| 摘要 |
To adjust and/or regulate the output power of an energy source, a signal corresponding to the instantaneous output power is generated. In a microwave oven, consisting of a magnetron (12) and a direct-current supply source (14) connected to it, the signal (Vv) corresponds to the anode current drawn by the magnetron (12) a voltage equivalent to this current. The operating time is subdivided into a sequence of equal time intervals, each time interval corresponding to a predetermined number of mains alternating-current periods. Dependent on the signal determined, the number of alternating-current periods, which feed the direct-current supply source during each time interval, in order to keep the output power at a value or to adjust it to such a value, is determined. The number of alternating-current periods determined in each case is fed from the mains into the power supply source (14) each time it switches at the zero crossing of the current. The switching is carried out in such a manner that the alternating-current periods needed for feeding during one time interval are essentially uniformly distributed over this time interval. <IMAGE>
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