This circuit is suggested by American documentation from 1970. It makes use of transistors of the time but can be implemented with modern equivalent transistors.
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...