U1U126 8 Ui RI R2+ r3 243 1 2= R3= Ur R2+R3 137 所以 Zu= Ui 26 I2=0 Z2 U2 7262613 I2=08 1 1 1 2 3 1 11 1 U 7 26 31 41 U 21U R R U RU I       = + = + + = + 1 1 3 2 3 1 2 U 74 31 31 41 U R R R U U      = + = + = Ω 132 Ω 4 267 74 Ω 2 2 1 = =  = = = = == 26 IU 267 I Z U1 I 0 11 I 0 1 1 22   Z 所以