Formula and example
How it is calculated
τ = R × C; U꜀(t) = U × (1 − e^(−t/τ)); I(t) = (U/R) × e^(−t/τ)
Worked example
10 kΩ and 100 µF give τ = 1 s. After 1 s, the capacitor reaches approximately 3.1606 V with a 5 V supply.
Things to check
- After one time constant, the voltage is approximately 63.2% of its final value.
- The capacitor starts uncharged. The source supplies a constant DC voltage.