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有人认为动圈仪表的内阻就是指量程电阻(或称限流电阻),其实不然。动圈仪表的内阻应是从动圈仪表测量机构输入端看进去的等效电阻,它包括量程电阻、温度补偿电阻和动圈电阻。本文将分别介绍这三种电阻的作用及检定中注意的问题。 XC系列动圈仪表是按最小毫伏信号所需要的灵敏度设计的。因此,为了能测量更大的信号,就要在仪表内动圈回路中串接一个电阻R_c——量程电阻,它由锰铜丝绕制而成,取值范围为200～1000Ω,通过适当选择R_c的大小,就可使不同的被测信号在仪表达到满度指示时,流过动圈的电流为同一固定值。但是,在测量较大信号时,所要求的R_c将很大,这就增大了整个动圈回路电阻,减少了工作电
Some people think that the dynamic resistance of the meter refers to the range resistance (or current limiting resistor), it is not. Dynamic instrument internal resistance should be measured from the moving coil instrument input into the equivalent resistance, which includes the range resistance, temperature compensation resistance and moving coil resistance. This article will introduce the role of these three resistors and test attention to the problem. XC series of moving coil instrument is designed according to the required sensitivity of the smallest millivolt signal. Therefore, in order to measure a larger signal, it is necessary to connect a resistor R_c, a range resistor, in the dynamic loop of the instrument. It is wound by a manganese copper wire and has a value in the range of 200 to 1000Ω. By proper selection R_c size, can make different measured signal in the instrument reaches full indication, the current flowing through the moving coil for the same fixed value. However, when measuring large signals, the required R_c will be large, which increases the resistance of the entire moving coil circuit and reduces the working power