一电器的额定功率PN=1W,额定电压UN=100V。今要接到200V的直流电源上,问应选下列电阻中的哪一个与之串联,才能使该电器在额定电压下工作。 (1)电阻值5K,额定功率2W; (2)电阻值10K,额定功率5.0W; (3)电阻值20K,额定功率25.0W; (4)电阻值10K,额定功率2W。

一电器的额定功率PN=1W,额定电压UN=100V。今要接到200V的直流电源上,问应选下列电阻中的哪一个与之串联,才能使该电器在额定电压下工作。 (1)电阻值5K,额定功率2W; (2)电阻值10K,额定功率5.0W; (3)电阻值20K,额定功率25.0W; (4)电阻值10K,额定功率2W。


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