在高中物理必修课本第二册“串、并联电路”教材中，有两个用来定性演示电路功率分配的实验。课本中这两个实验是分别用两个演示电路板来完成，使用不太方便，换用灯泡做第二个实验时，学生容易产生误解。笔者对本实验原理进行了认真地分析，设计了一个电路，只需改变开关的位 There are two experiments that are used to qualitatively demonstrate circuit power distribution in the textbook “Serial and Parallel Circuits” in the second volume of the high school physics compulsory textbook. The two experiments in the textbook are done by using two demo boards, which are not easy to use. When using a light bulb for a second experiment, students are prone to misunderstandings. The author carefully analyzed the experimental principle and designed a circuit that only needs to change the position of the switch.