This circuit is from a 1966 NASA documentation. The circuit uses a photodiode as a sensor. The other components are from that time.
In the original 1992 application, this passive circuit was intended for use in the car. At that...
This electronic rheostat with SCR was found in the June 1964 Radio Electronics magazine. The SCR...
This circuit was found in Radio Electronics magazine from the 90's. The circuit is for small NiCad...