第6课时练习使用多用电表【考纲解读】1.了解电表改装的原理与方法.2.了解多用电表的构造和原理，掌握多用电表的使用方法.3.会使用多用电表测电压、电流及电阻.4.会用多用电表探索黑箱中的电学元件．【知识要点】一、电流表与电压表的改装1．改装方案改装为电压表改装为大量程的电流表原理串联电阻分压并联电阻分流改装原理图INCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\1020.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\1020.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\1020.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\鹿晴晴\\2015\\一轮\\Word\\一轮\\物理\\1020.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\杨营\\2015\\word\\微课\\物理\\物理通用\\1020.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\1021.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\1021.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\2015\\Word\\物理\\一轮物理\\1021.TIF"\*MERGEFORMATINCLUDEPICTURE"E:\\鹿晴晴\\2015\\一轮\\Word\\一轮\\物理\\1021.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\杨营\\2015\\word\\微课\\物理\\物理通用\\1021.TIF"\*MERGEFORMATINET1分压电阻或分流电阻U＝Ig(Rg＋R)故R＝－RgIgRg＝(I－Ig)R故R＝改装后电表内阻RV＝Rg＋R>RgRA＝
