Obtained from a 1969 documentation, this circuit can operate at frequencies up to 500 Hz, counting up to 999. The circuit makes use of neon lamps of the time.
This circuit was obtained in an old American manual. The circuit is valid for any operational. The...
This circuit was found in the September 1992 issue of Radio Electronics magazine. The circuit does...
This simple intermittent siren circuit was found in a 1989 documentation. Both the intermittent and...