物理教学中常采用小磁针和铁粉来模拟磁场的分布情况,研究通电直导线周围的磁场也可以采用相同的方法。然而单根通电直导线产生的磁场很微弱,看不出铁粉分布规律,小磁针转动也不明显,若小磁针靠得太近又会相互干扰,实验可视性很差。而通过增大电流来增强磁场效果也很有限,电流过大也会损坏电源。根据磁场的叠加原理,将多根电流方向相同的直导线绑在一起可以产生比单根直导线更强的磁场。本 In physics teaching, small magnetic needles and iron powder are often used to simulate the distribution of the magnetic field. The same method can be used to study the magnetic field around the power-conducting straight wire. However, the magnetic field generated by a single power wire is very weak, can not see the distribution of iron powder, small needle rotation is not obvious, if the small magnetic needle too close again will interfere with each other, the experimental visibility is poor. By increasing the current to enhance the magnetic field effect is also very limited, the current is too large will damage the power supply. According to the principle of magnetic field superimposition, it is better to tie more than one straight wire with the same current direction to produce a stronger magnetic field than a single straight wire. this