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 power source was found in a 1968 Electronics World. The transistors are from that time. The...
This circuit was found in a 1986 documentation. The circuit uses 12 V relays and is powered by a...
This circuit amplifies VHF signals in the two-meter range and is very critical, especially...