This 9-pixel circuit has been implemented with 9 LDRs and can be coupled to a processing system for an elementary artificial eye. The circuit is from Radio Electronics, November 1986.
This circuit that draws 1 out of 8 LEDs was found in an 80's American documentation. The circuit...
This protective circuit for power lines was found in a Radio Electronics from November 1957. The...
In figures 1 and 2 we have two current drains that can be made with operational amplifiers and...