Abstract: Current pulses are conducted through an inductance by means of a switching transistor. The switching transistor is controlled by means of an amplifier and pulse shaper circuit in such a manner that a constant average direct current flows in a closed loop comprising said inductance and a recovery diode, resulting in a regulated, constant output voltage across two Zener diodes. This allows a particularly effective operation with relatively low power losses in said switching transistor as compared to the utility current at the output terminals, and the circuit operates reliably in a wide range of operating voltages.