This circuit is from 1975 documentation. Transistors such as 2N3055 can be used and the transformer is of a special type. R1 is 200 ohms and R2 is 10 ohms.
This circuit is from a Radio Electronics from April 1965. It uses an incandescent lamp, and the...
This circuit was found in a 1968’s publication and uses germanium transistors. The characteristic...
This is a single IC voltage regulator that can acts in the range from 1.2 to 20 V. Output currewnt is up to...