微[物理]电阻四线量测法.pdfVIP

除了在第3.2 节介绍的所有低电压测量中要考虑的问题之外，在低电阻的测 量中更容易引进附加的误差源，其中包括引线电阻、非欧姆接触以及器件的 加热问题。这一节将要介绍这些误差源以及将其消除或者降至最小的各种方 法。此外还要介绍其它一些测量中要考虑的因素，包括干电路测试和电感性 器件的测试等。 3.3.1Lead Resistance and Four-Wire Method 引线电阻和四线方法 Resistance measurements are often made using the two-wire method shown in Figure 3-14. The test current is forced through the test leads and the resistance (R) being measured. The meter then measures the voltage across the resistance through the same set of test leads and computes the resistance value accordingly. 电阻的测量常常使用图3-14 所示的两线方法来进行。我们迫使测试电 流流过测试引线和被测电阻（R ）。然后仪表通过同一套测试引线来测量电 阻两端的电压，并计算出相应的电阻数值。 The main problem with the two-wire method as applied to low resis tance measurements is that the total lead resistance (RLEAD) is added to the measurement. Since the test current (I) causes a small but significant volt age drop across the lead resistances, the voltage (V ) measured by the M meter won’t be exactly the same as the voltage (VR) directly across the test resistance (R), and considerable error can result. Typical lead resistances lie in the range of 1m. to 10mΩ, so it’s very difficult to obtain accurate two- wire resistance measurements when the resistance under test is lower than 10. to 100. (depending on lead resistance). 两线测量方法用于低阻测试时的主要问题是测量结果中增加了引线的 总电阻（RLEAD ）。由于测试电流（I ）在引线电阻上产生了一个小的、但是 很重要的电压降，所以仪表测量的电压（VM ）就不会和被测电阻（R ）上的 电压完全相同，于是产生了相当的误差。典型的引线电阻在1mΩ 到10mΩ 的范围内，所以当被测电阻小于10Ω 到100Ω 时，就很难用两线测量方法来 获得准确的测量结果（取决于引线电阻的数值）。 Due to the limitations of the two-wire method, the four-wire (Kelvin) connection method shown in Figure 3-15 is generally preferred for low resistance measurements. These measurements can be made using a DMM, micro-ohmmeter, or a separate current source and voltmeter. With this configuration, the test current (I) is forced through the test resistance (R) through one set of test leads, while the voltage (V ) across