This circuit was obtained from 1967 documentation. It uses a sensor to determine the trigger point. The components are of the time, difficulty to obtain these days.
We found this circuit in the April 1975 Radio Electronics magazine. The circuit has a latch and...
We found this sophisticated home alarm in a 1994 documentation. The circuit supports sensors of...
This circuit was found in the 1991 Electronics Experimenter's Handbook. It activates a relay when...