What is Capacitor or Capacitance Definition and Formula

Capacitor or Capacitance: Definition and Formula

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What is capacitor or capacitance? There are three fundamental electrical circuit elements, resistor, inductor and capacitor. The capacitor behaves as a charge storage device in an electrical circuit. It holds the electric charge when we apply a voltage crosswise over, and it surrenders the put away charge to the circuit as when required. Capacitor is a passive electronic component that stores energy in the form of an electrostatic field. In its simplest form, a capacitor consists of two conducting plates separated by an insulating material called the dielectric.

The most basic construction of a capacitor consists of two parallel conductors (usually metallic plates) separated by a dielectric material. When we interface a voltage source over the capacitor, the conductor (capacitor plate) joined to the positive terminal of the source turns out to be emphatically charged, and the conductor (capacitor plate) connected to the negative terminal of the source becomes negatively charged.

What is Capacitor or Capacitance?

Because of the presence of dielectric in between the conductors, ideally, no charge can migrate from one plate to other. In this way, there will be a distinction in charging level between these two conductors (plates).

Hence, an electric potential difference shows up over the plates. The charge collection in the capacitor plates isn’t momentary rather it is step by step evolving. The voltage appears across the capacitor exponentially rises untill it becomes equal to that of the connected voltage source.


Now we understand that the charge accumulation in the conductors (plates) causes the voltage or potential difference over the capacitor. The amount of charge gathered in the capacitor for building up a specific voltage over the capacitor is alluded to as the charge holding limit of the capacitor.

We measure this charge gathering ability of a capacitor in a unit called capacitance. The capacitance is the charge gets stored in a capacitor for developing 1 volt potential difference across it.

See Also: Capacitor in Series and Parallel Voltage Explained

Capacitor (Capacitance) Formula

Hence, there is a direct relationship between the charge and voltage of a capacitor. The charge accumulated in the capacitor is directly proportional to the voltage developed across the capacitor.


Q is the charge and

V is the voltage.

Here C is the constant of proportionality, and this is capacitance.

The capacitance relies on three physical variables, and these are the dynamic zone of the capacitor conductor (plates), the distance between the conductors (plates) and permittivity of the dielectric medium.

See Also: Energy Stored in a Capacitor

Here, ε is permittivity of the dielectric medium, A is the active area of the plate and d is the perpendicular distance between the plates.

The standard unit of capacitance is the farad, abbreviated. This is an expansive unit; progressively normal units are the microfarad, curtailed µF (1 µF =10-6F) and the picofarad, abbreviated pF (1 pF = 10-12 F).

Capacitors can be created onto coordinated circuit (IC) chips. They are regularly utilized related to transistors in powerful irregular access memory (DRAM).

The capacitors help maintain the contents of memory. As a result of their minor physical size, these parts have low capacitance. They must be recharged thousands of times per second or the DRAM will lose its data.

Large capacitors are used in the power supplies of electronic equipment o fall types, including computers and their peripherals. In these systems,the capacitors smooth out the rectified utility AC, providing pure, battery-like DC.

See Also: Working Principle of Capacitor – How a Capacitor Works

Capacitor (Capacitance) Conclusion

After going through the above portion of capacitor (capacitance) explanation we can now establish a capacitor definition. I hope you enjoy when reading this article, thank you.