The RC time constant sets the exponential charging or discharging timescale.
Difficulty
Intermediate
Read time
5 min
Prerequisites
Basic algebra and consistent SI units
Source
OpenStax, College Physics 2e, §21.6 (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.
The RC time constant sets the exponential charging or discharging timescale. After one time constant, about 36.8% of an initial deviation from the final voltage remains, so about 63.2% of the change is complete.
| Symbol | Meaning | Units |
|---|---|---|
| RC time constant | ||
| Resistance seen by the capacitor | ||
| Capacitance |
Estimate capacitor response times.
Set the timescale of an exponential voltage decay.
A first-order RC circuit has R = 1000 Ω and C = 1.00 µF. Find its time constant.
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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