Found in an April 1977 Radio Electronics issue, this circuit uses the well-known XR2206. The C1 values for the various frequency bands are given next to the diagram.
This immobilizer circuit for the car was found in the Radio Electronics magazine of December 1976....
This circuit allows the activation of a remote telephone bell made with a common piezoelectric capsule. The...
This circuit can act as a receiver for the transmitter of the previous circuit. We found it in...