Quantum Measurement Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
Rev Sci Instrum. 2023 Mar 1;94(3):034711. doi: 10.1063/5.0143225.
We report a new method for determining the time constant of ac resistors with values around 10 kΩ using a digital impedance bridge for the comparison of two nominally equal resistors. This method involves adding a probing capacitor in parallel to one of the resistors to induce a quadratic frequency dependence in the real component of the admittance ratio between the two resistors. The magnitude of this quadratic effect is proportional to the self-capacitance of the unperturbed resistor, enabling us to determine its value and the associated time constant with an estimated standard uncertainty (k = 1) of 0.02 pF and 0.2 ns, respectively.
我们报告了一种新方法，使用数字阻抗桥比较两个标称相等的电阻器，来确定值约为 10 kΩ 的交流电阻器的时间常数。该方法涉及在其中一个电阻器上并联一个探测电容器，以在两个电阻器之间的导纳比的实部中引入二次频率依赖性。这种二次效应的大小与未受扰电阻器的自电容成正比，使我们能够确定其值以及相关的时间常数，其估计标准不确定度（k = 1）分别为 0.02 pF 和 0.2 ns。
