An economical compact power supply for a superconducting magnet is described. This source operates on the principle of a pulse-controlled regulated power supply. The current may be regulated from 0 to 300 amp, with an instability not exceeding 10** minus **6 at 300 A. For a magnet inductance of 1 H the ripple factor does not exceed 10** minus **7. No more than 550 W of power is drawn. A schematic is provided.