what is electricity? Definition
Electric current is the flow of electric charge that passes through a conductive material during a certain period of time . It is expressed in C / s, coulombs per second in the International System of Units, and the unit is known as Ampere (A).
For there to be an electric current, the electrons furthest from the nucleus of a material’s atom will have to detach and circulate freely between the atoms of said body. This phenomenon can also occur, with variations, in nature, when charged clouds give off jets of electrons that circulate through the air and cause lightning.
To measure electrical current, Ohm’s Law is used, which uses electric current, voltage and resistance.
The first experiments with electricity were in the 18th century and only had electrical charges obtained by rubbing (static) or by induction. It took until 1800 to check the constant movement of an electric charge, when the Italian physicist Alessandro Volta invented the electric battery.
Intensity of electric current
The electric intensity is the charge or electric current that circulates through an area in the unit of time, it is usually called the letter I (intensity) and its unit of measurement is usually the Ampere (A). All electrical conductors have to withstand different amounts of loads, and the higher the load, the greater the resistance of the material it is made of.
How is electric current produced?
The current is produced as a consequence of the movement of free charges (generally electrons) that are found inside a concrete conductive material in an electrical circuit. In a closed electrical circuit, the charge of electrons always goes from the negative pole to the positive pole.
What is the meaning of this current?
The real direction of the electric current always circulates the electrons from the negative pole (-) to the positive pole (+), however, the conventional direction they circulate is the opposite of the positive pole to the negative pole.
This is because in its time the existence of electrons was not known and the scientific community decided to apply that type of driving sense.
How to measure the electric current?
To measure the current of electricity through a circuit we will use the ohm’s law that we have previously discussed, the formula is as follows:
Intensity = Voltage / Resistance
The current intensity will be measured in amperes, the voltage in volts and the resistance in ohms.
Sometimes we will find alternating current sources that constantly vary the result, in that case we will use tools such as the multimeter or ammeter that will help us make a correct current measurement.
These multimeters have 2 tips that allow measuring current in series .
Types of electric current
Depending on its nature, the electric current can be of several types:
Direct current (DC)
Direct current is a type of electric current with continuous flow of electric charge through a conductor between two points of different potential and charge, one-way flow circulation, does not vary from the positive pole to the negative pole. To denominate that a current is continuous, it is necessary that the current flow does not change direction, beyond the elapsed time, it always has to flow in the same direction. The intensity can vary as long as it maintains the same polarity.
Alternating current (AC)
Alternating current is a type of electric current characterized by changes over time, both in magnitude and in direction, at regular intervals. The voltage of the alternating signal varies between its maximums and minimums in a cyclical way, half of the cycle is positive and the other half is negative. This means that the current circulates in both directions, depending on whether it is positive or negative. This cycle is constantly repeated. It is the type of energy that we use in our homes to power all electrical appliances, with a constant frequency of 50 Hertz. It was developed and powered by Nikola Tesla.
Single phase current
The single-phase current is achieved when a three-phase current phase and a neutral cable are taken, it is a system that uses the distribution, production and electrical consumption in a single phase, so the voltage always changes together.
Its most frequent use is usually for electric motors, heating or lighting.
Three phase current
The three-phase current is a system composed of 3 alternating currents that are in charge of the production, distribution and electrical consumption, their voltages are alternating and are transported by conductive systems known as R, S and T.
The advantage of this type of current is that it is more economical than others due to the savings in transformers and transport lines, as they are thinner wires than single-phase current, achieving greater performance in motors.
Electric current’s effects
Electric current offers humanity a huge number of practical benefits:
Among the effects of electric current, there are three that are usually defined: