“伏安法测电阻”是中学物理实验中一个重要的内容,下面我们就一起针对该实验中的重点、难点问题一一加以剖析,供同学们参考.一、基本原理根据部分电路欧姆定律R_x=U/I,知只要测出电阻两端的电压U和通过的电流I,代入表达式就可以求出被测电阻的阻值.二、两种测量电路的特点比较电压表和电流表接入方式不同,出现两种不同的测量电路,即电流表内接法和电流表外接法.在不考虑电表内阻影响时,两种接法是等效的,但如果电表内阻影响不能忽略,则不同连接方式,测量的结果 “Voltammetry resistance ” is an important part of secondary physics experiments, the following we will focus on the experiment with the key points difficult to analyze one by one, for the students to reference.First, according to the basic principles of circuit Ohm Law R_x = U / I, known as long as the measured voltage across the resistor U and through the current I, into the expression can be measured resistance of the resistance. Second, the characteristics of the two measuring circuits Comparison of voltage meter and ammeter Different ways, there are two different measurement circuits, namely the ammeter and ammeter connected to the external connection method. Without considering the meter resistance, the two connection is equivalent, but if the meter resistance can not be ignored, then Different connections, the measurement results