电介质的相对介电常数ε_r不仅是静电学、电磁学、电工学中一个重要物理量,而且在工程技术中常常是反映各种材料特性的重要参数。所以我们在普物电磁学实验中安排相对介电常数测量这个内容。传统的相对介电常数测量方法中存在两个主要问题:一是由于测量电场的边缘效应及测量系统的分布电容对测量结果的影响而产生测量误差;二是必须在被测试样上涂布或粘贴导电薄膜电极,给测试、实验带来工艺上的困难(作者曾于《物理实验》1982,年第三期作介绍)。为了克服上述缺点,我们研制了一套测试设备(已有批量生产供应),不仅可以基本上消除边缘效应及分布电容对测量结果的影响,也不需在被测试样上涂布或粘贴薄膜电极,从而使测试方便而实用,适合于工业测量及学生实验。 Dielectric relative permittivity ε_r is not only an important physical quantity in electrostatics, electromagnetics and electrotechnics, but also an important parameter that reflects the characteristics of various materials in engineering. Therefore, we plan the relative dielectric constant measurement in general electromagnetic experiments. There are two main problems in the traditional relative permittivity measurement method: one is the measurement error caused by the edge effect of the measurement electric field and the distributed capacitance of the measurement system on the measurement result; the other is that the sample must be coated or Paste the conductive film electrode, the test, the experiment brought the technical difficulties (the author of “physical experiment” 1982, the third issue for the introduction). In order to overcome the above shortcomings, we have developed a set of testing equipment (already in mass production and supply), which not only can basically eliminate the influence of edge effect and distributed capacitance on the measurement result, but also do not need to coat or stick the film electrode , So that the test is convenient and practical, suitable for industrial measurement and student experiments.