This is the receiver circuit for the transmitter of the previous circuit using an integrated circuit of the time. The circuit is in the same Radio Electronics magazine as August 1986.
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...