors were made of germanium.
This General Electric circuit, in a documentation from the 1960s, allows the use of high...
This signal injector and tracer (follower) was found in an old American documentation. The...
This is the traditional configuration of an unregulated bridge rectified power source. The circuit...