在交流电的教学中,用手摇发电机得到交变电流点亮小电珠等演示实验是必要的,它能给学生以实感。但是学生看过演示后,对正弦交变电流的产生并不很清楚。一般教师都用挂图逐一地讲解。由于挂图是静止不动的,讲解的效果不理想。如果用以下程序作为辅助手段,可以形象地再现线圈在磁场中转动的情况及各时刻对应的电动势的方向及大小,帮助学生更好地理解正弦交变电动势是如何产生的、交流电的相位、相位差及频率的物理意义是什么,比起以往用挂图讲解优越得多。现介绍如下,以期和兄弟院校的同志们 In the teaching of AC, it is necessary to use hand-cranked generators to obtain alternating currents and light small beads to demonstrate experiments. It can give students a sense of reality. However, after students saw the demonstration, the generation of sinusoidal alternating currents was not very clear. Teachers generally use wall charts to explain one by one. Because the wall chart is still, the effect of the explanation is not ideal. If the following procedure is used as an auxiliary means, it is possible to visually reproduce the rotation of the coil in the magnetic field and the direction and magnitude of the corresponding electromotive force at each time to help students better understand how the sinusoidal alternating electromotive force is generated, the phase and phase of the alternating current. What is the physical meaning of the difference and frequency, much better than using the wall chart to explain. Here are the introductions below, with a view to comrades from brothers and universities