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 circuit consists of a booster for the medium wave band. We found it in an English publication from...
This circuit converts signals from the 350 kHz to 500 kHz longwave (VLF) band to the 4.35 to 4.6...
This circuit of old documentation can be implemented with modern operational amplifiers. The...