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1.问题的由来动圈表和热电偶配套使用进行测温采用图1线路是非常普遍的。对于仪表规定的15Ω外接电阻通常都是在安装仪表时,在常温下测得热偶电阻、补偿导线电阻、铜导线电阻后用调整电阻配成的,没有考虑热偶工作时其阻值的变化情况和环境温度变化补偿导线、铜导线电阻的变化情况。这种做法对不对呢?我们认为不妥。这会给测量带来不可忽视的误差,对铂铑-铂热偶尤为突出。众所周知,测温时动圈偏转的角度a与热电偶的热电势E(t,t_0)、仪表内阻R_内、外接电阻R_外之间的关
1. The origin of the problem Dynamic table and thermocouple supporting the use of temperature measurement circuit using Figure 1 is very common. The 15Ω external resistance specified for the instrument is usually measured at room temperature thermocouple resistance, compensation wire resistance, copper wire resistance adjusted with a resistor, did not consider the thermocouple work changes in its resistance Situation and ambient temperature changes compensate for wire, copper wire resistance changes. Is this wrong? We think it is not proper. This will give measurement can not be ignored error, especially for platinum and rhodium - platinum thermocouple. As we all know, the temperature moving coil angle a and thermocouple thermoelectric power E (t, t_0), the meter internal resistance R_, the external resistor R_ off