中等职业技术学校电类专业通用的《电工基础》教材中,介绍了四种正弦交流电的表示方法,即解析式法、波形图法、旋转矢量法(相量图法)、相量法。四种方法之间可以互相转化,其中波形图化解析式是学生必须掌握的方法,也是职教高考的主要考点之一。但学生在转化的具体操作中往往不知从何处入手,表达零乱,失分比较严重。本人在近几年教学中不断积累经验,归纳出“五步识图写解析式”的方法,并付诸应用,效果颇佳。《电工基础》的正弦交流电的解析表达式有 Professional universal “ELECTROTECNICS” Textbook Secondary schools TECHNICAL power class, representing the four methods described sinusoidal AC, i.e. analytical expression method, the waveform diagram, the rotation vector method (method phasor diagram), phasors. The four methods can be transformed into each other, of which waveform analysis is the method students must master, and vocational education entrance examination is one of the main test centers. However, students often do not know where to start the concrete operation of the conversion, the expression of disorder, loss of more serious. I am in teaching in recent years continue to accumulate experience, summed up the “five-step knowledge to write analytic ” approach, and put into application, the effect is quite good. “Electrician” sinusoidal AC analytical expression there