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Capacitor Charging

How to Use

  • Voltage / Cap / Res sliders — set the source voltage, capacitance, and series resistance.
  • Charge — start charging animation; voltage rises exponentially toward Vs.
  • Discharge — discharge the capacitor; voltage decays exponentially toward 0.
  • Reset — clear charge and graphs instantly.

What to Observe

  • Voltage \(V_C\) follows \(V_C(t) = V_s(1 - e^{-t/\tau})\) during charging.
  • Current starts high and decays: \(I(t) = \frac{V_s}{R}e^{-t/\tau}\).
  • Stored energy \(E = \frac{1}{2}CV_C^2\) grows with the square of voltage.
  • After one time constant τ = RC, the capacitor reaches ~63% of its final voltage.
  • The three live graphs show V, I, and E simultaneously.

Key Equations

\[\tau = RC\]
\[V_C(t) = V_s\left(1 - e^{-t/\tau}\right) \quad \text{(charging)}\]
\[I(t) = \frac{V_s}{R}e^{-t/\tau}\]
\[E = \frac{1}{2}CV_C^2\]