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.
In the figure we have a simple signal tracer circuit to be coupled to the volume control of an AM...
This circuit was found in documentation from the 90s, using components from that time. The...
This circuit, obtained from old documentation, allows the recovery of sulfated batteries. The...