单项选择题

A.Ib=Ec-0.7/R1+R2+(1+β)Rc;Ic=βIb;Uce=Ec-(1+β)IbRc
B.Ib=Ec-0.7/R1-R2+(1+β)Rc;Ic=βIb;Uce=Ec-+1+β)IbRc
C.Ib=Ec+0.7/R1+R2+(1+β)Rc;Ic=βIb;Uce=Ec-(1+β)IeRc
D.Ib=Ec-0.7/R1+R2+(1+β)Rc;Ic=βIb;Uce=Ec-+1+β)IcRc