This simple audio and RF signal tracker was found in a Japanese publication in 1967. The transistors are made of germanium and the headphone is made of crystal.
This variable power supply circuit was found in a German publication from the 1980s. The circuit is...
This simple circuit for switching RF signals was found in an RF Design from the 90s. The circuit...
We found this circuit in a 1983 English magazine, but it can be easily assembled with the BC548 or...