This circuit that can be activated by light or heat was found in an old American documentation, but the components it uses are perfectly current. The power transistor shall be fitted with a heat sink.
This circuit was found in a RE Experimenter Handbook from the 90's. The components are of the...
Using an integrated voltage regulator as a reference, we can control several power transistors of type...
This MW radio circuit with varicap tuning was found in an English documentation from 1989. The...