Home Electrical Engineering Capacitor Charge Calculator

⚡ Capacitor Charge and Time Constant Calculator

Analyze capacitor charging and discharging behavior in RC circuits. Calculate time constants, voltage curves, energy storage, and visualize exponential responses.

Calculation Mode

Circuit Parameters

Interactive RC Circuit

Results & Analysis

Select calculation mode and enter values to see results

Voltage vs Time Curve

Capacitor Fundamentals

A capacitor stores electrical energy in an electric field. When charging through a resistor, the voltage follows an exponential curve governed by the time constant τ = RC.

V(t) = V₀(1 - e^(-t/τ))
Charging: voltage approaches supply voltage exponentially
V(t) = V₀e^(-t/τ)
Discharging: voltage decays exponentially to zero

Time Constant (τ)

The time constant τ = RC determines how quickly a capacitor charges or discharges:

  • 63.2% charged/discharged after 1τ
  • 86.5% charged/discharged after 2τ
  • 95.0% charged/discharged after 3τ
  • 98.2% charged/discharged after 4τ
  • 99.3% charged/discharged after 5τ

Applications

  • Timing Circuits: Delays, oscillators, pulse generators
  • Filtering: Smoothing power supplies, signal conditioning
  • Energy Storage: Flash photography, motor starting
  • Coupling: AC signal transmission, blocking DC
  • Memory: DRAM cells, backup power systems