Suggested by General Electric in a 1967 publication, this circuit uses the D13T1, an uncommon SCR today. This component is triggered by the anode.
This is yet another simple LED driving game circuit that appears in several other versions on this site....
We found this circuit in a manual of optoelectronics from Texas Instruments. In it photodiodes or...
This interesting circuit is from a 1988 documentation. It is a matrix of diodes that converts...