A charged capacitor stores energy in its electric field.
Difficulty
Beginner
Read time
5 min
Prerequisites
Basic algebra and consistent SI units
Source
OpenStax, College Physics 2e, §19.7 (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. The textbook section link was corrected.
A charged capacitor stores energy in its electric field. For a fixed capacitance, doubling the voltage multiplies stored energy by four. This expression gives stored energy, not the energy lost in a charging resistor.
| Symbol | Meaning | Units |
|---|---|---|
| Stored electric-field energy | ||
| Capacitance | ||
| Voltage across the capacitor |
Estimate stored energy in a charged capacitor.
Compare energy at different capacitor voltages.
An ideal 20.0 µF capacitor has 100 V across it. Find its stored energy.
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. The textbook section link was corrected.
Assumptions
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