使用万用电表欧姆档测量电阻时,应选择合适的量程,尽可能使测量值位于刻度盘中央、对此,许多现行教科书仅仅指出这样做的目的是为了减少测量误差.但为什么能减少测量误差,却未见进一步的说明,笔者发现,若从欧姆档的电路原理出发,经过简单的推导,所得到的误差曲线,能较好地解释欧姆档的使用规律,现介绍如下: When measuring the resistance using the multimeter’s ohm range, you should select the proper range so that the measured value is as far as possible in the center of the dial. For this reason, many current textbooks only point out that the purpose of doing so is to reduce the measurement error. But why can the measurement be reduced? The error, but no further explanation, the author found that if you start from the circuit principle of Ohm file, after a simple deduction, the error curve obtained can better explain the use of Ohm file, is described as follows: