Operation of electric current: general characteristic, formula, practical value

From the physics course it is known that one of the characteristics of any body is its ability to do work, since the latter represents nothing more than the transformation of one type of energy into another (for example, the potential one into the kinetic one). In this case it is necessary to take into account the famous law of conservation of energy, formulated as early as the 18th century by M.V. Lomonosov, according to which energy never disappears, it only changes, takes a different form. All of the above is equally applicable not only to solid bodies, but also to other types of matter, including electric current.

Electric current, as has long been proven, is the directed motion of charged particles. Moving along a certain section of the chain, these particles form an electric field that does the work. The work of an electric current is that amount of energy that must be expended in order to transfer a charge over a given electrical circuit. At the same time, not all current work is useful and effective. A fairly appreciable part of the energy is expended in order that the electric charge overcome the resistance of elementary particles in the conductor and in the source of the chain.

The work of an electric current, the formula of which, as follows from the above text, A = U • Q, is the most important characteristic of this special kind of matter. In this formula, U is the potential difference (voltage) in the circuit section, and Q is the quantitative expression of the charge carried over the section.

However, the work of the electric current alone would not be of particular interest if the regularity connecting this work and the amount of thermal energy allocated in this case were not found . This regularity was discovered almost simultaneously by two well-known physicists - Lenz and Jodie Prescott, and therefore the law in the scientific community was called the "Law of Joule-Lenz". According to this law, it turns out that the amount (or power) of heat that is released in a certain volume when charged particles flow through it is directly dependent on the product of the field strength on the density of the current flowing through this section. This law is of great importance for calculating the losses of electricity when it is transmitted over long-distance wires.

The work of an electric current is directly related to another most important quantity-power. The current capacity in physics is understood as the quantitative characteristic of the conversion and the transmission rate of electric energy. Power is measured in kilowatt-hours, while the work of electric current is in joules.

To obtain the maximum current power from a particular source, it is necessary to take into account the characteristics of this source, and also that the resistances of the internal and external circuits must be comparable with each other, otherwise all the work done will go to overcome the difference in resistances.

The operation of an electric current is an important physical characteristic that must be taken into account in virtually all industries, as well as in the production and transmission of energy over considerable distances.