Using a capacitor as a sensor, this circuit was found in the 1989 Radio Electronics Experimenter magazine. The circuit must be assembled in a shielded box.
We found this circuit in a 1986 documentation. It is based on TTL integrated circuits that can be...
This circuit was obtained from a 1968 Philips publication. The transistors are of the time. Dual...
This project, found in a 1981 documentation, consists of an interesting adaptation of the test...