Surveying the internal resistance of a sensitive electric currentmeter is a rather difficult and complicated electromagnetic experiment which is hard to get a high precision.
灵敏检流计内阻测量实验是电磁学实验中一个比较复杂有相当难度的实验，难就难在如何提高测量精度。
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Theinstrument is designed based on electromagnetic theory and principle of equilibrium in mechanics and composed of a timer, a current regulator and meter, control circuits and two-arm pinchers.