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⏱️ RC Time Constant Calculator

Calculate RC time constants, analyze capacitor charging/discharging behavior, and design RC timing circuits with precise calculations.

Calculation Type

Input Parameters

RC Time Constant
τ = R × C
Calculate time constant from resistance and capacitance

Results & Analysis

Enter values and click Calculate to see RC circuit analysis results

RC Circuit Theory

Time Constant (τ)

The time constant determines how fast a capacitor charges or discharges through a resistor.

  • τ = R × C (seconds)
  • 63.2% charge/discharge in 1τ
  • 95% charge/discharge in 3τ
  • 99.3% charge/discharge in 5τ

Charging Equation

Capacitor voltage increases exponentially toward the supply voltage.

  • Vc(t) = V₀(1 - e^(-t/τ))
  • Ic(t) = (V₀/R) × e^(-t/τ)
  • Initial current = V₀/R
  • Final voltage = V₀

Applications

  • Timing Circuits: Delays and pulse generation
  • Filters: Low-pass and high-pass filters
  • Power Supplies: Smoothing and regulation
  • Oscillators: Relaxation oscillators