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对电路的研究,在新课标教材中以纯电阻的串、并联电路的题型较多,对于非纯电阻电路涉及的很少。同学们在解答非纯电阻电路问题时会经常出错。下面就这类问题举出一例,请同学们参考。如图1所示,电源的电动势E=110 V,电阻R_1=21Ω,电动机绕组的电阻R_2=0.5Ω。当开关S断开时,电阻R_1的电功率P_1=525 W,当开关S闭合时,电阻R_1的电功率P_2=336 W,求:(1)电源的内电阻;(2)当开关S闭合时电动机的发热功率。解析:(1)设电源的内电阻为r,由题意和闭合电
Research on the circuit, in the new course materials to pure resistance string, parallel circuit more questions, for non-pure resistance circuit involved in the few. Students often make mistakes in answering questions about non-pure resistance circuits. Here’s an example of such issues, please students reference. Shown in Figure 1, the power of the electromotive force E = 110 V, resistance R_1 = 21Ω, the motor winding resistance R_2 = 0.5Ω. When the switch S is off, the electric power P_1 of the resistor R_1 is 525 W. When the switch S is closed, the electric power P_2 of the resistor R_1 is 336 W, and it is found that: (1) the internal resistance of the power supply; (2) The heating power. Analysis: (1) set the internal resistance of the power supply r, by the ins and outs