Parallel resistors have the same voltage across them and their currents add.
Difficulty
Beginner
Read time
5 min
Prerequisites
Basic algebra and consistent SI units
Source
OpenStax, College Physics 2e, §21.1 (Paul Peter Urone and Roger Hinrichs)Textbook reference retained from the OpenFormulaGraph dataset; adaptation credits and license are provided below.
Adapted from OpenFormulaGraph, under CC BY 4.0.
FormuLab adapted the notation, explanations, assumptions, and topic placement, and expanded the numerical check into a worked example.
Parallel resistors have the same voltage across them and their currents add. The equivalent resistance of two positive resistors is less than either individual resistance because the network provides another current path.
| Symbol | Meaning | Units |
|---|---|---|
| Equivalent parallel resistance | ||
| First resistance | ||
| Second resistance |
Simplify parallel branches.
Compare a network before and after adding a branch.
Two ideal 4.00 Ω resistors are connected in parallel. Find their equivalent resistance.
Textbook reference retained from the OpenFormulaGraph dataset; adaptation credits and license are provided below.
Adapted from OpenFormulaGraph, under CC BY 4.0.
FormuLab adapted the notation, explanations, assumptions, and topic placement, and expanded the numerical check into a worked example.
Assumptions
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