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仪器J2458型或J2459型示波器和电源；0－100V可变直流电源；高内阻电压表（0－100V，直流）。原理如果一块极板相对于另一块处在正电位，那么电子束将被吸向正电位
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一、演示洗衣机脱水原理1．制作方法用锥子或其它工具在塑料瓶的外周围钻上小孔（如图1），作为脱水筒使用。在瓶盖上钻上小孔，并用一横轴和小电机的轴相连（图2
在实验中，使用计时Ⅰ（S1）方式，即测量挡光条遮光时间时，会产生较大误差。其原因是：挡光条在运动时从发光器件和光敏器件之间通过。在遮光过程中，光敏器件的
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