This circuit was suggested by General Electric in a 1969 documentation. The transistors are of the time and the power supply is not given. Note the high supply voltage.
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...