# Alternating current and direct current, characteristics and applications!

It is practically impossible to imagine the world without electricity, isn’t it? Electric appliances, electronics, residential, industrial installations, transmission lines and many other things require electric power, whether it is direct or alternating current!

The electric current can be of the direct current or alternating current type. Do you know what is the difference between direct current and alternating current? The World of Electrical has made this article explaining what electrical current is, presenting the characteristics of direct current, alternating current and showing the main differences between them. So come on guys!

What is the electric current?
We can define electrical current as the ordered movement of electrons in a given conductive material. The electric current appears only when there is a difference in electric potential between two points, that is, there is only an electric current when there is an electric voltage.

The electric current is nothing more than the way to balance the electric charges between the two points, because the electrons will pass from the less positive potential where there is an excess of electrons, to the more positive potential, where there is a lack of electrons.

The conventional and real sense of electrons
When we speak of electric current we can speak of the real and the conventional sense. When performing the analysis of electrical circuits we assume that the electrical current leaves the most positive potential for the lowest potential, this being the conventional direction of the electrical current.

As its name suggests, the real sense of the electric current is nothing more than the real sense of the electric current, where the current goes from the smallest electrical potential to the largest electrical potential.

Direct current X Alternating current

Como mencionamos anteriormente, existe tanto a corrente contínua quanto a corrente alternada e quando nos referimos a tensão constante ao longo do tempo, isto é, não varia a sua polaridade no tempo, estamos falando de um sinal em corrente contínua. Porém quando falamos em um sinal de tensão que varia ao longo do tempo, ou seja, varia a sua polaridade no tempo, é considerado uma corrente alternada.

O que é corrente alternada (CA)?
A corrente alternada apresenta como principal característica não possuir uma polaridade bem definida. Isso acontece porque os elétrons ficam mudando de direção várias vezes no intervalo de um segundo.

With alternating current, it is possible to transmit and distribute electrical energy over long distances with much less loss, being more efficient than direct current. This is possible because of the transformers, which work only on alternating current. Below are several graphical representations with alternating current signals, which change between a positive and negative voltage value.

Direct current and alternating current, characteristics, and applications!
Alternating current graphs: sine wave, square wave, and triangular wave.

The number of times this polarity alternation occurs in the span of one second is defined as frequency, which is measured in Hertz. As we saw in the previous image, it is important to note that an alternating signal is not necessarily sinusoidal, as it can take on several different shapes, for example, a square or triangular wave.

What is direct current (DC)?
Unlike alternating current, the direct current has a well-defined polarity, with a negative and a positive pole. As the name itself says, the direct current always remains in a single polarity, that is, the electrons are going in only one direction, which by convention leaves the pole of the greatest potential to the pole of least potential. We emphasize that as the direct current has no variation of direction, there is no frequency quantity. In the image below we can see some examples of direct current signals.

Whenever we talk about direct current it is normal to imagine a fixed signal, without any changes, but make no mistake! There is also pulsating direct current, which although it does not change direction, also undergoes constant variations.

Direct current and alternating current, characteristics and applications!
Charts with pulsating direct current and direct current signals.

Direct current signals are easily found in batteries, batteries, computers, televisions, electronic equipment in general and others. In addition, direct current transmission systems already exist.