This circuit was published in a recent magazine as a past project. It is a crystal radio from October 1986 Radio Electronics magazine. The article detailed the assembly.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...