一、引言在电学的实验教学过程中往往存在一些缺陷,例如,示教大型灵敏电流计灵敏度不够,10μA以下的瞬时峰值电流显示不出来,20μA峰值电流显示可见度仍然很小,显示反应慢,指示值与实际电流不能及时同步,会出现由于指针系统的惯性而引起的错误指示,没有电流指针还会左右摆动,电流的方向性无法准确判断;还有在实验演示 I. INTRODUCTION There are often deficiencies in the experimental teaching of electricity. For example, the sensitivity of teaching a large sensitive galvanometer is not enough. Instantaneous peak current below 10μA is not displayed. The visible current of 20μA peak current is still very small, indicating that the response is slow. The value and the actual current can not be synchronized in time, there will be an error indication due to the inertia of the pointer system, no current pointer will swing around, the directionality of the current can not be accurately judged; also in the experimental demonstration