Found in an EDN from the 1980s, this circuit uses a double 555. The circuit activates a relay that controls a horn or siren. Next to the diagram we have the timings.
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...