有关恒定电流的电路实验在高考物理实验题中,历年均被作为命题的重点,尤其是涉及实验中电路设计的问题,更体现出了对学生实验综合能力的要求.有些实验若能合理地利用定值电阻进行电路设计,可以起到保护电路、完善实验原理和减小或避免系统误差等方面的作用.以下根据一些实验范例对定值电阻的巧妙用法进行分类分析. Circuit experiments on constant current in the college entrance examination physics experiment, the calendar year are taken as the focus of propositions, in particular, relates to the circuit design problems in the experiment, but also reflects the students’ ability to experiment with comprehensive requirements of some experiments if we can make reasonable use of The value of the resistance of the circuit design, can play a protective circuit to improve the experimental principle and to reduce or avoid the role of system error, etc .. The following based on some experimental examples of the value of the resistance of the clever use of classification analysis.