This circuit uses an optical coupler called Raystor created by Raytheon in the 1960s. The circuit uses components from the era that can be changed. The current is low.
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...