中文摘要：

SM-30磁化率仪具有仪器轻巧、使用方便、测定快捷等多项优点,因此在磁法勘探中具有广泛的应用。从SM-30的原理框图流程入手,简述了SM-30磁化率仪内部的各元件组成及其工作流程,并介绍了推断模式的操作流程,最后从电气部分推导了SM-30磁化率仪内部振荡器的频率变化与外部待测物体磁化率间的线性关系,揭示了SM-30磁化率仪的工作原理,让广大地质工作者能够更好地掌握及使用SM-30磁化率仪。

英文摘要：

SM-30 magnetic susceptibility instrument has multiple advantages that it＇s light-weight ,easy to use and rapid to measure. Accordingly, SM-30 is widely applied in magnet-ic prospecting nowadays. This paper starts with the principle diagram of SM-30, briefly de-scribes its internal components and working process,and introduces the operating principle of the extrapolation mode of SM-30. Then,this paper analyzes the linear relation between the frequency changes of the oscillator circuits inside SM-30 and the magnetic susceptibility of the measuring external object from the view of electricity,and reveals the operating prin -ciple of SM-30,which could offer help for more geophysical workers to master and use SM-30