Anyone who has chosen to work with electrical engineering as a profession, should very well understand what are the sources of supply, as well as their characteristics and differences.In fact, nothing complicated, as we will show in this article.
difficult to imagine how the world would look modern, it disappear from the electrical energy and related appliances.Perhaps mankind still would use steam engines and the muscle power of animals and of their own brethren.One can not say exactly who first discovered electricity, Thus, spinners in ancient Syria used the properties of amber magnetized (electrified), Aristotle tried to explore the possibilities of electric ray, well aware of the danger of lightning from the beginning of the world (no wonder some peoples worshiped it).
Electric current comes in two varieties - AC and DC.This difference is due to the way it is received.Accordingly, the AC power current issue of the first type, and DC - the second.By the way, here the division into "first - second 'probation.In electrical engineering it is used as a source of AC power and DC.Let us recall some theory.
Any electric current is the motion of charged particles directed by conductive material electromotive force EMF.External effects reported by some electrons at the outer orbits of atoms, more sufficient energy to overcome the attraction of the nucleus.The result is the free charge carriers - electrons and ions.According to the law of conservation of energy, a process of natural recombination of particles from the surrounding atoms in the lattice.Without forcing the structure of the material is restored.However, if the source is connected to the conductor EMF generated by the recombination of field directs them in the right direction - an electric current.AC power is actually a generator emf vector orientation is periodically reversed.Hence the name "variable."AC power supply in most cases represented generating capacity - generators in modern power plants produce exactly alternating current.They are more reliable in operation and easy to maintain, than the collector model DC.The diagrams AC power are often designated by a circle with a wave inside.This wave - a symbolic image of a sine wave.
Source AC creates a movement of the particles not only change the direction, but also a "floating" the current value.Sine itself indicates that periodically passes through zero value.
It is based on a different principle, DC sources.They create a constant in the conductor in the direction of the electric field that forms the directional movement of the particles have a charge.It is considered that the current flows from positive to the negative contact (from positive to negative).In reality, the motion of electrons occurs in the opposite direction - from minus to plus.Since the charge of a single electron is negative, the pole with a "minus" sign indicates a surplus of these particles (hence the total charge).Based on the fact that the oppositely charged particles are mutually attracted, it is not difficult to guess that the electrons move through a wire from "minus" to "plus".Allowed artificial change of the current value - from the current does not cease to be a constant.There are many different solutions to convert the direct current into alternating (sine wave generator) and vice versa (rectifiers, bridges).
