The sensor of this circuit is a photodiode. Equivalent operations can be used, and the instrument can be replaced by the lower current range of a standard multimeter.
This converter or inverter uses components that are still common. The transformer is the type...
This new Texas Instruments component consists of an inductive proximity detector that can be used...
This circuit is from 1992 documentation. The transistor can be a TIP42 with a good heat sink for...