The energy of the capacitor and its capacitance

If two charges are reported to two isolated conductors, a so-called potential difference will arise between them, which depends on the size of these charges and on the geometry of the conductors. In the event that the charges are identical in magnitude but opposite in sign, you can enter the definition of the electrical capacitance, from which you can then derive a notion such as the energy of the capacitor. The electrical capacity 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 the capacitor depends directly on the capacitance. This relationship can be determined by means of calculations. The energy of the condenser (formula) will be represented by a chain:

W = (C * U * U) / 2 = (q * q) / (2 * C) = q * U / 2, where W is the energy of the capacitor, C is the capacitance, U is the potential difference between the two plates (voltage) , Q is the value of the charge value.

The value of the capacitance value depends on the size and shape of the conductor and on the dielectric that separates these conductors. A system in which an electric field is concentrated (localized) only in a certain region is called a condenser. The conductors that make up this device are called the plates. This is the simplest design of the so-called flat capacitor.

The simplest device is two flat plates, which have the ability to conduct electric current. The data of the plates are parallel in a certain (relatively small) distance from each other and separated by a layer of a certain dielectric. The energy of the condenser field in this case will be localized mainly between the plates. However, near the edges of the plates and in some surrounding space, still a weak radiation will emerge. It is called in the literature a scattering field. In most cases, it is accepted to neglect it and assume that the entire energy of the capacitor is located completely between the plates. But in some cases, it is still taken into account (mostly it is the case of using micro-capacitances or, conversely, of super-capacities).

The electrical capacitance (hence the energy of the capacitor) depends directly on the plates. If we look at the formula C = E0 * S / d, where C is the capacitance, E0 is the value of the parameter such as the dielectric constant (in this case, the vacuum) and d is the distance between the plates, it can be concluded that the capacity of such Flat capacitor will be inversely proportional to the value of the distance between these plates and is directly proportional to their area. If the space between the plates is filled with a certain dielectric, the energy of the capacitor and its capacitance will increase by an factor of E (E in this case is the dielectric constant).

Thus, now it is possible to express the formula of potential energy, which accumulates between two plates (plates) of the condenser: W = q * E * d. However, it is much easier to express the notion of "condenser energy" through a capacitance: W = (C * U * U) / 2.

The parallel and serial connection formulas remain valid for any number of capacitors connected to the battery.