Calculate how current splits between parallel resistors. Essential for circuit analysis and understanding parallel circuit behavior.
Last updated: March 2026 | By Summacalculator
Current through R₁
6.6667
Amperes (66.7% of total)
Current through R₂
3.3333
Amperes (33.3% of total)
✓ Verification:I₁ + I₂ = 6.6667 + 3.3333 = 10 A (currents sum to total as expected)
Key Insight: Current takes the path of least resistance! R₁ has 100Ω while R₂ has 200Ω, so more current flows through the smaller resistor.
Current division is a fundamental principle in electrical engineering that describes how electrical current splits when it encounters parallel paths in a circuit. When current reaches a junction where the circuit branches into multiple parallel resistors, it divides among the branches inversely proportional to their resistances. Lower resistance paths carry more current, while higher resistance paths carry less.
The current divider rule provides a simple formula to calculate the current through each branch without first finding the voltage across the parallel combination. For two resistors in parallel, the current through resistor 1 equals the total current multiplied by the ratio of resistor 2's resistance to the sum of both resistances: I₁ = IT × (R₂/(R₁ + R₂)). This counterintuitive formula uses the "other" resistor's value because current prefers the lower resistance path.
Current division is the dual principle to voltage division in series circuits. While voltage dividers split voltage in direct proportion to resistances, current dividers split current in inverse proportion. Understanding both principles is essential for analyzing complex circuits, designing proper load distribution, and ensuring components operate within safe current ratings. Current dividers find practical applications in ammeter shunts, LED arrays, and power distribution networks.
Current splits equally: I₁ = I₂ = IT/2. This is the only case where each branch gets an equal share.
Almost all current flows through the smaller resistor: I₁ ≈ IT, I₂ ≈ 0. The larger resistor acts nearly like an open circuit.
If R₂ = 2R₁, then I₁ = ⅔IT and I₂ = ⅓IT. Twice the resistance means half the current.
A 6A current encounters two parallel resistors: 200Ω and 400Ω. How does the current split?
The 200Ω resistor (smaller resistance) carries 4A—twice the current of the 400Ω resistor which carries only 2A. This 2:1 current ratio is the inverse of the 1:2 resistance ratio, demonstrating that current divides inversely proportional to resistance!
The current through a resistor is inversely proportional to its resistance. Using the other resistor's value in the numerator ensures this inverse relationship. Larger resistance means smaller fraction of total current, which the formula captures correctly.
Yes! Current divider is a shortcut. You could calculate equivalent resistance, find voltage across the parallel combination (V = IT × Req), then use Ohm's law (In = V/Rn) for each branch. Current divider saves steps.
For multiple resistors, calculate equivalent resistance of all branches except the one you're analyzing, then use In = IT × (Req/Rn). Alternatively, find the voltage across all resistors and use Ohm's law for each.
Absolutely! KCL states current entering a node equals current leaving. In a current divider, IT = I₁ + I₂ + ... + In. This is why the branch currents always sum back to the total current—it's a fundamental law.
Voltage dividers use series resistors and split voltage in direct proportion to resistance (larger R gets more V). Current dividers use parallel resistors and split current in inverse proportion (larger R gets less I). They're mathematically dual concepts.
Yes, but use impedance (Z) instead of resistance for AC circuits with inductors or capacitors. The same inverse-proportional relationship applies: current preferentially flows through lower impedance paths. Phase angles must also be considered for complex impedances.
Current dividers are used in ammeter shunts (diverting most current around a sensitive meter), LED brightness matching, current sensing, precision current sources, and parallel power supplies. Any time you need controlled current distribution between branches.
All current flows through the remaining path(s). An open circuit has infinite resistance, so its share of current drops to zero. The total resistance increases, which may affect the source's ability to maintain the total current IT.
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