This step of good gain was obtained in an American publication of the 1980s. The circuit can be powered by voltages from 3 to 9 V and the FET can be of almost any type.
This simple circuit can be used in a robot that follows the light directly feeding a small motor....
We found this circuit in Radio Electronics magazine from May 1962. The circuit uses rectifier...
We found this circuit in Mullard's 1960s transistor manual. The circuit oscillates at 800 Hz, the...