RC charge curve calculator

Inspect ideal capacitor charging or discharging, with τ, target time and an actual calculated curve.

Your input

Outputs are cleared when the input changes.

Result

Enter your data or use the example, then run the tool.

Worked example

1,000 Ω and 100 µF give τ=0.1 s. At τ, charging reaches about 63.212%.

Discharging leaves about 36.788% at τ; exactly 0% remaining is approached asymptotically.

Method

Convert µF to F and compute τ=RC. Charging uses −expm1(−t/τ), discharge uses exp(−t/τ).

Target time uses the appropriate logarithm; curve points span zero to five time constants.

Limits

R and C must be positive; target fraction 0–1. Exact full charge or zero discharge has no finite time.

No leakage, ESR, tolerance, high-voltage wiring or safe-discharge assessment. Floating-point model only.

Sources

OpenStax: RC circuits

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