Parallel Resistor Calculator
Resistors in parallel.
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Energy
Series Resistor Calculator
Find the total resistance of resistors in series.
Total resistance
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In series.
| Resistors used | — |
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Enter your figures above to see the step-by-step working.
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How the Series Resistor Calculator Works
Resistors in series carry the same current, one after another, so their resistances simply add up. Three resistors of 100, 220 and 330 ohms in series total 650 ohms. The total is always larger than any single resistor in the chain.
Series resistors are how you build up a specific value from standard parts, or drop voltage in stages. Combine this with the parallel calculator to work out any resistor network.
Rtotal = R₁ + R₂ + …
Frequently Asked Questions
How do you calculate series resistance?
Just add the resistances together. The total is always larger than any single resistor.
Does current change in series resistors?
No — the same current flows through every resistor in series. The voltage divides among them in proportion to their resistance.
Why put resistors in series?
To reach a value you don’t have as a single part, or to divide voltage across a circuit in steps.
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