Capacitor Size Calculator

Capacitor Size Calculator:

Enter the values of energy, E_(J), and voltage, V_(V), to determine the value of Capacitor Size, C_(F).

Enter Energy:		J
Enter Voltage:		V
Result – Capacitor Size:		F

Capacitor Size :

Capacitor size refers to the amount of electric charge a capacitor can store per volt of potential difference across its plates. It is measured in farads (F), but for practical applications, microfarads (µF), nanofarads (nF), or picofarads (pF) are often used.

Capacitors are critical in electrical and electronic circuits, including power factor correction, energy storage, filtering, and motor start applications.

In power systems, especially in motors, capacitor sizing ensures the circuit runs efficiently and within safe voltage limits.A properly sized capacitor improves the power factor, reducing energy losses and overall electricity costs.

Undersized capacitors may not provide sufficient reactive power support, while oversized capacitors may cause overvoltage issues or resonance.Capacitor energy storage depends on the voltage applied and its capacitance value.
The energy (E) stored in a capacitor is given in joules (J) and depends on the capacitance and the voltage across it.

The energy is proportional to the square of the voltage and directly proportional to the capacitance.Therefore, an increase in either the voltage or capacitance results in greater energy storage.

Capacitor selection for circuits should consider voltage rating, capacitance, operating temperature, and tolerance.In AC systems, capacitor banks are used for power factor correction by supplying leading reactive power.
In DC applications, capacitors act as energy reservoirs or filters.To calculate the size of a capacitor needed to store a specific amount of energy at a given voltage, a standard energy-capacitance relationship is used.

Capacitor Size, C_(F) in farads equals energy, E_(J) in joules, divided by 0.5 multiplied by the square of voltage, V_(V) in volts.

Capacitor Size, C_(F)= E_(J)/ 0.5 * V²_(V)

C_(F)= capacitor size in Farads, F.

E_(J)= energy in Joules, J.

V_(V)= voltage in volts, V.

Capacitor Size Calculation:

1. Given: E_(J)= 6J, V_(V)= 12V.

Capacitor Size, C_(F)= E_(J)/ 0.5 * V²_(V)

C_(F)= 6 / 0.5 * 12²

C_(F)= 6 / 72

C_(F)= 0.0833F.

2. Given: C_(F)= 0.1F, V_(V)= 10V.

Capacitor Size, C_(F)= E_(J)/ 0.5 * V²_(V)

E_(J)= C_(F)* 0.5 * V²_(V)

E_(J)= 0.1 * 0.5 * 10²

E_(J)= 0.5 * 10

E_(J)= 5J.