欧姆定律中由于电压表和电流表的量程范围确定滑动变阻器的取值,这类型的题目中由于两表的量程和测量关系的改变会使变阻器的取值发生一定的变化,而学生在处理此类题目时却容易忽视条件发生错误.怎样关注条件,正确的得出答案,就此举例分析.例1如图1所示的电路中电源电压 Ohm’s law due to the voltmeter and ammeter range to determine the scope of the sliding rheostat value, the subject of this type as the two tables range and measuring changes in the relationship between the rheostat value will have some changes, and students in dealing with such Problem is easy to ignore the conditions of the error. How to pay attention to conditions, the correct answer, for example analysis. Example 1 shown in Figure 1, the power supply voltage