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Resistors in series
Beginner
Resistances add.
R = R₁+R₂The same current flows through each, voltages add, and R = R₁ + R₂ + ... The largest resistor gets the largest voltage.
10 Ω + 20 Ω = 30 Ω.
One break stops the entire circuit.
In more detail
In series, resistors share the same current, and their resistances add, R = R1 + R2 + ... The total resistance is larger than any individual resistor.
Real-world uses
- Christmas lights in series share current through each bulb.
- Voltage dividers use series resistors to share voltage.
- Electricians combine resistors in series to create a specific value when a single resistor is not available.
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Frequently asked questions
Why does adding resistors increase resistance?
Because the current must pass through each resistor one after another.
What happens if one bulb fails in series?
The whole circuit stops, since the current path is broken.
What happens to the current in series resistors?
It is the same through each resistor, so the voltage divides across them in proportion to their resistances.
Related topics in Current Electricity & Circuits
Temperature dependence of resistance · Superconductors · Semiconductors and thermistors · Resistors in parallel · Colour code of resistors · Electric power