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.
With this circuit, a relay can be activated from an alternating signal with frequency up to a few...
With this circuit the visually impaired can easily locate important places inside the house, such...
In the figure we have the way to use the transistors of an old-paired pair as a trigger circuit. The...