When a current is supplied to a thin wire having smaller heat capacity, the temperature of the wire easily increases due to the principle of Joule heating. The temperature distribution in the wire has constituted an important issue for thin wire application. This paper reports a method to predict the temperature distribution in a thin wire through which current is flowing. The potential drops at the surfaces of thin Cu wires with diameters of 25 µm and 100 µm were measured. For these measurements the points of contact were close together, enabling us to measure the temperature dependency of the electrical resistivity of the wire. On the other hand, potential drop measured between the points of contact much further apart provided the information on the temperature distribution in the wire. By assuming the symmetric and parabolic temperature distribution, the temperature distributions in the Cu wires of 25 µm and 100 µm thick were predicted using the potential drop measurements made with the points of contact much further apart. The temperature distributions predicted were in good agreement with those measured by infrared thermography. The validity of the proposed method was also verified by conducting a similar experiment on Fe wire having a diameter of 100 µm.

当电流提供给具有较小热容量的细线时，由于焦耳加热的原理，线的温度容易升高。导线中的温度分布已经成为细线应用中的重要问题。本文报告了一种预测电流流经的细线中温度分布的方法。测量了直径为25 µm和100 µm的细铜线表面的电位降。对于这些测量，接触点靠在一起，这使我们能够测量导线电阻率的温度依赖性。另一方面，在相距更远的接触点之间测得的电位降提供了有关导线中温度分布的信息。通过假设对称和抛物线的温度分布，使用在接触点相距更远的位置进行的电势降测量，可以预测25 µm和100 µm粗的Cu线中的温度分布。预测的温度分布与通过红外热成像法测得的温度分布非常吻合。通过对直径为100 µm的铁丝进行类似的实验，也验证了该方法的有效性。