This circuit, with printed circuit board, is from an article in Radio Electronics magazine from May 1971. The circuit uses the C106 which was already a common component at the time.
Found in a 1980s documentation, this circuit works with a 12V relay. The horn is the boat's own. |...
This circuit was found in Delco documentation from 1966. The components are from that time....
This circuit, which can be built with several CMOS gates, was found in the March 1996 issue of...