This circuit was found in an American documentation from 1969. Indications of the used transistors are not given, but general-purpose types can be tested.
This circuit from Delta Products was published in the May 1974 Radio Electronics magazine. The...
This circuit that uses only transistors that are still common was found in a 1995 documentation. The TIP41...
This new Texas Instruments component consists of an inductive proximity detector that can be used...