We found this circuit in the July 1969 Radio Electronics magazine. The circuit uses a coupler made with a lamp and an LDR. The power of the lamp determines the types of diodes.
This circuit turns on a lamp after the time set on the potentiometer. The circuit is from a Radio...
This circuit was suggested by General Electric in a 1969 documentation. The transistors are of the...
Found in a 1991 PE Hobbyst Handbook, this unit can actually supply 1.5 A with the LM317 and 3 A...