如图所示电路中,电阻R1、R2、R3的阻值都1欧姆,R4、R5的阻值都是0.5欧姆,ab端输入电压U=6伏,当cd端接电压表时,其示数是_.

问题描述:

如图所示电路中,电阻R1、R2、R3的阻值都1欧姆,R4、R5的阻值都是0.5欧姆,ab端输入电压U=6伏,当cd端接电压表时,其示数是______.

当cd端接电压表时,R1、R2、R3串联,此时R4、R5相当于导线,电压表测R2两端的电压,则得电压表的示数:UV=

R2
R1+R2+R3
U=
1
1+1+1
×6V=2V
故答案为:2V.