The current divider principle states that in a parallel circuit, the total current divides up among the branches proportionally to the resistances of each branch. Specifically: I1 = IT * R2 / (R1 + R2) I2 = IT * R1 / (R1 + R2) Where IT is the total current, I1 and I2 are the currents in each branch, and R1 and R2 are the resistances of each branch. This allows simplifying some Ohm's law calculations for parallel circuits with two branches. The principle is only applicable when there are two parallel branches.

1. Current Divider Principle
In parallel circuits the current IT divides up through the
various branch networks, I1, I2.
The ratio between any two branch currents is the inverse
ratio of the branch resistances.
I1 = IT
R2
R1 + R2
E
+
-
IT
R2R1
I1 I2
IT
I2 = IT
R1
R1 + R2
This procedure is only suitable where there are two parallel
branches.

2. Current Divider Principle
When there are only two resistances in parallel we can simplify some of the
Ohm’s law calculation by use of the current divider principle.
The current divider uses the principles of Ohm’s law to generate the branch
currents I1 and I2.
This procedure is only suitable where there are two parallel branches.
E
+
-
IT
R2R1
I1 I2
IT
I1 = IT
R2
R1 + R2
Reff
E
IT =
I2 = IT
R1
R1 + R2

3. Divider Networks
Activity
1. For the network shown, use the current divider principle to evaluate the
branch currents if RLOAD is 1000Ω.
2. If the load resistance (RLOAD ) is reduced to 500Ω what current will flow in
each branch assuming the source current stays the same at 2A.
3. Comment on your results.
What is the effect on the branch currents supplied by the 2A current source as
the load (RLOAD )varies.
IT
RLOAD
ILOADI1
R1
150Ω
R2
250Ω
+
-
2AIT