提高锁相放大器测量交流磁化率精度的方法

Improving accuracy of AC susceptibility measurement with lock-in amplifier

在交流磁化率的测量实验中,互感法是常用方法,通常是利用线圈绕组和锁相放大器组合来测量样品在线圈中引起的电感变化.但这种方法其背景信号随绕组的增加而增大.本文采用2对线圈绕组并把两初级线圈反绕、两次级线圈同向绕的设计,减小背景信号,实际使用证明,经改进后测量灵敏度和测试精度都有很大提高.

Mutual inductance method is widely used in measuring ac susceptibility.A commonly used way is to use coil winding and lock-in amplifier together to measure the inductance changes caused by samples in the coils.However,in this method,background signals increase with the increasing number of windings.In this paper,by using two pairs of coil windings,including two reverse-winding primary coils and two coherent-winding secondary coils,background signals are decreased distinctly.The experiment also proves that the change largely improves the measuring sensitivity and testing accuracy.