摘要
由经典观点出发，利用麦克斯韦著名假设之一，变化电场产生变化磁场，导出运动电荷的磁场计算公式。
Starting from classical viewpoint and making use of Maxwell's famous postulate,that is,changing electric field excites changing magnetic field,the calculation formula for the magnetic induction of a moving charge is derived,and further,the Biot Savart Laplace law is obtained.
