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赏析2012年江苏省各大市中考试题,从中发现电学计算题中电热器的调档问题仍是中考的常考内容.所谓电热器的调档也就是通过调节电路的阻值改变电热器的发热功率.根据P=UI=U~2/R知,在电压不变的情况下,只要改变接入电路中的阻值R,就可以改变电热器的发热功率.电热器的调档电路大体有三种设计方案.
Appreciation of the 2012 Jiangsu province major city in the examination questions, found that the electrical calculation of the problem of electric heater is still the entrance examination in the exam content is often called the so-called electric heater is the transfer of documents by adjusting the resistance of the circuit to change the heating heater Power.According to P = UI = U ~ 2 / R know, under the condition of the voltage invariable, just change the resistance R in the access circuit, can change the heating power of the electric heater. Kind of design.