Can you imagine the current world without electricity? Not a good thought, right? Electricity is fundamental today and we need to learn as much as possible about it. Electricity has electrical quantities, and it is about one of them that this article will address the famous electric current!
Electric Current: What is it?
Electric current by definition is the ordered movement of electrical charges within a conductor for a given time. This electrical charge is driven to move through another electrical quantity called electrical voltage.
In a conductor, there are free electrons that are disorganized and stay in motion, but when the voltage reaches the free electrons that are in the conductors, they take the same direction, organizing themselves and forming an electron current, the electric current (I).
Electric Current: Intensity
The intensity of an electric current is demonstrated by its universal unit, which is the ampere (A). It is possible to calculate the electric current with an account involving two factors, the electric charge (Q) expressed in coulomb (C), and a time interval (Δt) in seconds (s), thus, the intensity of the electric current ( I) is the result of dividing the load (Q) by the time interval (Δt). See the formula below.
Current intensity formula
Electric Current Intensity calculation formula!
There are also other ways to calculate the electric current, for this it is necessary to have information on voltage, resistance or power, see below the formulas.
Electric current formulas
Electric current calculation formulas!
Electric Current: Classification
Electric current is classified into two types of current, direct current and alternating current.
Direct current is the current that has no change in direction. This current has its polarity well defined with a negative and a positive pole, and the current remains in one polarity continuously, as its own name implies.
The electrons in the direct current move in a single direction, they are attracted to the point with the least potential and leaving the point of greatest potential. As there is no variation, the direct current has no frequency.
The direct current is expressed in graphs, it can be a constant line or not, because there is also pulsating direct current, which does not vary in direction, but in voltage. See below the two graphic representations.
Straight and pulsating direct current chart
Alternating current is the current that varies in the direction of the electrons and therefore does not have a polarity defined as in direct current. The electrons in the alternating current move in two directions, from positive to negative and vice versa several times in one second. This super fast movement is what is called the current frequency.
This type of current is used mainly in the transmission and distribution of energy over long distances, as it does not have so many energy losses, which is an advantage over direct current. There are several types of alternating signals, see below some graphical representations.
Sinusoidal, square and triangular alternating current
Alternating Current Charts
Electric Current Direction
There are two senses of the electric current to study, the conventional sense and the real sense.
In the century. XVIII With the beginning of the study on electricity, it was noticed that electricity was polarized, that is, it had poles and consequently it had a sense for the electric current to travel.
Due to the comparison with fluids, they believed that the direction of the electric current was from the point of greatest potential that was positive to the point of least potential that was negative, thus forming the sense that today is called the conventional sense.
In the century. XIX with the study of the structure of atoms, it was realized that the positive charges (protons) were in the nucleus of atoms and because they have a very strong atomic bond they did not move freely.
It was also observed that free electrons could move freely, thus occurring the theory of real sense, where free electrons moved towards positive poles due to attraction.
Electric current behavior in each type of circuit
Electrical circuit is the manifestation of a path for the electric current to travel, and in this path the current has a behavior. As there are basically three types of circuit, the series circuit, the parallel circuit and the mixed circuit, let’s talk about the behavior of the electric current in these circuits.
Series circuit is a circuit that connects two or more loads in sequence, so that these loads are in series with each other, where they have only one point in common. The current that will pass through this circuit will be the same, so all loads will receive the same current. What will be different in this type of circuit is the voltage, which can be changed if the load resistances are not the same.
See what a series circuit looks like
Example of a Series Circuit!
Parallel circuit is a circuit made from two loads, where in each load to be added a derivation for the load is made, so that all loads are in parallel with each other, that is, the loads have two points in common.
The electric current in this circuit is divided according to the number of charges in parallel, so all charges receive a current proportional to their resistance, the voltage in this case will be the same distributed by the source for all charges.
See what a parallel circuit looks like.
Example of a Parallel Circuit!
Mixed circuit is a circuit that performed with the previous two, it has both utilities and functions, so that they have parallel loads and loads connected in series.
this circuit the electric current behaves in both ways, the charges in parallel are derived and receive a current proportional to its resistance. The loads connected in series will receive an equal amount of the current that is available, varying only the voltage if the resistance is different.