This sophisticated repellent uses a double 555. We find it in an American documentation from the 80's. The circuit can be powered by batteries or source included in the diagram.
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...