We found this circuit in an old documentation. Its purpose is to turn on warning lights when the vehicle in a garage touches or passes a sensing bar preventing it from hitting the wall.
This circuit, suggested by Signetics can be used as a shield. Modern operational can be employed...
In the figure we have a typical voltage follower. In a voltage follower the voltage gain is...
This 2001 circuit uses common transistors and can be used in an electronic lock. The relay trips...