I=ViR2+R1 Vo=IR2=ViR2R2+R1 VoVi=R2R2+R1 VoVi=R2R2+R1
V=V2R1R1+R3=V1R1R2+R1 V2V1=R1+R3R1R1R2+R3 V2V1=R1+R3R2+R3 V2V1=R1+R3R2+R3
R1=RaRbRa+Rb+Rc R2=RbRcRa+Rb+Rc R3=RcRaRa+Rb+Rc