telephone-line-fault-testing

代码说明：

  电话线出现断线或短路故障时，线路的阻抗则发生很大变化，利用电桥法测试出电阻的大小，进而得出线路故障的地方(Telephone lines appear disconnection or short circuit fault, the line impedance is changed, test out the size of resistance by Wheatstone bridge method, and then draw the line fault place )