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电路分析与计算是《恒定电流》单元中的重要内容,其思想方法贯穿整个电路研究的始终,加强训练将有助于培养学生良好的思维品质和解决问题的能力.一、动态电路分析例1如图1所示电路中,当滑动变阻器的滑动触点向上移动时,电流表、电压表的示数怎样变化?解析当滑动片向上移动时,变阻器R_3阻值增大,外电路总电阻变大,根据I=E/(R+r),可判断总电流减小,U_内=Ir减小,路端电压增大,即电压表的示数变大;电流表的示数是滑动变阻器中的电流,
Circuit analysis and calculation is the “constant current” unit of the important content of its thinking method throughout the entire circuit research, strengthen training will help to develop students’ good thinking quality and problem solving ability .A dynamic circuit analysis example 1 As shown in Figure 1 circuit, when the sliding rheostat sliding contacts move up, ammeter, voltmeter how the number changes? Analysis When the sliding plate moves upward, rheostat R_3 resistance increases, the total external circuit resistance becomes larger , According to I = E / (R + r), can determine the total current decreases, U_ within = Ir decreases, the road side voltage increases, the voltmeter shows a larger number; ammeter shows the slide rheostat Of current,