图1欧姆表测电阻较之于伏安法测电阻更快捷、简便,用多用电表欧姆挡来测量电阻、探测电学黑箱是高考中的重要实验,新课标高中物理人教版选修3-1中不仅要求学生会用欧姆表测电阻,而且介绍了欧姆表的简单电路(如图1所示)和设计原理.这里所用电流计G的满偏电流为Ig,内阻rg,调零电 Figure 1 Ohm metering resistance is faster and easier than volt-ampere metering resistance. Multimeter ohm resistance is used to measure resistance. Detecting electrical black box is an important experiment in the college entrance examination. The new curriculum standard high school physics teaching board elective 3-1 Not only does the student need to measure resistance with an ohmmeter, but also introduces a simple circuit (shown in Figure 1) and design principle of the ohmmeter. The full bias current of the galvanometer G used here is Ig, internal resistance rg, zero