The operating circuit includes a current converter (3) coupled to a rectifier circuit (5), used for charging a capacitor (14), which is discharged via the release magnet winding (11) upon operation of a controlled switch (12). The switch is connected in series with the winding. A charging resistance (15) is connected in series with the capacitor, with a resistance value which is higher than the resistance of the release magnet winding. A diode (17) across the charging resistance is biased in the direction of the discharge current.