Based on Radio Shack 276-137, this circuit was found in the December 1995 issue of Electronics Now magazine. The circuit drives an LED but could use a relay instead.
This circuit trips when a negative pulse is applied to its input or when the voltage drops below a...
This is an old 1988 circuit consisting of a timer or time control for exposing silk-screen arrays. The...
This circuit was taken from an old American documentation. It can be built with modern op amps. The...