This circuit recognizes a tone determined by the tuned input circuit (R3 / R4 / C2). The circuit was found in Radio Electronics from the 90s. The 4046 is not a common component today.
This circuit uses an unusual component today which is the integrated circuit. We found this...
This circuit was found in an old American documentation. The operational used is of the...
In figure 1 we have an application for NLAS5113, a new device from On Semiconductor...