§1-5 Network reduction by△- YY transformation R R R R RI b R R R R R+ (R3+R2)(R2+Ra) 1 R3+R+ 3 R+R 2 =R3∥(Rn∥R1+Rn∥R2)§1-5 Network reduction by Δ-Y transformation e d e d ad R R R R R R R R R R + + + + + = + 3 2 3 2 1 ( )( ) //( // // ) ' 2 ' 1 ' Ra d = R3 Ra R + Rd R Ra Rb Rc Re Rd a c b d R1 Re Rd a c d R3 R2 b Ra Rd a b d ' R3 ' R2 ' R1