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.
Found in an Elektor from the 90s, this circuit simulates a rotary switch that provides a BCD...
This crystal shortwave radio can tune signals up to the VHF range of analog TV (which no longer...
This circuit was found in a 1987 edition of the United States' Hands On Electronics magazine. The...