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.
The presented circuit was found in a 90’s Electronic Engineering. The circuit is based on CMOS...
We find the original version of this circuit in an English publication (1986). It is a...
Found in a 1990s Electronics Now, this circuit uses a period-specific integrated circuit that...