Next, we apply
Kirchhoff’s loop rule to closed loops ADBA and CBDC The first
loop gives
–I1 R1 + 0 + I2 R2 = 0        (Ig = 0)  
(3 62)
and the second loop gives, upon using I3 = I1, I4 = I2
I2 R4 + 0 – I1 R3 = 0        
(3 63)
From Eq