Capacitance Calculator

Calculate capacitance for parallel plate capacitors, series and parallel capacitor combinations, and convert between different capacitance units.

Calculator Input

Enter values and click Calculate to see results

About Capacitance and Capacitors

What is Capacitance?

Capacitance is a measure of a capacitor's ability to store electric charge. The basic unit of capacitance is the farad (F), named after physicist Michael Faraday. A capacitor has a capacitance of one farad when a charge of one coulomb results in a potential difference of one volt across its terminals.

In practical electronic circuits, capacitors typically have much smaller values, measured in microfarads (μF), nanofarads (nF), or picofarads (pF). The capacitance value depends on the physical characteristics of the capacitor, such as the area of the plates, the distance between them, and the dielectric material between the plates.

Capacitors are fundamental components in electronic circuits, serving various functions including energy storage, signal coupling and decoupling, filtering, timing, and tuning.

What is Capacitance?

Capacitors are fundamental components in electronic circuits, serving various functions including energy storage, signal coupling and decoupling, filtering, timing, and tuning.

How to Use This Calculator

This calculator offers multiple functions to help you with capacitance calculations:

Choose the calculation mode from the tabs: Parallel Capacitors, Series Capacitors, Unit Conversion, or Parallel Plate Capacitor (default).
For parallel or series calculations, enter the capacitance values for each capacitor and add more capacitors if needed.
For unit conversion, enter a value and select the source and target units.
For parallel plate capacitor calculations, select the dielectric material, plate area, and separation distance.
Click the Calculate button to see the results.

The results include a visualization to help you understand the relationship between the values.

Capacitance Formulas

The following formulas are used for calculating capacitance in different scenarios:

Parallel Plate Capacitor Formula

$$C = \arepsilon_0 \ imes \arepsilon_r \ imes \rac{A}{d}$$

Where: - C is the capacitance in farads (F) - ε₀ is the vacuum permittivity (8.85 × 10⁻¹² F/m) - εᵣ is the relative permittivity of the dielectric material - A is the area of plate overlap in square meters - d is the separation between plates in meters

Parallel Capacitors Formula

$$C_{total} = C_1 + C_2 + C_3 + ... + C_n$$

Where: - Cₜₒₜₐₗ is the total capacitance - C₁, C₂, C₃, etc. are the individual capacitances In a parallel configuration, the total capacitance is the sum of all individual capacitances.

Series Capacitors Formula

$$\rac{1}{C_{total}} = \rac{1}{C_1} + \rac{1}{C_2} + \rac{1}{C_3} + ... + \rac{1}{C_n}$$

Where: - Cₜₒₜₐₗ is the total capacitance - C₁, C₂, C₃, etc. are the individual capacitances In a series configuration, the reciprocal of the total capacitance is the sum of the reciprocals of all individual capacitances. This means the total capacitance is always less than the smallest individual capacitance.

Energy Storage Formula

$$E = \rac{1}{2} \ imes C \ imes V^2$$

Where: - E is the energy stored in joules (J) - C is the capacitance in farads (F) - V is the voltage across the capacitor in volts (V)

Capacitance Unit Conversion

1 F (法拉) = 1,000,000 μF (微法拉)
1 μF (微法拉) = 1,000 nF (纳法拉)
1 nF (纳法拉) = 1,000 pF (皮法拉)

Capacitance units are related by factors of 1000: - 1 farad (F) = 1,000,000 microfarads (μF) - 1 microfarad (μF) = 1,000 nanofarads (nF) - 1 nanofarad (nF) = 1,000 picofarads (pF)

Capacitor Applications

Capacitors are essential components in electronic circuits and have numerous applications:

Filtering

Capacitors can filter out unwanted frequencies in electronic circuits. They are commonly used in power supplies to smooth out ripples and in audio circuits to filter out noise.

Coupling and Decoupling

Capacitors can pass AC signals while blocking DC, making them useful for coupling signals between circuit stages. They are also used for decoupling (bypassing) to provide a low-impedance path for AC signals.

Tuning Circuits

Variable capacitors are used in tuning circuits, such as in radio receivers, to select specific frequencies.

Energy Storage

Capacitors can store electrical energy for later use. Supercapacitors can store large amounts of energy and are used in applications requiring quick bursts of power.

Common Dielectric Materials

Material	Relative Permittivity (εᵣ)	Common Applications
Vacuum	1.0	Reference standard
Air	1.0006	Variable capacitors, trimmer capacitors
Paper	3.5	Low-cost capacitors, older electronics
Glass	7.5	High-voltage applications
Ceramic	6.0	Bypass and coupling capacitors, temperature-stable applications

Frequently Asked Questions

What is the difference between series and parallel capacitor configurations?

In a parallel configuration, the total capacitance is the sum of all individual capacitances. In a series configuration, the reciprocal of the total capacitance is the sum of the reciprocals of all individual capacitances, resulting in a total capacitance that is less than the smallest individual capacitance.

Why does the dielectric material affect capacitance?

The dielectric material between capacitor plates increases the capacitance by reducing the electric field strength. The relative permittivity (εᵣ) of the material determines how much the capacitance increases compared to a vacuum.

What are the common units for capacitance?

The SI unit for capacitance is the farad (F). However, this is a very large unit for practical electronics, so microfarads (μF, 10⁻⁶ F), nanofarads (nF, 10⁻⁹ F), and picofarads (pF, 10⁻¹² F) are more commonly used.

How do temperature and frequency affect capacitance?

Both temperature and frequency can affect capacitance, depending on the capacitor type. Ceramic capacitors can be particularly sensitive to temperature changes. Some capacitors also show frequency-dependent behavior due to dielectric absorption and other factors.

What is ESR in capacitors?

ESR (Equivalent Series Resistance) is the internal resistance of a capacitor that appears in series with the ideal capacitance. Lower ESR is generally better, especially in power supply filtering applications, as it reduces power loss and improves filtering performance.

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