How does a DC current differ from a variable and how is it converted?

A constant electric current is the motion of particles with a charge in a certain direction. That is, its voltage or force (characterizing the values) have the same value and direction. This is what a constant current differs from a variable one. But consider everything in order.

The history of the appearance and "war of currents"

The direct current was formerly called galvanic because it was discovered as a result of a galvanic reaction. Thomas Edison tried to transfer it through electric transmission lines. At that time there were serious disputes between scientists on this issue. They even got the name of "war of currents". The question of choice as the main, alternating or permanent was being decided. "Struggle" was won by a variable kind, since the constant carries significant losses, being transmitted at a distance. But to transform a variable kind is easy, this is what a constant current differs from a variable one. Therefore, the latter is easy to transfer even over great distances.

Sources of direct electric current

As sources can serve as batteries or other devices, where it arises through a chemical reaction.

This generators, where it is obtained as a result of electromagnetic induction, and then straightens due to the collector.

Application

In various devices, direct current is used quite often. Many household appliances, chargers and car generators work with it, for example. Any portable device is powered from a source that generates a constant appearance.

On an industrial scale, it is used in engines and batteries. And in some countries they are equipped with high-voltage power lines.

In medicine, with the help of a constant electric current, health procedures are carried out.

On the railway (for transport) both variable and permanent types are used.

Alternating current

Most often, however, apply it is it. Here, the average value of the force and voltage for a certain period is zero. In magnitude and direction, it constantly changes, and with equal intervals of time.

In order to induce an alternating current, generators are used in which an electromotive force arises during electromagnetic induction . This is done by means of a magnet rotated in the cylinder (rotor) and a stator made in the form of a stationary core with a winding.

Alternating current is used in radio, television, telephony and many other systems because its voltage and power can be transformed, almost without losing energy.

Widely used it in industry, as well as for lighting purposes.

It can be single-phase and multiphase.

The alternating current, which varies according to the sinusoidal law, is single-phase. It changes over a certain period of time (period) in magnitude and direction. The AC frequency is the number of periods per second.

In the second case, the most common was a three-phase version. This system of three electric circuits, which have the same frequency and EMF, are shifted in phase by 120 degrees. It is used to power electric motors, furnaces, lighting fixtures.

Many of the developments in the field of electricity and their practical application, as well as the impact on alternating current of high frequency, humanity owes the great scientist Nicola Tesla. Until now, not all of his works, left to descendants, are known.

How does constant current differ from variable and what is its path from source to consumer?

So, a variable is called a current that can vary in direction and magnitude during a certain time. The parameters to which attention is paid are frequency and voltage. In Russia, in household electrical networks, alternating current is supplied, which has a voltage of 220 V and a frequency of 50 Hz. The frequency of an alternating current is the number of changes in the direction of particles of a certain charge per second. It turns out that at 50 Hz it changes its direction fifty times, in which the direct current differs from the variable one.

Its source are sockets, which connect household appliances under different voltages.

Alternating current starts its movement from power plants, where there are powerful generators, from where it comes with a voltage from 220 to 330 kV. Further passes into transformer substations, which are near houses, enterprises and other structures.

In the substation, the current falls under a voltage of 10 kV. There it is converted to a three-phase voltage of 380 V. Sometimes with this indicator the current passes directly to objects (where a powerful production is organized). But basically it is reduced to the usual in all houses 220 V.

Transformation

It is clear that in the sockets we get alternating current. But often for electrical appliances you need a constant view. For this purpose, special rectifiers are used. The process consists of the following:

• Connection of a bridge with four diodes having the necessary power;
• Connection of the filter or condenser to the output from the bridge;
• Connection of voltage regulators to reduce pulsations.

Conversion can occur from either AC to DC or vice versa. But the latter case will be much more difficult to implement. Inverters are required, which, among other things, are quite expensive.