This CMOS circuit was found in a Popular Electronics from the 80's. The circuit consists of a counter that has its output activated when the selected key combination is pressed.
This linear bargraph circuit was found in the February 1992 issue of Radio Electronics magazine. The 10...
This interesting circuit, found in a 1984 documentation, captures stations in the FM band and...
This circuit is from an old Signetics documentation. It can be implemented with modern operational...