Electric current is an electric charge in motion. It can take the form of a sudden discharge of static electricity, such as, for example, lightning. Or it could be a controlled process in generators, batteries, solar or fuel cells. Today we consider the concept of "electric current" and the conditions for the existence of electric current.
Electric Energy
Most of the electricity we use comes in the form of alternating current from the mains. It is created by generators operating according to the Faraday law of induction, due to which a changing magnetic field can induce an electric current in the conductor.
Generators have rotating coils of wire that pass through magnetic fields as they rotate. When the coils rotate, they open and close relative to the magnetic field and create an electric current that changes direction at each turn. The current goes through a full cycle back and forth 60 times per second.
Generators can be powered by steam turbines heated by coal, natural gas, oil or a nuclear reactor. Current flows from the generator through a series of transformers, where its voltage rises. The diameter of the wires determines the magnitude and strength of the current that they can carry without overheating and energy loss, and the voltage is limited only by how well the lines are isolated from the ground.
It is interesting to note that the current is carried only by one wire, and not two. Its two sides are designated as positive and negative. However, since the polarity of the alternating current changes 60 times per second, they have other names - hot (main power lines) and grounded (passing underground to close the circuit).
Why do we need electric current?
There are many possibilities for using electric current: it can lighten your house, wash and dry clothes, lift the door of your garage, make water boil in the kettle and let other household items work that make our life much easier. Nevertheless, the ability of the current to transmit information is becoming increasingly important.
When connecting to the Internet, a computer uses only a small part of the electric current, but this is what a modern person cannot imagine his life without.
The concept of electric current
Like a river flow, a stream of water molecules, an electric current is a stream of charged particles. What is it that causes him, and why does he not always go in the same direction? When you hear the word “flowing,” what do you think? Perhaps it will be a river. This is a good association because it is for this reason that electric current got its name. It is very similar to a stream of water, only instead of water molecules moving along a channel, charged particles move along a conductor.
Among the conditions necessary for the existence of an electric current, there is a paragraph providing for the presence of electrons. Atoms in a conductive material have many of these free charged particles that float around and between atoms. Their movement is random, so there is no flow in any given direction. What does it take for an electric current to exist?
Conditions for the existence of electric current include the presence of voltage. When applied to a conductor, all free electrons will move in one direction, creating a current.
Curious about electric current
It is interesting that when electrical energy is transmitted through a conductor at the speed of light, the electrons themselves move much more slowly. In fact, if you had slowly walked alongside a conductive wire, your speed would be 100 times faster than the electrons moving. This is due to the fact that they do not need to travel huge distances in order to transfer energy to each other.
Forward and alternating current
Today, two different types of current are widely used - direct and alternating. In the first, electrons move in one direction, from the “negative” side to the “positive” side. Alternating current pushes the electrons back and forth, changing the direction of flow several times per second.
Generators used in power plants to produce electricity are designed to produce alternating current. You probably never paid attention to the fact that the light in your house actually flickers, because the current direction is changing, but it happens too quickly for the eyes to recognize it.
What are the conditions for the existence of direct electric current? Why do we need both types and which one is better? These are good questions. The fact that we are still using both types of current suggests that they both serve specific purposes. As early as the 19th century, it was clear that efficient power transmission over long distances between a power plant and a house was possible only at very high voltage. But the problem was that sending really high voltage was extremely dangerous for people.
The solution to this problem was to reduce stress outside the home before sending it inside. To this day, direct current is used to transmit over long distances, mainly because of its ability to easily convert to other voltages.
How does electric current work?
The conditions for the existence of an electric current include the presence of charged particles, a conductor, and voltage. Many scientists studied electricity and found that there are two types of it: static and current.
It is the second that plays a huge role in the everyday life of any person, as it is an electric current that passes through the circuit. We use it daily to power our homes and more.
What is electric current?
When electric charges circulate from one place to another, an electric current occurs. The conditions for the existence of an electric current include, in addition to charged particles, the presence of a conductor. Most often it is a wire. Its circuit is a closed loop in which current flows from a power source. When the circuit is open, he cannot finish the path. For example, when the light in your room is turned off, the circuit is open, but when the circuit is closed, the light is on.
Current power
The conditions for the existence of an electric current in a conductor are greatly influenced by such a voltage characteristic as power. This is an indicator of how much energy is used over a period of time.
There are many different units that can be used to express this characteristic. However, electrical power is almost measured in watts. One watt is equal to one joule per second.
Electric charge in motion
What are the conditions for the existence of electric current? It can take the form of a sudden discharge of static electricity, such as lightning or a spark from friction with a woolen cloth. However, more often, when we talk about electric current, we mean a more controlled form of electricity, due to which the light is on and the devices are working. Most of the electric charge is carried by negative electrons and positive protons inside the atom. However, the latter are mainly immobilized inside atomic nuclei, therefore the work of charge transfer from one place to another is done by electrons.
The electrons in a conductive material, such as a metal, are substantially free to transfer from one atom to another along their conduction bands, which are higher electron orbits. Sufficient electromotive force or voltage creates an imbalance in the charge, which can cause the movement of electrons through the conductor in the form of an electric current.
If we draw an analogy with water, then take, for example, a pipe. When we open the valve at one end so that water gets into the pipe, we do not need to wait until this water paves all the way to its end. We get water at the other end almost instantly, because incoming water pushes water that is already in the pipe. This is what happens in the case of an electric current in a wire.
Electric current: conditions for the existence of electric current
An electric current is usually regarded as a stream of electrons. When the two ends of the battery are connected to each other using a metal wire, this charged mass passes through the wire from one end (electrode or pole) of the battery to the opposite. So, we call the conditions for the existence of an electric current:
- Charged particles.
- Conductor.
- Voltage source.
However, not all so simple. What conditions are necessary for the existence of electric current? This question can be answered in more detail by considering the following characteristics:
- Potential difference (voltage). This is one of the prerequisites. Between 2 points there should be a potential difference, meaning that the repulsive force that is created by charged particles in one place must be greater than their force at another point. Voltage sources, as a rule, are not found in nature, and electrons are distributed fairly uniformly in the environment. Nevertheless, scientists managed to invent certain types of devices where these charged particles can accumulate, thereby creating the very necessary voltage (for example, in batteries).
- Electrical resistance (conductor). This is the second important condition that is necessary for the existence of electric current. This is the path along which charged particles move. Only materials that allow the electrons to move freely act as conductors. Those who do not have this ability are called insulators. For example, a metal wire will be an excellent conductor, while its rubber sheath will be an excellent insulator.
Having carefully studied the conditions for the emergence and existence of electric current, people were able to tame this powerful and dangerous element and direct it for the benefit of mankind.