通电螺线管绕线画法是初学这一部分内容的同学们极易出错的地方．在通电螺线管问题中,有三个方向相互关联:电流的方向、螺线管上导线的绕向、磁场的方向．安培定则(又称右手螺旋定则)对这三个方向的关系给出了科学而又生动的描述:用右手握住螺线管,让四指弯曲,跟螺线管中的电流方向一致,则大拇指所指的那端就是通电螺线管的N极．如图1． Energized solenoid winding is a place where beginners can easily make mistakes. In the energized solenoid problem, there are three directions associated with each other: the direction of the current, the direction of the wire on the solenoid, and the direction of the magnetic field. Ampere’s rule (also known as the right-handed screw rule) gives a scientific and vivid description of the relationship between these three directions: hold the solenoid with your right hand and bend the four fingers to match the direction of the current in the solenoid. The end of the thumb is the N pole of the power solenoid. Figure 1.