Capacitor Size Calculator


About Capacitor Size Calculator (Formula)

The Capacitor Size Calculator is an electrical engineering tool used to determine the appropriate capacitance value for a capacitor in an electronic circuit. It’s essential for designing circuits that require specific timing, filtering, or energy storage functions.

The formula for calculating capacitor size involves considering factors like desired time constant, circuit frequency, and load resistance.

The formula for capacitor size is:

Capacitance (C) = Time Constant (τ) / (Resistance (R) × 2π)


  • Capacitance (C) is the desired capacitance value of the capacitor, typically measured in farads (F).
  • Time Constant (τ) is the desired time constant of the circuit, indicating how quickly the capacitor charges and discharges. It is typically measured in seconds (s).
  • Resistance (R) is the load resistance or impedance of the circuit, typically measured in ohms (Ω).
  • π (pi) is a mathematical constant approximately equal to 3.14159.

The Capacitor Size Calculator is crucial for selecting the appropriate capacitor to achieve specific circuit performance goals, such as filtering out certain frequencies, stabilizing voltage levels, or controlling the timing of events.

Using the calculator, electrical engineers and designers can ensure that circuits function as intended, meet design specifications, and optimize performance.

It’s important to note that the formula assumes idealized conditions and does not account for factors like capacitor tolerance, voltage ratings, and non-ideal behavior at high frequencies.

Leave a Comment