This grounding test circuit was found in an American 80's documentation. The circuit is for the 110 V power grid but can be changed to the 220 V power grid.
This circuit produces an intermittent ring tone being triggered directly by the telephone line. However,...
We found this circuit in the March 1991 issue of Radio Electronics magazine. The integrated...
This 1964 Electronic Design circuit uses a photo-FET as a sensor. The component is rare today. |...