在电学实验题中,经常要根据题目要求对所提供的可变电阻进行选择.不少同学总感觉无规律可循,理不出思路.本文提出几个要点.供同学们参考. In electrical experiment questions, it is often necessary to select the variable resistance provided according to the requirements of the subject. Many students always feel that there is no law to follow, and there is no way of thinking. This article proposes several points. For the students to refer to.