This circuit is based on an unusual component today. It demodulates a 10.7 MHz FI signal and was found in 1980s documentation.
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...