If two charges are communicated to two isolated conductors, then between them there will be a so-called potential difference, which depends on the magnitude of these charges and on the geometry of the conductors. In the event that the charges are the same in magnitude, but opposite in sign, you can introduce the definition of electrical capacitance, from which you can then get such a thing as the energy of a capacitor. The electrical capacitance of a system consisting of two conductors is the ratio of one of the charges to the potential difference between these conductors.
The energy of a capacitor directly depends on the capacitance. This ratio can be determined using calculations. The energy of the capacitor (formula) will be represented by the chain:
W=(CUU)/2=(qq)/(2C)=qU/2, where W is the energy of the capacitor, C is the capacitance, U is the potential difference between two plates (voltage), q is the value of the charge.
The value of the electrical capacitance depends on the size and shape of the given conductor and on the dielectric that separates these conductors. A system in which the electric field is concentrated (localized) only in a certain area is called a capacitor. The conductors that make up this device,are called covers. This is the simplest design of the so-called flat capacitor.
The simplest device is two flat plates that have the ability to conduct electricity. These plates are arranged in parallel at a certain (relatively small) distance from each other and are separated by a layer of a certain dielectric. The energy of the capacitor field in this case will be localized mainly between the plates. However, near the edges of the plates and in some surrounding space, rather weak radiation still arises. It is called in the literature the stray field. In most cases, it is customary to neglect it and assume that all the energy of the capacitor is located completely between the plates. But in some cases, it is still taken into account (mainly these are cases of using microcapacities or, conversely, supercapacities).
Electrical capacitance (hence the energy of the capacitor) is directly dependent on the plates. If you look at the formula C \u003d E0S / d, where C is the capacitance, E0 is the value of the value of such a parameter as the permittivity (in this case, vacuum) and d is the value of the distance between the plates, then we can conclude that the capacitance of such flat capacitor will be inversely proportional to the value of the distance between these plates and directly proportional to their area. If the space between the plates is filled with some specific dielectric, then the energy of the capacitor and its capacitance will increase by E times (E inin this case, the permittivity).
Thus, now we can express the formula of the potential energy that accumulates between the two plates (plates) of the capacitor: W=qEd. However, it is much easier to express the concept of "capacitor energy" in terms of capacitance: W=(CUU)/2.
The formulas for parallel and series connection remain true for any number of capacitors connected in a battery.
