Current Divider Calculator
Calculate current through two parallel resistor branches.
Current Divider Formula
For two parallel resistors, I1 = It×R2/(R1+R2) and I2 = It×R1/(R1+R2).
How a Current Divider Works
A current divider describes how total current splits between parallel resistor branches. The lower-resistance branch carries more current because both branches share the same voltage while current follows I = V/R.
Example Calculation
If 6 A enters two parallel branches with R1 = 4 Ω and R2 = 8 Ω, the calculator gives I1 = 4 A and I2 = 2 A. The two branch currents add back to the 6 A total.
Factors and Interpretation
Branch current depends on the resistance ratio, not resistance alone. Making R1 smaller increases I1, while increasing R1 sends more of the total current through R2. This two-branch formula assumes ideal parallel resistors connected across the same two nodes.
Frequently Asked Questions
Why is the opposite resistor used in the formula?
The reciprocal relationship comes from parallel branches sharing voltage, so current is inversely proportional to resistance.
Should branch currents add to total current?
Yes. For the two-branch case, I1 + I2 should equal the entered total current.
Can I use this for more than two resistors?
This page is designed for two branches. Larger networks require the conductance form of the current-divider rule.
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Formula and Practical Limits
Current-divider relationships apply to parallel branches and depend on branch impedance. The familiar two-resistor formula assumes resistive DC behavior; AC circuits can require complex impedance rather than resistance alone.