Found in an American documentation from 1969, this astounding circuitry makes a relay operate on 3 Hz cycles. The relay is of the high voltage type of the time.
This sensitive motion sensor with inductive sensor was found in a 90s Elektor. The circuit uses only...
This simple balance indicator for sound equipment was found in a 1982 documentation. The M1...
This circuit was found in a 1992 documentation. It uses a photo diode as a receiver and an...