100, 220 and 330 Ω
- Input
- ser 100 220 330
- Expected output
- 650
Direct sum: 650 Ω.
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series resistor calculator
In series, resistors form a single path and the total resistance is the sum. More interesting than the sum is what happens to the voltage: it splits among the parts in proportion to value. The tool opens with 100, 220, 330 and 470 Ω on 12 V and shows, for each resistor, the voltage across it, the current and the power it dissipates.
Direct sum: 650 Ω.
7,900 Ω; larger than the largest resistor.
12 V gives 10.71 mA.
Double one.
3 × 47 = 141 Ω.
Adds 1% to the main value.
Add the inverses and invert the result: R = 1 ÷ (1 ÷ R1 + 1 ÷ R2 + ...). For two, R = R1 × R2 ÷ (R1 + R2). Example: 220 Ω and 330 Ω give 132 Ω. The result is always smaller than the smallest resistor.
Add the values: R = R1 + R2 + ... + Rn. For 100, 220 and 330 Ω, the total is 650 Ω. The result is always larger than the largest resistor.
In proportion to value: V = I × R in each. At 12 V, with 100, 220, 330 and 470 Ω, the voltages are 1.07, 2.36, 3.54 and 5.04 V, which add up to the supply's 12 V.
Yes. There is no other path, so the same current flows through all of them. That is why the largest-value part has the biggest voltage drop and dissipates the most power.
To get a value that does not exist in the standard series, to fine-tune a value, to divide voltage in a divider and to share power among smaller parts, which together can handle more.
| R | Voltage | Current | Power |
|---|---|---|---|
| 100 Ω | 1.07 V | 10.7 mA | 11.5 mW |
| 220 Ω | 2.36 V | 10.7 mA | 25.3 mW |
| 330 Ω | 3.54 V | 10.7 mA | 37.9 mW |
| 470 Ω | 5.04 V | 10.7 mA | 54 mW |
| R | Voltage | Current | Power |
|---|---|---|---|
| 100 Ω | 12 V | 120 mA | 1.44 W |
| 220 Ω | 12 V | 54.5 mA | 655 mW |
| 330 Ω | 12 V | 36.4 mA | 436 mW |
| 470 Ω | 12 V | 25.5 mA | 306 mW |
The math runs in your browser; no value is sent to a server. Combinations use nominal values: resistor tolerance adds on top of the error shown.