| 摘要 |
PURPOSE:To constantly reduce predetermined input power by detecting the difference between the current value of a semi-conductor switching element and the current value of a resonance condensor so as to control the current of the switching element. CONSTITUTION:A cooker 9 is electromagnetically heated via a resonance circuit comprising a power source 1, a semiconductor switching element 8 and a resonance condensor 7, etc. Operation of the switching element 8 is controlled by a control circuit 11. The current of the switching element 8 and the current of the resonance condensor 7 are detected by first and second current detecting means 10a, 10b, respectively, and the difference between both current values is calculated by an arithmetic circuit 13. Should the difference value exceed a reference value, the current of the switching element 8 is always controlled to a constant value via a comparing circuit 14, a timer circuit 15, a driving circuit 11 and the like regardless of the kind of the cooker 9 or fluctuation of the power source 1, etc. |
