Found in a 1980s manufacturer documentation, this circuit can be used as an optical shield. The integrated circuit is from the era and modern equivalents can be tried out.
This simple CMOS metronome circuit can be mounted in a small box, providing both sound and light...
Although indicated in the original publication of the 1980s as a capacitance switch, the circuit...
In the figure below we have a simple way to do chroming, silvering or another type of...