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.
This circuit, found in a 1994 documentation, uses 20 A 2N5448 triacs or equivalent and should be...
This circuit uses two Raytheon RC4558 operational amplifiers that are similar to the 741. The...
We found this circuit in a 1994 documentation. It can be implemented with the indicated...