Because the Faraday rotation angle increases periodically with the current measured,only a monotone region of the sinusoid could be used and the measurement range is narrowed. 由于法拉第旋转角随被测电流周期性增大，测量时只能利用正弦曲线单调变化的部分，因此限制了电流的测量范围。
Measure value over range, change measure range. 测量值超程，更改量程范畴。
Measuring value can be set up optionally in measurement. 称量值在量程范围内可任意设定。
