Current Divider
I1 = Itotal × R2 / (R1 + R2)
Quick answer
This calculator solves I1 = Itotal × R2 / (R1 + R2) for Branch Current. With Total Current 4.4 A, R1 0.47 kΩ, R2 1.03 kΩ, the result is 3.021 A. It solves in 4 directions, so you can enter the values you have and get the one you need.
Calculator
Formula
Description
The current divider rule describes how current splits between parallel branches inversely proportional to their resistance. A branch with lower resistance carries more current, while a branch with higher resistance carries less. This is the dual of the voltage divider and follows directly from the fact that parallel branches share the same voltage. Notice the counterintuitive cross-relationship: the current through R1 depends on R2, not R1, because the shared voltage is set by the parallel combination.
Variables
- Itotal — Total current entering the parallel network (A)
- R1 — Resistance of branch 1 (Ω)
- R2 — Resistance of branch 2 (Ω)
- I1 — Current through R1 (A)
Practical Notes
For more than two parallel branches, use I_k = Itotal × (Rtotal / Rk) where Rtotal is the parallel combination of all branches. Current dividers are fundamental to understanding transistor biasing and current mirror circuits.
Symbols and units
| Symbol | Meaning | Default unit | Accepted units |
|---|---|---|---|
| I1 | Branch Current | A | pA, nA, µA, mA, A, kA |
| Itotal | Total Current | A | pA, nA, µA, mA, A, kA |
| R1 | R1 | Ω | mΩ, Ω, kΩ, MΩ |
| R2 | R2 | Ω | mΩ, Ω, kΩ, MΩ |
Step by step
- 1. What you know: Total Current 4.4 A, R1 0.47 kΩ, R2 1.03 kΩ
- 2. The relation: I1 = Itotal × R2 / (R1 + R2)
- 3. Substitute: Itotal = 4.4 A, R1 = 0.47 kΩ, R2 = 1.03 kΩ
- 4. Result: Branch Current = 3.021 A
Related quantities from the same inputs
- P = I² × R = 9.099 kW
Worked examples
Minimum range
Given: Total Current 4.4 mA, R1 1 Ω, R2 2.2 Ω
Result: Branch Current = 3.025 mA
Low range
Given: Total Current 44 mA, R1 10 Ω, R2 22 Ω
Result: Branch Current = 30.25 mA
Typical
Given: Total Current 4.4 A, R1 0.47 kΩ, R2 1.03 kΩ
Result: Branch Current = 3.021 A
High range
Given: Total Current 0.22 kA, R1 4.7 kΩ, R2 10.3 kΩ
Result: Branch Current = 151.1 A
Maximum range
Given: Total Current 2.2 kA, R1 47 kΩ, R2 103 kΩ
Result: Branch Current = 1.511 kA
Solving for each variable
Solve for Branch Current
Total Current 4.4 mA, R1 1 Ω, R2 2.2 Ω → 3.025 mA
Solve for Total Current
Branch Current 2 mA, R1 1 Ω, R2 2.2 Ω → 2.909 mA
Solve for R1
Branch Current 2 mA, Total Current 4.4 mA, R2 2.2 Ω → 2.64 Ω
Solve for R2
Branch Current 2 mA, Total Current 4.4 mA, R1 1 Ω → 0.8333 Ω
How Branch Current changes with Total Current
| Total Current (input) | Branch Current (result) |
|---|---|
| 0.968 A | 0.6659 A |
| 2.42 A | 1.665 A |
| 4.84 A | 3.329 A |
| 7.26 A | 4.994 A |
| 9.68 A | 6.659 A |
| 14.52 A | 9.988 A |
| 19.36 A | 13.32 A |
| 38.72 A | 26.63 A |
| 67.76 A | 46.61 A |
| 96.8 A | 66.59 A |
The same result in other units
| Unit | Value |
|---|---|
| µA | 3021000 |
| mA | 3021 |
| A | 3.021 |
| kA | 0.003021 |
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<p><a href="https://vbatpower.com/formulas/current-divider/">Current Divider</a> Calculator by vbatpower.com</p>Frequently asked questions
How do you calculate Current Divider?
Use I1 = Itotal × R2 / (R1 + R2). With Total Current 4.4 A, R1 0.47 kΩ, R2 1.03 kΩ, Branch Current works out to 3.021 A.
What is the formula for Current Divider?
The formula is I1 = Itotal × R2 / (R1 + R2). The current divider rule describes how current splits between parallel branches inversely proportional to their resistance.
How do you find Total Current when you know the other values?
Rearrange for Total Current: with Branch Current 2 mA, R1 1 Ω, R2 2.2 Ω, Total Current is 2.909 mA.
How do you find R1 when you know the other values?
Rearrange for R1: with Branch Current 2 mA, Total Current 4.4 mA, R2 2.2 Ω, R1 is 2.64 Ω.
What units does Current Divider use?
Branch Current is shown in µA, mA, A, kA. Values are held in SI base units internally, so you can mix prefixes without converting by hand.
Related Concepts
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