在现代人类生活中,电动机(图1,德国邮资机戳)用途广泛。凡需要动力的地方,如工厂中各种机床。日常生活中使用的电冰箱、电吹风、电扇、电传机(图2)等,都离不开电动机。1820年4月某一天,丹麦物理学家奥斯特在课堂上演示物理实验时偶然发现放在通电导线下方的小磁针发生偏转(图3)。这一细节并没有引起在场的其他人注意,奥斯特却敏锐地观察到了。由于他很长时间以来一直在寻找电和磁的联系,这一发现使他非常兴奋。之后他又以不同方式做了类似实验,证实通电导体的周围空间有磁效应,存在着磁场。 In modern human life, electric motors (Figure 1, German stamping machine stamp) a wide range of uses. Where you need power, such as a variety of machine tools in the factory. Refrigerator used in daily life, hair dryer, fan, fax machine (Figure 2), etc., are inseparable from the motor. One day in April 1820, the Danish physicist Oster, who occasionally demonstrated physical experiments in the classroom, found that the small magnetic needle placed under the conductive wire was deflected (Figure 3). This detail did not draw the attention of the others present, but Auster was keenly aware of it. This discovery made him very excited because he had been looking for the connection between electricity and magnetism for a long time. After that he did a similar experiment in different ways, confirming the magnetic effect of the surrounding space of the conducting conductor and the presence of a magnetic field.