用锁相放大器测量材料的介电参量

Measuring dielectric parameters with lock-in amplifier

采用I-V法的数字电桥通过测量被测对象的交流电流和电压及两者之间的相位差,根据物理原理可得到描述材料特性的一系列介电参量.在充分理解实验技术原理的基础上,由交流信号源和锁相放大器等通用仪器组合实现数字电桥测量功能,且用数字电桥测量结果检验组合系统的科学性.同时,利用数字电桥不同测量模式的实验结果验证由最基本实验数据经过数理分析所得到介电参量的正确性.组合系统不仅有助于理解阻抗测量分析原理,还可根据需要拓展实验测量功能用于特定条件下材料介电特性研究.

The digital bridge using I-V method can be applied to obtain a series of dielectric parameters,which describes the material characteristics by measuring the alternating current and voltage and the phase difference between them.Based on fully understanding of the principle of experimental technology,the function of digital bridge was realized by using AC signal source and lock-in amplifier,and the practicability of the combined equipment was checked by the results from digital bridge.The dielectric parameters obtained by analyzing the original data were verified by the individual results of different measurement modes of the digital bridge.The combined equipment was valuable for understanding the principle of impedance measurement and its data analysis,and it would expand the measurement function for the study of AC impedance under specific conditions.