Any current appears only in the presence of a source with free charged particles. This is due to the fact that there are no substances in vacuum, including electric charges. Therefore, the vacuum is considered the best. In order for it to become possible for the passage of an electric current a, it is necessary to ensure the presence of a sufficient number of free charges. In this article we will look at what constitutes an electric current in a vacuum.

How electric current can appear in a vacuum

In order to create a full-fledged electric current in a vacuum, it is necessary to use such a physical phenomenon as thermionic emission. It is based on the property of a certain substance to emit free electrons when heated. Such electrons emerging from a heated body are called thermoelectrons, and the entire body is called an emitter.

Thermionic emission underlies the operation of vacuum devices, better known as vacuum tubes. The simplest design contains two electrodes. One of them is the cathode, which is a spiral, the material of which is molybdenum or tungsten. It is he who is heated by an electric current ohm. The second electrode is called the anode. It is in a cold state, performing the task of collecting thermionic electrons. As a rule, the anode is made in the form of a cylinder, and a heated cathode is placed inside it.

Application of current in vacuum

In the last century, vacuum tubes played a leading role in electronics. And, although they have long been replaced by semiconductor devices, the principle of operation of these devices is used in cathode ray tubes. This principle is used in welding and melting work in vacuum and other areas.

Thus, one of the varieties of current a is an electron flow flowing in vacuum. When the cathode is heated, an electric field appears between it and the anode. It is this that gives the electrons a certain direction and speed. According to this principle, an electronic lamp with two electrodes (diode) works, which is widely used in radio engineering and electronics.

The modern device is a cylinder made of glass or metal, from which air has been previously pumped out. Two electrodes, a cathode and an anode, are soldered inside this cylinder. To enhance the technical characteristics, additional grids are installed, with the help of which the electron flux is increased.

When a person learned to create and use an electric current, the quality of his life increased dramatically. Now the importance of electricity continues to increase every year. In order to learn to understand more complex issues related to electricity, you must first understand what an electric current is.

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electrical discharge

What is current

The definition of electric current is its representation in the form of a directed stream of moving particle carriers, positively or negatively charged. Charge carriers can be:

• negatively charged electrons moving in metals;
• ions in liquids or gases;
• positively charged holes from moving electrons in semiconductors.

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Electric current in a conductor

What is current is determined by the presence of an electric field. Without it, a directed flow of charged particles will not arise.

The concept of electric currentwould be incomplete without listing its manifestations:

1. Any electric current is accompanied by a magnetic field;
2. Conductors heat up as they pass;
3. Electrolytes change the chemical composition.

Conductors and semiconductors

Electric current can only exist in a conducting medium, but the nature of its flow is different:

1. In metallic conductors, there are free electrons that begin to move under the influence of an electric field. When the temperature rises, the resistance of the conductors also rises, since heat increases the movement of atoms in a chaotic manner, which interferes with free electrons;
2. In a liquid medium formed by electrolytes, the emerging electric field causes the process of dissociation - the formation of cations and anions, which move towards the positive and negative poles (electrodes) depending on the sign of the charge. Heating the electrolyte leads to a decrease in resistance due to more active decomposition of molecules;

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Electric current in electrolytes

Important! The electrolyte may be solid, but the nature of current flow in it is identical to liquid.

1. The gaseous medium is also characterized by the presence of ions that come into motion. Plasma is formed. Radiation also gives rise to free electrons participating in directed motion;
2. When creating an electric current in a vacuum, the electrons released at the negative electrode move towards the positive;
3. In semiconductors, there are free electrons that break bonds from heating. In their places are holes that have a charge with a plus sign. Holes and electrons are able to create directed motion.

Non-conductive media are called dielectric.

Important! The direction of the current corresponds to the direction of movement of charge-carrier particles with a plus sign.

Type of current

1. Constant. It is characterized by a constant quantitative value of the current and direction;
2. Variable. Over time, periodically changes its characteristics. It is divided into several varieties, depending on the parameter being changed. Predominantly, the quantitative value of the current and its direction vary along a sinusoid;
3. Eddy currents. Occur when the magnetic flux undergoes changes. Form closed circuits without moving between poles. Eddy currents cause intense heat generation, as a result, losses increase. In the cores of electromagnetic coils, they are limited by using a design of separate insulated plates instead of a solid one.

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Eddy currents in the core

Characteristics of the electrical circuit

1. Current strength. This is a quantitative measurement of the charge passing into a temporary unit over the cross section of conductors. Charges are measured in coulombs (C), the time unit is the second. The current strength is C / s. The resulting ratio was called the ampere (A), in which the quantitative value of the current is measured. The measuring device is an ammeter connected in series to the circuit of electrical connections;
2. Power. The electric current in the conductor must overcome the resistance of the medium. The work expended to overcome it during a certain time period will be power. In this case, the transformation of electricity into other types of energy - work is done. Power depends on the strength of the current, voltage. Their product will determine the active power. When multiplied by another time, the energy consumption is obtained - what the meter shows. Power can be measured in voltamperes (VA, kVA, mVA) or in watts (W, kW, mW);
3. Voltage. One of the three most important characteristics. For current to flow, it is necessary to create a potential difference between two points of a closed circuit of electrical connections. Voltage is characterized by the work produced by the electric field during the movement of a single charge carrier. According to the formula, the unit of voltage is J/C, which corresponds to a volt (V). The measuring device is a voltmeter, connected in parallel;
4. Resistance. It characterizes the ability of conductors to pass electric current. It is determined by the conductor material, length and area of ​​its section. The measurement is in ohms (Ohm).

Laws for electric current

Electric circuits are calculated using three main laws:

1. Ohm's law. It was researched and formulated by a German physicist at the beginning of the 19th century for direct current, then it was also applied to alternating current. It establishes the relationship between current, voltage and resistance. On the basis of Ohm's law, almost any electrical circuit is calculated. The basic formula: I \u003d U / R, or the current strength is in direct proportion to voltage and inversely to resistance;

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Ohm's law for a circuit section

1. Faraday's law. Refers to electromagnetic induction. The appearance of inductive currents in conductors is caused by the influence of a magnetic flux that changes over time due to the induction of an EMF (electromotive force) in a closed circuit. The induced emf modulus, measured in volts, is proportional to the rate at which the magnetic flux changes. Thanks to the law of induction, generators that produce electricity work;
2. Joule-Lenz law. It is important when calculating the heating of conductors, which is used for the design and manufacture of heating, lighting fixtures, and other electrical equipment. The law allows you to determine the amount of heat released during the passage of an electric current:

where I is the strength of the flowing current, R is the resistance, t is the time.

Electricity in the atmosphere

An electric field can exist in the atmosphere, ionization processes occur. Although the nature of their occurrence is not completely clear, there are various explanatory hypotheses. The most popular is a capacitor, as an analogue for representing electricity in the atmosphere. Its plates can mark the earth's surface and the ionosphere, between which a dielectric circulates - air.

Types of atmospheric electricity:

1. Thunderstorms. Lightning with a visible glow and thunderous peals. Lightning voltage reaches hundreds of millions of volts at a current strength of 500,000 A;

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lightning bolts

1. Fires of Saint Elmo. Corona discharge of electricity generated around wires, masts;
2. Fireball. Discharge in the form of a ball, moving through the air;
3. Polar Lights. Multicolor glow of the earth's ionosphere under the influence of charged particles penetrating from space.

Application of electricity

A person uses the beneficial properties of electric current in all areas of life:

• lighting;
• signal transmission: telephone, radio, television, telegraph;
• electric transport: trains, electric cars, trams, trolleybuses;
• creation of a comfortable microclimate: heating and air conditioning;
• Medical equipment;
• domestic use: electrical appliances;
• computers and mobile devices;
• industry: machine tools and equipment;
• electrolysis: obtaining aluminum, zinc, magnesium and other substances.

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Application of electricity

Electrical Hazard

Direct contact with electric current without protective equipment is deadly to humans. Several types of influences are possible:

• thermal burn;
• electrolytic splitting of blood and lymph with a change in its composition;
• convulsive muscle contractions can provoke heart fibrillation up to its complete stop, disrupt the functioning of the respiratory system.

Important! The current felt by a person starts from a value of 1 mA, if the current value is 25 mA, serious negative changes in the body are possible.

The most important characteristic of electric current is that it can do useful work for a person: light a house, wash and dry clothes, cook dinner, heat a home. Now a significant place is occupied by its use in the transmission of information, although this does not require a large consumption of electricity.

Video

Charge in motion. It can take the form of a sudden discharge of static electricity, such as lightning. Or it could be a controlled process in generators, batteries, solar or fuel cells. Today we will consider the very concept of "electric current" and the conditions for the existence of an electric current.

Electric Energy

Most of the electricity we use comes in the form of alternating current from the electrical grid. It is created by generators that work according to Faraday's law of induction, due to which a changing magnetic field can induce an electric current in a conductor.

Generators have spinning coils of wire that pass through magnetic fields as they spin. As the coils rotate, they open and close with respect to the magnetic field and create an electrical current that changes direction with 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. From the generator, the current passes through a series of transformers, where its voltage increases. The diameter of the wires determines the amount and strength of current they can carry without overheating and wasting power, and voltage is limited only by how well the lines are insulated from ground.

It is interesting to note that the current is carried by only one wire, not two. Its two sides are designated as positive and negative. However, since the polarity of alternating current changes 60 times per second, they have other names - hot (main power lines) and grounded (passing underground to complete the circuit).

Why is electricity needed?

There are many uses for electricity: it can light up your house, wash and dry your clothes, lift your garage door, boil water in a kettle, and power other household items that make our lives so much easier. However, the ability of the current to transmit information is becoming increasingly important.

When connected to the Internet, a computer uses only a small part of the electric current, but this is something without which a modern person cannot imagine his life.

The concept of electric current

Like a river current, a stream of water molecules, an electric current is a stream of charged particles. What is it that causes it, and why doesn't it always go in the same direction? When you hear the word flow, what do you think of? Perhaps it will be a river. It's a good association, because that's the reason the electric current got its name. It is very similar to the flow of water, only instead of water molecules moving along the channel, charged particles move along the conductor.

Among the conditions necessary for the existence of an electric current, there is an item that provides for the presence of electrons. Atoms in a conductive material have many of these free charged particles that float around and between the atoms. Their movement is random, so there is no flow in any given direction. What does it take for an electric current to exist?

The conditions for the existence of electric current include the presence of voltage. When it is applied to a conductor, all free electrons will move in the same direction, creating a current.

Curious about electric current

Interestingly, when electrical energy is transmitted through a conductor at the speed of light, the electrons themselves move much more slowly. In fact, if you walked leisurely next to a conductive wire, your speed would be 100 times faster than the electrons are moving. This is due to the fact that they do not need to travel huge distances to transfer energy to each other.

Direct and alternating current

Today, two different types of current are widely used - direct and alternating. In the first, the electrons move in one direction, from the "negative" side to the "positive" side. The alternating current pushes the electrons back and forth, changing the direction of the flow several times per second.

Generators used in power plants to produce electricity are designed to produce alternating current. You probably never noticed that the light in your house is actually flickering as the current direction changes, but it happens too fast for the eyes to recognize.

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 still use both types of current suggests that they both serve specific purposes. As far back as the 19th century, it was clear that efficient transmission of power over long distances between a power plant and a house was possible only at very high voltages. But the problem was that sending really high voltage was extremely dangerous for people.

The solution to this problem was to reduce the stress outside the home before sending it inside. To this day, direct electric current is used for transmission over long distances, mainly because of its ability to easily convert to other voltages.

How electric current works

The conditions for the existence of an electric current include the presence of charged particles, a conductor, and voltage. Many scientists have 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 daily 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 in a circuit from one place to another, an electric current is generated. 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 circuit in which current flows from a power source. When the circuit is open, he cannot complete the journey. For example, when the light in your room is 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 a measure of how much energy is being used over a given 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 an 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. More often, however, when we talk about electric current, we mean a more controlled form of electricity that makes lights and appliances work. Most of the electrical charge is carried by the negative electrons and positive protons within the atom. However, the latter are mostly immobilized inside atomic nuclei, so the work of transferring charge from one place to another is done by electrons.

Electrons in a conductive material such as a metal are largely free to move from one atom to another along their conduction bands, which are the higher electron orbits. A sufficient electromotive force or voltage creates a charge imbalance that can cause electrons to move through a conductor in the form of an electric current.

If we draw an analogy with water, then take, for example, a pipe. When we open a valve at one end to let water enter the pipe, we don't have to wait for that water to work its way all the way to the end of the pipe. We get water at the other end almost instantly because the incoming water pushes the 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 an electric current

Electric current is usually viewed as a flow of electrons. When the two ends of the battery are connected to each other with a metal wire, this charged mass flows through the wire from one end (electrode or pole) of the battery to the opposite. So, let's call the conditions for the existence of an electric current:

1. charged particles.
2. Conductor.
3. Voltage source.

However, not all so simple. What conditions are necessary for the existence of an 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 the 2 points there must 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, do not occur in nature, and electrons are distributed fairly evenly 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 an electric current. This is the path along which charged particles travel. Only those materials that allow 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.

This is the ordered movement of certain charged particles. In order to competently use the full potential of electricity, it is necessary to clearly understand all the principles of the device and the operation of electric current. So, let's figure out what work and current power are.

Where does electrical current come from?

Despite the apparent simplicity of the question, few are able to give an intelligible answer to it. Of course, nowadays, when technology is developing at an incredible speed, a person does not particularly think about such elementary things as the principle of operation of an electric current. Where does electricity come from? Surely many will answer "Well, from the socket, of course" or simply shrug their shoulders. Meanwhile, it is very important to understand how the current works. This should be known not only to scientists, but also to people who are in no way connected with the world of sciences, for their general versatile development. But to be able to correctly use the principle of current operation is not for everyone.

So, first you need to understand that electricity does not arise from nowhere: it is produced by special generators that are located at various power plants. Thanks to the work of rotating the blades of turbines, steam obtained as a result of heating water with coals or oil generates energy, which is subsequently converted into electricity with the help of a generator. The generator is very simple: in the center of the device is a huge and very strong magnet, which causes electric charges to move along copper wires.

How does electricity reach our homes?

After a certain amount of electric current has been obtained with the help of energy (thermal or nuclear), it can be supplied to people. Such a supply of electricity works as follows: in order for electricity to successfully reach all apartments and enterprises, it must be “pushed”. And for this you need to increase the force that will do it. It is called the voltage of the electric current. The principle of operation is as follows: the current passes through the transformer, which increases its voltage. Further, the electric current flows through cables installed deep underground or at a height (because the voltage sometimes reaches 10,000 volts, which is deadly for humans). When the current reaches its destination, it must again pass through the transformer, which will now reduce its voltage. It then passes through wires to installed shields in apartment buildings or other buildings.

The electricity carried through the wires can be used thanks to the system of sockets, connecting household appliances to them. Additional wires are carried in the walls, through which electric current flows, and thanks to it, the lighting and all the appliances in the house work.

What is current work?

The energy that an electric current carries in itself is converted over time into light or heat. For example, when we turn on a lamp, the electrical form of energy is converted into light.

Speaking in an accessible language, the work of the current is the action that electricity itself produced. Moreover, it can be very easily calculated by the formula. Based on the law of conservation of energy, we can conclude that electrical energy has not disappeared, it has completely or partially changed into another form, while giving off a certain amount of heat. This heat is the work of the current when it passes through the conductor and heats it (heat exchange occurs). This is how the Joule-Lenz formula looks like: A \u003d Q \u003d U * I * t (work is equal to the amount of heat or the product of the current power and the time during which it flowed through the conductor).

What does direct current mean?

Electric current is of two types: alternating and direct. They differ in that the latter does not change its direction, it has two clamps (positive "+" and negative "-") and always starts its movement from "+". And alternating current has two terminals - phase and zero. It is because of the presence of one phase at the end of the conductor that it is also called single-phase.

The principles of the device of single-phase alternating and direct electric current are completely different: unlike direct, the alternating current changes both its direction (forming a flow both from the phase towards zero, and from zero towards the phase), and its magnitude. So, for example, alternating current periodically changes the value of its charge. It turns out that at a frequency of 50 Hz (50 oscillations per second), the electrons change the direction of their movement exactly 100 times.

Where is direct current used?

Direct electric current has some features. Due to the fact that it flows strictly in one direction, it is more difficult to transform it. The following elements can be considered as sources of direct current:

• batteries (both alkaline and acid);
• conventional batteries used in small appliances;
• as well as various devices such as converters.

DC operation

What are its main characteristics? These are work and current power, and both of these concepts are very closely related to each other. Power means the speed of work per unit time (per 1 s). According to the Joule-Lenz law, we obtain that the work of a direct electric current is equal to the product of the strength of the current itself, the voltage and the time during which the work of the electric field was completed to transfer charges along the conductor.

This is how the formula for finding the work of the current, taking into account Ohm's law of resistance in conductors, looks like: A \u003d I 2 * R * t (work is equal to the square of the current strength multiplied by the value of the resistance of the conductor and once again multiplied by the value of the time for which the work was done).

Current and voltage are quantitative parameters used in electrical circuits. Most often, these values ​​​​change over time, otherwise there would be no point in the operation of the electrical circuit.

Voltage

Conventionally, the voltage is indicated by the letter U. The work done to move a unit of charge from a point of low potential to a point of high potential is the voltage between these two points. In other words, this is the energy released after the transition of a unit of charge from a high potential to a small one.

Voltage can also be called the potential difference, as well as the electromotive force. This parameter is measured in volts. To move 1 coulomb of charge between two points that have a voltage of 1 volt, you need to do 1 joule of work. Coulombs measure electric charges. 1 pendant is equal to the charge of 6x10 18 electrons.

Voltage is divided into several types, depending on the types of current.

• Constant pressure . It is present in electrostatic circuits and DC circuits.
• AC voltage . This type of voltage is available in circuits with sinusoidal and alternating currents. In the case of a sinusoidal current, voltage characteristics such as:
  voltage fluctuation amplitude is its maximum deviation from the x-axis;
  instant voltage, which is expressed at a certain point in time;
  operating voltage, is determined by the active work of the 1st half-cycle;
  medium rectified voltage, determined by the modulus of the rectified voltage for one harmonic period.

When transmitting electricity through overhead lines, the arrangement of supports and their dimensions depend on the magnitude of the applied voltage. The voltage between phases is called line voltage , and the voltage between ground and each of the phases is phase voltage . This rule applies to all types of overhead lines. In Russia, in household electrical networks, the standard is a three-phase voltage with a linear voltage of 380 volts, and a phase voltage value of 220 volts.

Electricity

The current in an electrical circuit is the speed of electrons at a certain point, measured in amperes, and is indicated on the diagrams by the letter " I". Derived units of the ampere are also used with the appropriate prefixes milli-, micro-, nano, etc. A current of 1 ampere is generated by moving a unit of charge of 1 coulomb in 1 second.

Conventionally, it is considered that the current flows in the direction from the positive potential to the negative one. However, from the course of physics it is known that the electron moves in the opposite direction.

You need to know that the voltage is measured between 2 points on the circuit, and the current flows through one specific point of the circuit, or through its element. Therefore, if someone uses the expression "voltage in resistance", then this is incorrect and illiterate. But often we are talking about voltage at a certain point in the circuit. This refers to the voltage between ground and this point.

Voltage is formed from the impact on electrical charges in generators and other devices. Current is generated by applying voltage to two points in a circuit.

To understand what current and voltage are, it would be more correct to use. On it you can see the current and voltage, which change their values ​​over time. In practice, the elements of an electrical circuit are connected by conductors. At certain points, the circuit elements have their own voltage value.

Current and voltage obey the rules:

• The sum of the currents entering the point is equal to the sum of the currents leaving the point (charge conservation rule). Such a rule is Kirchhoff's law for current. The point of entry and exit of current in this case is called a node. A consequence of this law is the following statement: in a series electrical circuit of a group of elements, the current for all points is the same.
• In a parallel circuit of elements, the voltage across all elements is the same. In other words, the sum of voltage drops in a closed circuit is zero. This Kirchhoff's law applies to stresses.
• The work done per unit time by the circuit (power) is expressed as follows: P \u003d U * I. Power is measured in watts. 1 joule of work done in 1 second is equal to 1 watt. Power is distributed in the form of heat, is spent on mechanical work (in electric motors), is converted into radiation of various types, and accumulates in tanks or batteries. When designing complex electrical systems, one of the challenges is the thermal load of the system.

Electric current characteristic

A prerequisite for the existence of current in an electrical circuit is a closed circuit. If the circuit breaks, then the current stops.

Everything in electrical engineering works on this principle. They break the electrical circuit with moving mechanical contacts, and this stops the flow of current, turning off the device.

In the energy industry, electric current occurs inside current conductors, which are made in the form of tires, and other parts that conduct current.

There are also other ways to create an internal current in:

• Liquids and gases due to the movement of charged ions.
• Vacuum, gas and air using thermionic emission.
• due to the movement of charge carriers.

Conditions for the occurrence of electric current

• Heating conductors (not superconductors).
• Application to charge carriers of potential difference.
• Chemical reaction with the release of new substances.
• The effect of a magnetic field on a conductor.

Current Waveforms

• Straight line.
• Variable harmonic sine wave.
• A meander that looks like a sine wave, but has sharp corners (sometimes the corners can be smoothed).
• A pulsating form of one direction, with an amplitude that fluctuates from zero to the largest value according to a certain law.

Types of work of electric current

• Light emitted by lighting devices.
• Generating heat with heating elements.
• Mechanical work (rotation of electric motors, action of other electrical devices).
• Creation of electromagnetic radiation.

Negative phenomena caused by electric current

• Overheating of contacts and current-carrying parts.
• The occurrence of eddy currents in the cores of electrical devices.
• Electromagnetic radiation to the external environment.

The creators of electrical devices and various circuits when designing must take into account the above properties of electric current in their designs. For example, the harmful effect of eddy currents in electric motors, transformers and generators is reduced by blending the cores used to transmit magnetic fluxes. Core blending is its manufacture not from a single piece of metal, but from a set of separate thin plates of special electrical steel.

But, on the other hand, eddy currents are used to operate microwave ovens, ovens, operating on the principle of magnetic induction. Therefore, we can say that eddy currents are not only harmful, but also beneficial.

An alternating current with a signal in the form of a sinusoid can vary in frequency of oscillation per unit of time. In our country, the industrial current frequency of electrical devices is standard, and is equal to 50 hertz. In some countries, the current frequency is 60 hertz.

For various purposes in electrical engineering and radio engineering, other frequency values ​​\u200b\u200bare used:

• Low frequency signals with lower current frequency.
• High frequency signals, which are much higher than the current frequency of industrial use.

It is believed that electric current occurs when electrons move inside a conductor, so it is called conduction current. But there is another type of electric current, which is called convection. It occurs when charged macrobodies move, for example, raindrops.

Electric current in metals

The movement of electrons under the influence of a constant force on them is compared with a parachutist who descends to the ground. In these two cases, uniform motion occurs. The force of gravity acts on the skydiver, and the force of air resistance opposes it. The electric field force acts on the movement of electrons, and the ions of the crystal lattices resist this movement. The average speed of the electrons reaches a constant value, as well as the speed of the skydiver.

In a metal conductor, the speed of one electron is 0.1 mm per second, and the speed of an electric current is about 300,000 km per second. This is because electric current flows only where voltage is applied to the charged particles. Therefore, a high current flow rate is achieved.

When moving electrons in a crystal lattice, there is the following regularity. The electrons do not collide with all the ions they meet, but only with every tenth of them. This is explained by the laws of quantum mechanics, which can be simplified as follows.

The movement of electrons is hindered by large ions that resist. This is especially noticeable when metals are heated, when heavy ions "swing", increase in size and reduce the electrical conductivity of the crystal lattices of the conductor. Therefore, when metals are heated, their resistance always increases. As the temperature decreases, the electrical conductivity increases. By reducing the temperature of the metal to absolute zero, the effect of superconductivity can be achieved.