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 was found in an old Electronic Design. It makes use of sidacs and operational not very...
This 2009 circuit is a bilateral call warning. Easy to build, using light communication between two...
This circuit for shunt motors was found in an American 1980s documentation. The SCR should be rated...