山东省96年中考题目中,整个试卷的最后压轴题是一道有代表性的电路计算题.题目如下:在如图所示的电路中,滑动变阻器 R 的最大阻值是20欧,电源电压为8伏.(1)当滑动变阻器的触片 P 移至 a 端时,将 S_1闭合,S_2断开,电流表的示数为0.8安;(2)当滑动变阻器 In the 96-year senior middle school entrance examination in Shandong Province, the final title of the entire paper was a representative circuit calculation problem. The topic is as follows: In the circuit shown in the figure, the maximum resistance of the sliding rheostat R is 20 ohms, and the power supply voltage is 8 V. (1) When the contactor P of the sliding rheostat moves to the a side, S_1 is closed, S_2 is opened, the ammeter is 0.8 Amp; (2) When the sliding rheostat