用红外测温仪观察二极管板流引起的阴极降温现象

为了观察由板流引起的灯丝温度下降现象，利用红外测温仪对理想二极管灯丝温度作了精密测量。由于忽略了板流，导致阴极灯丝温度下降，致使测得的金属逸出功存在着大约-1.86%的系统相对误差。实验验证了当灯丝电流和板流较小时，测不出灯丝温度随板流的变化。当灯丝电流为0.74A以上时，可以明显地观察到输出板流后，灯丝温度要比板流为0时低（1～2）K，此结果与预测值十分相符。

Observation of cathode temperature-drop phenomenon caused by diode board-current with IR thermometer

In order to observe the phenomenon of the filament temperature drop caused by the board-current, the ideal diode filament temperature was detected precisely with an infrared thermometer. Since the cathode filament temperature drop caused by the boardcurrent was neglected, it resulted in about-1.86% system relative error in the measured metal work function. The phenomenon was found through a theoretical analysis, and it was verified by an experiment.When both the filament current and board-current are lower, the variation of the filament temperature with the board-current is not measurable; when the filament current is above 0.74A, it can be clearly observed that the filament temperature is (1～2)K lower than that of zero board-current after the board-current is outputted.