Electricity & Magnetism
Resistors in Series
Total resistance of resistors in series.
Variables
ReqΩ
Equivalent resistance
Total resistance
In SI units: kg·m²/(A²·s³)
Allowed values: 0 or more
R₁Ω
Resistance 1
First resistor
In SI units: kg·m²/(A²·s³)
Allowed values: 0 or more
R₂Ω
Resistance 2
Second resistor
In SI units: kg·m²/(A²·s³)
Allowed values: 0 or more
Derivation
Same current: V = V₁ + V₂ = IR₁ + IR₂ = I(R₁ + R₂).
Your notes
0/5000
Check value
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- R₁ = 2 Ω (Resistance 1)
- R₂ = 3 Ω (Resistance 2)
Result: Req = 5 Ω
Where this formula is listed
- Electricity & Magnetism formulas, under Electric Circuits, alongside Electric Power, Electric Current, Resistance, Kirchhoff's Voltage Law and Kirchhoff's Current Law.
- In the electricity & magnetism list it comes after Resistance and before Resistors in Parallel.
- Electricity & Magnetism formula sheet, one of 48 formulas printed with symbol keys and SI units.
- The full formula index, grouped by category and topic.
Common questions
What is the Resistors in Series formula?
Resistors in Series is written R_eq = R₁ + R₂ + R₃ + ... Total resistance of resistors in series. It belongs to Electricity & Magnetism, under Electric Circuits.
What are the units in R_eq = R₁ + R₂ + R₃ + ...?
In SI units, R_e q is equivalent resistance, measured in kg·m²/(A²·s³); R₁ is resistance 1, measured in kg·m²/(A²·s³); R₂ is resistance 2, measured in kg·m²/(A²·s³).
How is the Resistors in Series formula derived?
Same current: V = V₁ + V₂ = IR₁ + IR₂ = I(R₁ + R₂). The result is R_eq = R₁ + R₂ + R₃ + ...