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 circuit was found in old documentation and can be implemented with other operational...
This circuit was found in the December 1984 issue of Radio Electronics magazine. The circuit has a...
This Testa o Croce (name in Italian) was obtained from an Italian magazine in 1994. The circuit can...