ELECTRICAL / CALCULATOR
RC Time Constant
Convert resistance and capacitance units and review capacitor charging and discharging times.
Input Parameters
Edit the example values. Results update as you type.
Results
- RC Time Constant
- 1s
Formula
τ = R × CSubstitution
τ = 10,000 Ω × 0.0001 F = 1 sCalculation Steps
- Convert resistance to Ω and capacitance to F.
- Multiply them to obtain the time constant. The table describes ideal first-order charging and discharging.
Result Explanation
1τ, 3τ and 5τ mean one, three and five time constants. Rise percentages refer to the full step change.
| Multiple | Time (s) | Rise Toward Final Value | Remaining After Decay |
|---|---|---|---|
| 1τ | 1 | 63.21% | 36.79% |
| 3τ | 3 | 95.02% | 4.98% |
| 5τ | 5 | 99.33% | 0.674% |
Formulas and FAQ
τ = R × CWhat is the capacitor state after 5τ?
An ideal first-order charge reaches about 99.3% of the total change. Discharge leaves about 0.7% of the initial deviation.