Series Resistor Calculator

What Is Series Resistance?

Resistors in series share one current path. Each resistor adds to the total opposition to current flow. Series combinations appear in voltage dividers, current-limiting circuits, and LED strings where each element must carry the same current.

Series Resistor Formula

For n resistors in series:

$$R_{total} = R_1 + R_2 + \cdots + R_n$$

Example: 100 Ω and 220 Ω in series give $100 + 220 = 320$ Ω. Total resistance is always greater than any individual resistor.

Practical Uses

Series resistors divide voltage proportionally to resistance. Adding a resistor increases total resistance and reduces current for a fixed supply voltage. Removing one branch breaks the circuit entirely.

Frequently Asked Questions

Why does series resistance increase?

Each resistor adds opposition in the same current path. More resistors in series means more total resistance.

Is current the same through all series resistors?

Yes. Kirchhoff's current law requires the same current through each element in a single series loop.

How do I convert kΩ or MΩ to ohms?

1 kΩ = 1000 Ω and 1 MΩ = 1,000,000 Ω. Enter all values in ohms for consistent results.

What if one resistor is zero ohms?

A zero-ohm resistor acts as a wire. It contributes nothing to total resistance but still completes the path.

How many resistors can I add?

This tool supports up to six series resistors. The same summation formula applies regardless of count.

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What Is Series Resistance?

Series Resistor Formula

Practical Uses

Frequently Asked Questions

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