单项选择题
图示电路中,变阻器R=200Ω,滑动端C处中点,为使UCB=0.5UAB,则RL应取()
A.50ΩB.∞ΩC.0ΩD.100Ω
A.-50VB.-10VC.10VD.50V
A.2AB.-2AC.2/3AD.-2/3A