This source whose voltage depends only on the zener diode used, can supply currents up to about 3 A. The transformer has a secondary from 1 A to 3 A according to the desired current. The diodes can be 1N4002 for current up to 1 A and 1N5402 for larger currents. The transistor must be equipped with a heatsink. The circuit is from the book Mechatronics Sourcebook by Newton C. Braga, published in the United States.
