Perhatikan diagram berikut ini.

1/R paralel = 1/2 + 1/2
1/r = 2/2
r = 1 ohm
R total = 1 ohm + 3 ohm
= 4 ohm

I = v/r total
I = 12/4
I = 3 A

I1 = v/R1.
= 12/2
= 6 A

I2= v/R2
= 12/2
= 6A

I3 = v/R3
= 12/3
= 4 A