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伏安法测电阻是初中物理的一个重点内容,是考查学生能力的一个载体,本文就介绍几种测电阻的方法。1.用伏特表和安培表测电阻Rx,电路如图1。步骤:闭合S后,调节变阻器,测出U、I的三组不同的值。根据I=U/R Rx=U/I计算出Rx=(Rx1+Rx2+Rx3)÷3。2.只用电压表和变阻器测Rx,电路如图2。步骤:(1)闭合S,将滑片P滑到b端,电压表读数为U1(电源电压);(2)将滑片P滑到a端,电压表读数为U(2此
Voltammetry resistance measurement is a junior high school physics is a key content, is to examine the ability of students as a carrier, this article describes several methods of measuring resistance. 1. With a voltmeter and ammeter to measure resistance Rx, the circuit shown in Figure 1. Steps: After closing S, adjust the rheostat, measured U, I three different values. According to I = U / R Rx = U / I calculated Rx = (Rx1 + Rx2 + Rx3) ÷ 3.2. Only voltmeter and rheostat Rx, the circuit shown in Figure 2. Step: (1) Close S, slide the slide P to the b end, the voltmeter reads U1 (power supply voltage); (2) Slide the slide P to the a end, the voltmeter reads U