This protective circuit for power lines was found in a Radio Electronics from November 1957. The transistor used can be any general-purpose transistor such as the CK722.
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...