IB=20µA,IC=5mA,β=250
IB=40µA,IC=5mA,β=125
IB=40µA,IC=10mA,β=250
IB=25µA,IC=5mA,β=200
Vi=VBE+RBiB ———(1)20=500×103×iBiB=40µAVo=VCE−RCiC ———(2)20=4×103iCiC=5mAβ=IC/IB=5mA/40µA=125