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 activates an output, which can be a lock, only when a card containing the programmed code...
This circuit was found in Popular Electronics from 1993. The 1458 consists of a double 555. The...
This is a Serial In - Parallel Out or Serial Out [SIPO or SISO] shift register using the...