Series Resistor Calculator
Add resistors in series and see the current and voltage drop across each one.
Step-by-step working
- R = 100 + 220 + 470 = 790 Ω
- I = V / R = 12 / 790 = 0.0152 A
| Resistor (Ω) | Voltage (V) |
|---|---|
| 100 | 1.519 |
| 220 | 3.3418 |
| 470 | 7.1392 |
Mathematical Formula
Overview & Explanation
Series resistors carry the same current; resistances add.
How It Works
- Sum resistances.
- I = V/R.
- Each drop = I × Rᵢ.
Practical Applications
- LED current limiting.
- Voltage ladders.
Example 1: 100 + 220 + 470 Ω at 12 V
Three resistors.
Inputs
Resistances (Ω, comma separated): 100, 220, 470 · Supply voltage (V): 12
Step 1
R = 100 + 220 + 470 = 790 Ω
Step 2
I = V / R = 12 / 790 = 0.0152 A
Total resistance
Result
Example 2: 1k + 2k at 5 V
Two resistors.
Inputs
Resistances (Ω, comma separated): 1000, 2000 · Supply voltage (V): 5
Step 1
R = 1000 + 2000 = 3000 Ω
Step 2
I = V / R = 5 / 3000 = 0.0017 A
Total resistance
Result
How it's calculated & sources
R = Σ Rᵢ; I = V/R; Vᵢ = I Rᵢ.
Frequently Asked Questions
Do drops sum to supply?
Power per resistor?
Tolerance?
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