The source of the figure was found in a 1981 magazine and is recommended for the experimenter's bench. The source is conventional with full-wave rectification made by 4 diodes that can be of the type 1N4002 or equivalent, and the filtering by a 16 V electrolytic capacitor whose value must be the largest possible. The reader suggests a minimum value of 470 uF, but if in the supply of radios or small amplifiers there is a snoring manifestation, this capacitor must be increased. A 100 R x 5 W wire pot connected to the output allows the output voltage to vary between 0 and the maximum depending on the load.
