This circuit appears at various points on this site and in this section and can be designed with almost any operational amplifier. This version is from an American documentation from 1975.
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...