Current Divider Calculator

What is a Current Divider?

A current divider is a circuit configuration where two or more resistors are connected in parallel across a current source. The total input current (Iin) splits between the parallel branches in inverse proportion to their resistances — more current flows through the lower-resistance path.

This is the dual of the voltage divider. Where a voltage divider uses series resistors to split voltage, a current divider uses parallel resistors to split current.

Current Divider Formulas

• I1 = Iin × R2 ÷ (R1 + R2) — current through R1.
• I2 = Iin × R1 ÷ (R1 + R2) — current through R2.
• Rp = (R1 × R2) ÷ (R1 + R2) — equivalent parallel resistance.

Note that I1 is determined by R2 (not R1) — this is because a larger R2 means less parallel path, which forces more current through R1.

Practical Applications

Current dividers appear in sensor bias circuits, transistor emitter networks, and precision measurement systems. The parallel resistance formula is also essential when calculating the total resistance of any parallel resistor combination, commonly encountered in PCB design and circuit analysis.