九年义务教育初中物理第二册中《家庭电路电流过大的原因》一节的两个演示实验,由于电源电压220V,使有的师生害怕触电而不敢开设这个实验。为此,我研制了既安全可靠又能说明原理的示教板。 The two demonstration experiments in the “Cause of too much current in the home circuit” in the second-year compulsory education junior high school physics book, because of the power supply voltage 220V, some teachers and students are afraid to get an electric shock and dare not open this experiment. For this reason, I have developed a teaching board that is both safe and reliable and can explain the principle.