We found this receiver on a single chip in the 1976 Siemens integrated circuits manual. The circuit is of the super heterodyne type using ceramic filter in the IF.
This circuit activates a relay when the sensor receives light. The sensor can be any common LDR,...
We found this circuit in a 1980 documentation. With basic changes, including transistors that were...
When a small air current reaches the piezoelectric sensor, a small audio signal is generated and...