在闭合电路中，当某一电阻的阻值发生改变时，常会使电路中的电流表、电压表的读数发生相应的变化．这类问题是近几年中考多次考查的知识点．多数同学对这类问题颇感棘手，原因就在于电路中的变化量多，而这些变化量之间又相互制约．因此同学们往往难以作出准确的分析判断．解 In a closed circuit, when the resistance of a certain resistance changes, it will often cause a corresponding change in the reading of the ammeter and voltmeter in the circuit. This kind of question is a knowledge point that has been examined many times in recent years. Most students are very troublesome with this type of problem, because the circuit has a lot of changes, and these changes are mutually restricted. Therefore, it is often difficult for students to make accurate analysis and judgment. solution