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 simple lie detector was found in Popular Electronics. Transistors are commonly used. The...
This one-transistor alarm can be used with much more sensors than the two shown by the figure....
This circuit was obtained in a 1975 documentation. The maximum frequency depends on the diodes and the...