What is electrical. What is electric current? The nature of electricity. Electric current: conditions for the existence of an electric current
This article shows that in modern physics the concept of electric current is mythologized and has no evidence of its modern interpretation.
From the standpoint of etherodynamics, the representation is substantiated electric current as a flow of photon gas and the conditions for its existence.
Introduction. In the history of science, the 19th century was called the century of electricity. The amazing 19th century, which laid the foundations for the scientific and technological revolution that so changed the world, began with a galvanic cell - the first battery, a chemical current source (voltaic column) and the discovery of electric current. Studies of electric current, carried out on a large scale in the first XIX years in. gave impetus to the penetration of electricity into all spheres of human life. Modern life is unthinkable without radio and television, telephone, smartphone and computer, all kinds of lighting and heating devices, machines and devices, which are based on the possibility of using electric current.
However, the widespread use of electricity from the first days of the discovery of electric current is in deep contradiction to its theoretical justification. Neither nineteenth-century nor modern physics can answer the question: what is an electric current? For example, in the following statement from the Encyclopædia Britannica:
“The question: “What is electricity?”, like the question: “What is matter?”, lies outside the realm of physics and belongs to the realm of metaphysics.”
The first widely known experiments with electric current were carried out by the Italian physicist Galvani at the end of the 18th century. Another Italian physicist Volta created the first device capable of producing a long-term electric current - a galvanic cell. Volta showed that the contact of dissimilar metals leads them to an electrical state and that from the addition of a liquid that conducts electricity to them, a direct current of electricity is formed. The current obtained in the named case is called galvanic current and the phenomenon itself is called galvanism. At the same time, the current in Volt's representation is the movement of electrical fluids - fluids.
A significant shift in understanding the essence of electric current was made
M. Faraday. He proved the identity of certain types of electricity coming from different sources. The most important work was the experiments on electrolysis. The discovery was taken as one of the proofs that moving electricity is in fact identical to electricity due to friction, i.e. static electricity. His series of ingenious experiments on electrolysis served as convincing confirmation of the idea, the essence of which boils down to the following: if matter has an atomic structure by nature, then in the process of electrolysis each atom receives a certain amount of electricity.
In 1874, the Irish physicist J. Stoney (Stony) made a report in Belfast, in which he used Faraday's laws of electrolysis as the basis for the atomic theory of electricity. Based on the magnitude of the total charge that passed through the electrolyte, and a rather rough estimate of the number of hydrogen atoms released on the cathode, Stoney obtained a number of the order of 10 -20 C for an elementary charge (in modern units). This report was not fully published until 1881, when a German scientist
G. Helmholtz in one of his lectures in London noted that if one accepts the hypothesis of the atomic structure of elements, one cannot help but come to the conclusion that electricity is also divided into elementary portions or “atoms of electricity”. This conclusion of Helmholtz, in essence, followed from the results of Faraday on electrolysis and resembled the statement of Faraday himself. Faraday's studies of electrolysis played a fundamental role in the development of the electronic theory.
In 1891, Stoney, who supported the idea that Faraday's laws of electrolysis meant the existence of a natural unit of charge, coined the term "electron".
However, soon the term electron, introduced by Stoney, loses its original essence. In 1892 H. Lorenz forms his own theory of electrons. According to him, electricity arises from the movement of tiny charged particles - positive and negative electrons.
AT late XIX in. began to develop electron theory conductivity. The beginnings of the theory were given in 1900 by the German physicist Paul Drude. Drude theory entered into training courses physics under the name classical theory electrical conductivity of metals. In this theory, electrons are likened to atoms of an ideal gas that fills the crystal lattice of a metal, and the electric current is represented as a flow of this electron gas.
After the presentation of Rutherford's model of the atom, a series of measurements of the magnitude of the elementary charge in the 20s of the XX century. in physics, the concept of electric current was finally formed as a flow of free electrons, the structural elements of an atom of matter.
However, the model of free electrons turned out to be inconsistent in explaining the essence of electric current in liquid electrolytes, gases and semiconductors. To support the existing theory of electric current, new electric charge carriers were introduced - ions and holes.
Based on the above, in modern physics, the final concept by modern standards has been formed: electric current is the directed movement of electric charge carriers (electrons, ions, holes, etc.).
The direction of movement of positive charges is taken as the direction of the electric current; if the current is created by negatively charged particles (for example, electrons), then the direction of the current is considered opposite to the movement of particles.
Electric current is called constant if the strength of the current and its direction do not change over time. For the occurrence and maintenance of current in any medium, two conditions must be met: - the presence of free electric charges in the medium; — creation of an electric field in the medium.
However, this representation of the electric current turned out to be untenable in describing the phenomenon of superconductivity. In addition, as it turned out, there are many contradictions in the specified representation of the electric current when describing the functioning of almost all types of electronic devices. The need to interpret the concept of electric current in different conditions and in different types of electronic devices, on the one hand, as well as a misunderstanding of the essence of electric current, on the other hand, has forced modern physics to make an electron from an electric charge carrier, “figaro” (“free”, “fast”, “knocked out”, “emitted”, “braking”, “relativistic”, “photo”, “thermo”, etc.), which finally brought up the question “ what is electric current? into a dead end.
The significance of the theoretical representation of electric current in modern conditions has grown significantly not only due to the widespread use of electricity in human life, but also because of the high cost and technical feasibility, for example, scientific megaprojects implemented by all developed countries of the world, in which the concept of electric current plays a significant role.
Etherdynamic concept of electric current representation. From the above definition it follows that the electric current is a directed movement carriers of electric charges. Obviously, the discovery of the physical essence of the electric current is in solving the problem of the physical essence of the electric charge and what is the carrier of this charge.
The problem of the physical essence of the electric charge is not a solved problem, both by classical physics and modern quantum physics throughout the history of the development of electricity. The solution of this problem turned out to be possible only with the use of the methodology of etherodynamics, a new concept of physics of the 21st century.
According to the etherodynamic definition: electric charge is a measure of the movement of the flow of ether ... . Electric charge is a property inherent in all elementary particles and only. Electric charge is a sign-definite quantity, that is, always positive.
From the indicated physical essence of the electric charge, the incorrectness of the above definition of the electric current follows in terms of the fact that ions, holes, etc. cannot be the cause of electric current due to the fact that they are not carriers of electric charge, since they are not elements of the organizational level of physical matter - elementary particles (according to the definition).
Electrons, as elementary particles, have an electric charge, however, according to the definition: are one of the basic structural units of matter, formelectron shells atoms , the structure of which determines the majority of optical, electrical, magnetic, mechanical andchemical properties substances cannot be mobile (free) carriers of electric charge. The free electron is a myth created modern physics for the interpretation of the concept of electric current, which does not have a single practical or theoretical evidence. Obviously, as soon as the “free” electron leaves the atom of the substance, forming an electric current, there must certainly be changes in the physicochemical properties of this substance (according to the definition), which is not observed in nature. This assumption was confirmed by the experiments of the German physicist Karl Victor Eduard Rikke: “the passage of current through metals (conductors of the first kind) is not accompanied by a chemical change in them.” At present, the dependence of the physicochemical properties of a substance on the presence of one or another electron in an atom of a substance is well studied and experimentally confirmed, for example, in the work.
There is also a reference to experiments performed for the first time in 1912 by L. I. Mandelstam and N. D. Papaleksi, but not published by them. Four years later (1916) R. C. Tolman and T. D. Stuart published the results of their experiments, which turned out to be similar to those of Mandelstam and Papaleksi. In modern physics, these experiments serve as direct confirmation that free electrons should be considered as carriers of electricity in a metal.
In order to understand the incorrectness of these experiments, it is enough to consider the scheme and methodology of the experiment, in which an inductance coil was used as a conductor, which spun around its axis and stopped abruptly. The coil was connected to a galvanometer using sliding contacts, which registered the occurrence of inertial EMF. In fact, we can say that in this experiment, the role of external forces that create the EMF was played by the force of inertia, i.e., if there are free charge carriers in the metal that have mass, then they must obeylaw of inertia . Statement " they must obeylaw of inertia ” erroneous in the sense that according to the level approach in the organization of physical matter, electrons, as elements of the “elementary particles” level, obey only the laws of electro- and gas dynamics, i.e. the laws of mechanics (Newton) are not applicable to them.
To make this assumption convincing, consider the well-known problem 3.1: calculate the ratio of electrostatic (Fe) and gravitational (Fgr) forces of interaction between two electrons, between two protons.
Solution: for electrons Fe / Fgr = 4 10 42 , for protons Fe / Fgr = 1.24 10 36 , i.e. the influence of gravitational forces is so small that it is not necessary to take them into account. This statement is also true for the forces of inertia.
This means that the expression for the EMF (proposed by R. C. Tolman and T. D. Stewart), based on its definition in terms of external forces Fside, acting on the charges inside the conductor subjected to braking:
ε = 1/e ∫F side∙dl,
incorrect in its formulation, due to the fact that Fside → 0.
Nevertheless, as a result of the experiment, a short-term deviation of the galvanometer needle was observed, which requires explanation. To understand this process, one should pay attention to the galvanometer itself, for which the so-called ballistic galvanometer was used. Its instructions for use have such an option.
A ballistic galvanometer can be used as a webermeter (i.e., measure the magnetic flux through a closed conductor, such as a coil), for this, an inductive coil is connected to the contacts of the ballistic galvanometer, which is placed in a magnetic field. If, after this, the coil is abruptly removed from magnetic field or rotate so that the axis of the coil is perpendicular to the field lines, then you can measure the charge that has passed through the coil, due to electromagnetic induction, because. the change in magnetic flux is proportional to the passed charge, by calibrating the galvanometer accordingly, it is possible to determine the change in flux in webers.
From the foregoing, it is obvious that the use of a ballistic galvanometer as a webermeter corresponds to the method of the experiment of R. C. Tolman and T. D. Stewart on the observation of inertial current in metals. The question of the source of the magnetic field remains open, which, for example, could be the Earth's magnetic field. The influence of an external magnetic field by R. C. Tolman and T. D. Stewart was not taken into account and was not studied, which led to the mythologization of the results of the experiment.
The essence of electric current. From the above it follows that the answer to the question, what is electric current? is also a solution to the problem of an electric charge carrier. Based on the existing ideas of this problem, it is possible to formulate a number of requirements that an electric charge carrier must satisfy. Namely: the carrier of electric charge must be an elementary particle; the carrier of electric charge must be a free and long-lived element; the carrier of electric charge must not destroy the structure of the atom of the substance.
A simple analysis of the existing facts allows us to conclude that only one element of the “elementary particles” level of physical matter satisfies the above requirements: an elementary particle - a photon.
The totality of photons together with the medium (ether) in which they exist form a photon gas.
Taking into account the physical nature of the photon and the above information, we can give the following definition:
electric current is a flow of photon gas designed to carry energy.
To understand the mechanism of electric current movement, consider the well-known model of methane gas transportation. Simplified, it includes a main pipeline that delivers methane gas from a gas field to a place of consumption. To move methane gas through the main pipeline, the condition must be met - the pressure of methane gas at the beginning of the pipeline must be greater than the pressure of methane gas at its end.
By analogy with the transportation of methane gas, let's consider a scheme for the movement of electric current, consisting of a battery (source of electric current), which has two contacts “+” and “-“ and a conductor. If a metal conductor is connected to the battery contacts, then we get a model of the movement of an electric current, similar to the transportation of methane gas.
The condition for the existence of an electric current in a conductor, by analogy with the model of transportation of methane gas, is the presence of: a source (gas) of increased pressure, i.e. a source of high concentration of electric charge carriers; pipeline - conductor; gas consumer, i.e., an element that provides a decrease in gas pressure, i.e., an element (drain) that provides a decrease in the concentration of electric charge carriers.
The difference between electrical circuits from gas, hydro, etc. is that structurally, the source and drain are performed in one node (chemical current source-battery, electric generator, etc.). The mechanism of the flow of electric current is as follows: after connecting the conductor to the battery, for example, a chemical current source, a chemical reduction reaction occurs in the “+” (anode) contact zone, as a result of which photons are generated, i.e., a zone of increased carrier concentration is formed electric charge. At the same time, in the “-” contact zone (cathode), under the influence of photons that have appeared in this zone as a result of the flow through the conductor, an oxidation reaction (photon consumption) occurs, i.e., a zone of reduced concentration of electric charge carriers is formed. Carriers of electric charge (photons) from the zone of high concentration (source) move along the conductor to the zone of low concentration (sink). Thus, the third-party force or electromotive force (EMF) that provides electric current in the circuit is the difference in concentration (pressure) of electric charge carriers (photons) formed as a result of the operation of a chemical current source.
This circumstance once again emphasizes the validity of the main conclusion of energy dynamics, according to which force fields (including the electric field) are created not by masses, charges and currents by themselves, but by their uneven distribution in space.
Based on the considered essence of the electric current, the absurdity of the experience of R. C. Tolman and T. D. Stewart on the observation of inertial current in metals is obvious. Ways to generate photons by changing the speed mechanical movement any macroscopic body does not currently exist in nature.
An interesting aspect of the above representation of the electric current is its comparison with the representation of the concept of “light”, considered in the work: light is a stream of photon gas ... . This comparison allows us to conclude that light is an electric current. The difference in these concepts lies only in the spectral composition of photons that form light or electric current, for example, in metal conductors. For a more convincing understanding of this circumstance, consider a scheme for generating electric current using a solar battery. The flow of sunlight (photons in the visible range) from the source (the sun) reaches the solar battery, which converts the incident light into an electric current (photon flow), which is supplied to the consumer (drain) through a metal conductor. AT this case the solar battery acts as a converter of the spectrum of the photon flux emitted by the sun into the spectrum of photons of electric current in a metal conductor.
conclusions. In modern physics, there is no evidence that the electric current is the directed movement of electrons or any other particles. Against, modern ideas about the electron, electric charge and Rikke's experiments show the fallacy of this concept of electric current.
Justification of the set of requirements for the carrier of electric charge, taking into account its etherodynamic essence, made it possible to establish that the electric current it is a stream of photon gas designed to carry energy.
The movement of electric current is carried out from the zone of high concentration of photons (source) to the zone of low concentration (drain).
In order to generate and maintain a current in any medium, three conditions must be met: maintaining (generation) of a high concentration of photons in the source zone, the presence of a conductor that ensures the flow of photons, and the creation of a photon consumption zone in the sink region.
Electricity Electron.
Lyamin V.S. , Lyamin D. V. Lvov
Every person has an abstract concept of electric current. For an electrical appliance, the power source is something like a source of air for any breathing organism. But on these comparisons, the understanding of the nature of the phenomenon is limited, and only specialists understand the essence deeper.
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In the school curriculum, everyone takes a course in physics, which describes the basic concepts and laws of electricity. The dry, scientific approach is of no interest to children, so most adults have no idea what an electric current is, why it occurs, how it has a unit of measurement, and how anything can move through fixed metal wires, Yes, even make electrical appliances work.
In simple words about electric current
The standard definition from a school textbook on physics succinctly describes the phenomenon of electric current. But to be honest, you can fully understand this if you study the subject much deeper. After all, the information is presented in another language - scientific. Much easier to understand nature physical phenomenon, if you describe everything in a familiar language, understandable to any person. For example, current in metal.
We should start with the fact that everything that we consider to be solid and motionless is so only in our imagination. A piece of metal lying on the ground is a monolithic motionless body in human understanding. For an analogy, imagine our planet in space, looking at it from the surface of Mars. The earth seems to be an integral, motionless body. If you approach its surface, it becomes obvious that this is not a monolithic piece of matter, but a constant movement: water, gases, living beings, lithospheric plates- all this is constantly moving, although this is not visible from far space.
Let's return to our piece of metal lying on the ground. It is motionless because we look at it from the side as a monolithic object. At the atomic level, it consists of constantly moving tiny elements. They are different, but among all, we are interested in electrons, which create an electromagnetic field in metals that generates the same current. The word "current" must be taken literally, because when elements with an electric charge move, that is, "flow", from one charged object to another, then an "electric current" occurs.
Having dealt with the basic concepts, we can derive a general definition:
Electric current is the flow of charged particles moving from a body with a higher charge to a body with a lower charge.
To understand the essence even more precisely, you need to delve into the details and get answers to several basic questions.
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Answers to the main questions about electric current
After formulating the definition, several logical questions arise.
- What causes the current to "flow", that is, to move?
- If the smallest elements of the metal are constantly moving, then why does it not deform?
- If something flows from one object to another, does the mass of these objects change?
The answer to the first question is simple. As water flows from a high point to a low point, so will electrons flow from a body with a high charge to a body with a low one, obeying the laws of physics. And the “charge” (or potential) is the number of electrons in the body, and the more of them, the higher the charge. If a contact is made between two bodies with different charges, electrons from a more charged body will flow into a less charged one. So a current will arise, which will end when the charges of the two contacting bodies are equalized.
To understand why a wire does not change structure, despite the fact that it is constantly moving, you need to imagine it as a large house in which people live. The size of the house will not change in terms of how many people get in and out and move around inside. In this case, a person is an analogue of an electron in a metal - it moves freely and does not have much mass compared to the whole building.
If electrons move from one body to another, why does the mass of the bodies not change? The fact is that the weight of an electron is so small that even if all the electrons are removed from the body, its mass will not change.
What is the unit of measure for current strength
- Current strength.
- Voltage.
- Resistance.
If you try to describe the concept of current strength in simple words, it is best to imagine the flow of cars passing through the tunnel. The cars are the electrons, and the tunnel is the wire. The more cars pass at one time through the cross section of the tunnel, the greater the current strength, which is measured by a device called an "ammeter" in Amperes (A), and in the formulas it is indicated by the letter (I).
Voltage is a relative value expressing the difference in the charges of the bodies between which the current flows. If one object has a very high charge and the other is very low, then there will be a high voltage between them, which is measured using a voltmeter device and units called Volts (V). In formulas, it is identified by the letter (U).
Resistance characterizes the ability of a conductor, conditionally a copper wire, to pass a certain amount of current through itself, that is, electrons. A resistive conductor generates heat by expending part of the energy of the current passing through it, thereby reducing its strength. Resistance is calculated in Ohms (Ohm), and the letter (R) is used in the formulas.
Formulas for calculating current characteristics
Applying three physical quantities, you can calculate the characteristics of the current using Ohm's Law. It is expressed by the formula:
Where I is the current strength, U is the voltage in the circuit section, R is the resistance.
From the formula, we see that the current strength is calculated by dividing the voltage value by the resistance value. Hence we have the formulation of the law:
The current is directly proportional to the voltage and inversely proportional to the resistance of the conductor.
From this formula, mathematically, you can calculate its other components.
Resistance:
Voltage:
It is important to note that the formula is valid only for a specific section of the chain. For a complete, closed circuit, as well as other special cases, there are other Ohm's laws.
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Effect of current on different materials and living beings
Various chemical elements under the influence of current behave differently. Some superconductors offer no resistance to electrons moving through them, causing no chemical reaction. Metals, on the other hand, with excessive voltage for them, can collapse, melt. Dielectrics that do not pass current do not enter into any interaction with it at all and thereby protect against it. environment. This phenomenon is successfully used by a person when insulating wires with rubber.
For living organisms, the current is an ambiguous phenomenon. It can have both beneficial and destructive effects. Humans have long used controlled shocks for therapeutic purposes, from mild brain-stimulating shocks to powerful electric shocks that can start a stopped heart and bring a person back to life. A strong discharge can lead to serious health problems, burns, tissue death and even instant death. When working with electrical appliances, you must follow the safety rules.
In nature, you can find many phenomena in which electricity plays a key role: from deep-sea creatures (electric stingray) that can shock, to lightning during a thunderstorm. Man has been mastering this natural force for a long time and skillfully uses it, thanks to which all modern electronics work.
It should be remembered that natural phenomena can be both beneficial and harmful to humans. Studying from school and further education helps people to competently use the phenomena of the world for the benefit of society.
Without a certain initial knowledge of electricity, it’s hard to imagine how electrical appliances work, why they work at all, why you need to plug in the TV to make it work, and a small battery is enough for a flashlight to shine in the dark.
And so we will understand everything in order.
Electricity
Electricity is a natural phenomenon that confirms the existence, interaction and movement of electric charges. Electricity was first discovered as early as the 7th century BC. Greek philosopher Thales. Thales drew attention to the fact that if a piece of amber is rubbed against wool, it begins to attract light objects to itself. Amber in ancient Greek is electron.
This is how I imagine Thales sitting, rubbing a piece of amber on his himation (this is the woolen outerwear of the ancient Greeks), and then, with a puzzled look, looks at how hair, scraps of thread, feathers and scraps of paper are attracted to amber.
This phenomenon is called static electricity. You can repeat this experience. To do this, thoroughly rub a regular plastic ruler with a woolen cloth and bring it to small pieces of paper.
It should be noted that this phenomenon has not been studied for a long time. And only in 1600, in his essay "On the Magnet, Magnetic Bodies, and the Great Magnet - the Earth", the English naturalist William Gilbert introduced the term - electricity. In his work, he described his experiments with electrified objects, and also established that other substances can become electrified.
Further, over the course of three centuries, the most advanced scientists of the world explore electricity, write treatises, formulate laws, invent electrical machines, and only in 1897 Joseph Thomson discovers the first material carrier of electricity - an electron, a particle, due to which electrical processes in substances are possible.
Electron is an elementary particle, has a negative charge approximately equal to -1.602 10 -19 Cl (Pendant). Denoted e or e -.
Voltage
To make charged particles move from one pole to another, it is necessary to create between the poles potential difference or - Voltage. Voltage unit - Volt (AT or V). In formulas and calculations, stress is indicated by the letter V . To get a voltage of 1 V, you need to transfer a charge of 1 C between the poles, while doing work of 1 J (Joule).
For clarity, imagine a tank of water located at a certain height. A pipe comes out of the tank. Water under natural pressure leaves the tank through a pipe. Let's agree that water is electric charge, the height of the water column (pressure) is voltage, and the speed of the water flow is electricity.
Thus, the more water in the tank, the higher the pressure. Similarly, from an electrical point of view, the greater the charge, the higher the voltage.
We begin to drain the water, while the pressure will decrease. Those. the charge level drops - the voltage value decreases. This phenomenon can be observed in a flashlight, the light bulb shines dimmer as the batteries run out. Note that the lower the water pressure (voltage), the lower the water flow (current).
Electricity
Electricity- this is a physical process of directed movement of charged particles under the influence of an electromagnetic field from one pole of a closed electrical circuit to another. Charge-transporting particles can be electrons, protons, ions, and holes. In the absence of a closed circuit, current is not possible. Particles capable of carrying electric charges do not exist in all substances, those in which they exist are called conductors and semiconductors. And substances in which there are no such particles - dielectrics.
Unit of measurement of current strength - Ampere (BUT). In formulas and calculations, the current strength is indicated by the letter I . A current of 1 Ampere is formed when a charge of 1 Coulomb (6.241 10 18 electrons) passes through a point in the electrical circuit in 1 second.
Let's go back to our water-electricity analogy. Only now let's take two tanks and fill them with an equal amount of water. The difference between the tanks is in the diameter of the outlet pipe.
Let's open the taps and make sure that the flow of water from the left tank is greater (the pipe diameter is larger) than from the right one. This experience is a clear proof of the dependence of the flow rate on the diameter of the pipe. Now let's try to equalize the two streams. To do this, add water to the right tank (charge). This will give more pressure (voltage) and increase the flow rate (current). In an electrical circuit, the pipe diameter is resistance.
The conducted experiments clearly demonstrate the relationship between tension, current and resistance. We'll talk more about resistance a little later, and now a few more words about the properties of electric current.
If the voltage does not change its polarity, plus to minus, and the current flows in one direction, then this is D.C. and correspondingly constant pressure. If the voltage source changes its polarity and the current flows in one direction, then in the other - this is already alternating current and AC voltage. Maximum and minimum values (marked on the graph as io ) - this is amplitude or peak currents. In household outlets, the voltage changes its polarity 50 times per second, i.e. the current oscillates back and forth, it turns out that the frequency of these oscillations is 50 Hertz, or 50 Hz for short. In some countries, such as the USA, the frequency is 60 Hz.
Resistance
Electrical resistance- a physical quantity that determines the property of the conductor to prevent (resist) the passage of current. Resistance unit - Ohm(denoted Ohm or the Greek letter omega Ω ). In formulas and calculations, resistance is indicated by the letter R . A conductor has a resistance of 1 ohm, to the poles of which a voltage of 1 V is applied and a current of 1 A flows.
Conductors conduct current differently. Them conductivity depends, first of all, on the material of the conductor, as well as on the cross section and length. The larger the cross section, the higher the conductivity, but the longer the length, the lower the conductivity. Resistance is the inverse of conduction.
On the example of a plumbing model, the resistance can be represented as the diameter of the pipe. The smaller it is, the worse the conductivity and the higher the resistance.
The resistance of the conductor is manifested, for example, in the heating of the conductor when current flows in it. Moreover, the greater the current and the smaller the cross section of the conductor, the stronger the heating.
Power
Electric power is a physical quantity that determines the rate of electricity conversion. For example, you have heard more than once: "a light bulb for so many watts." This is the power consumed by the light bulb per unit of time during operation, i.e. converting one form of energy into another at a certain rate.
Sources of electricity, such as generators, are also characterized by power, but already generated per unit of time.
Power unit - Watt(denoted Tue or W). In formulas and calculations, power is indicated by the letter P . For AC circuits, the term is used Full power, unit - Volt-ampere (V A or VA), denoted by the letter S .
And finally about electrical circuit. This circuit is a set of electrical components capable of conducting electric current and connected to each other in an appropriate way.
What we see in this image is an elementary electrical appliance (flashlight). under tension U(C) a source of electricity (batteries) through conductors and other components with different resistances 4.59 (237 Votes)
At today's meeting, we will talk about electricity, which has become an integral part of modern civilization. The power industry has invaded every area of our lives. And the presence in every home of household appliances that use electric current is so natural and integral part of life that we take it for granted.
So, the attention of our readers is offered basic information about the electric current.
What is electric current
By electric current is meant directed motion of charged particles. Substances containing a sufficient amount of free charges are called conductors. And the totality of all devices interconnected by means of wires is called an electrical circuit.
AT Everyday life we use electricity passing through metal conductors. The charge carriers in them are free electrons.
Usually they rush randomly between atoms, but the electric field forces them to move in a certain direction.
How does this happen
The flow of electrons in a circuit can be compared to the flow of water falling from high level to low. The role of the level in electrical circuits is played by the potential.
For the current to flow in the circuit, a constant potential difference must be maintained at its ends, i.e. voltage.
It is usually denoted by the letter U and measured in volts (B).
Due to the applied voltage, an electric field is established in the circuit, which gives the electrons a directed movement. The higher the voltage, the stronger the electric field, and hence the intensity of the flow of directionally moving electrons.
The speed of propagation of the electric current is equal to the speed at which the electric field is established in the circuit, i.e., 300,000 km/s, but the speed of the electrons barely reaches only a few mm per second.
It is generally accepted that the current flows from a point with a large potential, i.e. from (+) to a point with a lower potential, i.e. to (-). The voltage in the circuit is maintained by a current source, such as a battery. The sign (+) at its end means a lack of electrons, the sign (-) their excess, since electrons are carriers of precisely a negative charge. As soon as the circuit with the current source becomes closed, the electrons rush from the place where they are in excess to the positive pole of the current source. Their path runs through wires, consumers, measuring instruments and other circuit elements.
Note that the direction of the current is opposite to the direction of the electrons.
Just the direction of the current, by agreement of scientists, was determined before the nature of the current in metals was established.
Some quantities characterizing the electric current
Current strength. The electric charge passing through the cross section of the conductor in 1 second is called the current strength. For its designation, the letter I is used, measured in amperes (A).
Resistance. The next value to be aware of is resistance. It arises due to collisions of directionally moving electrons with ions crystal lattice. As a result of such collisions, electrons transfer part of their kinetic energy to ions. As a result, the conductor heats up, and the current decreases. Resistance is denoted by the letter R and is measured in ohms (Ohm).
The resistance of a metal conductor is the greater, the longer the conductor and the smaller its cross-sectional area. With the same length and diameter of the wire, conductors made of silver, copper, gold and aluminum have the least resistance. For obvious reasons, aluminum and copper wires are used in practice.
Power. Performing calculations for electrical circuits, sometimes you need to determine the power consumption (P).
To do this, the current flowing through the circuit should be multiplied by the voltage.
The unit of measure for power is the watt (W).
Direct and alternating current
The current given by a variety of batteries and accumulators is constant. This means that the strength of the current in such a circuit can only be changed in magnitude by changing its resistance in various ways, while its direction remains unchanged.
But most household appliances consume alternating current, i.e., the current, the magnitude and direction of which is continuously changing according to a certain law.
It is produced in power plants and then transported through high-voltage transmission lines to our homes and businesses.
In most countries, the frequency of current reversal is 50 Hz, i.e. occurs 50 times per second. In this case, each time the current strength gradually increases, reaches a maximum, then decreases to 0. Then this process is repeated, but with the opposite direction of the current.
In the US, all appliances operate at 60 Hz. An interesting situation has developed in Japan. There, one third of the country uses alternating current with a frequency of 60 Hz, and the rest - 50 Hz.
Caution - electricity
Electric shocks can be caused by using electrical appliances and from lightning strikes because The human body is a good conductor of electricity. Often, electrical injuries are received by stepping on a wire lying on the ground or pushing away dangling electrical wires with your hands.
Voltage over 36 V is considered dangerous for humans. If a current of only 0.05 A passes through the human body, it can cause involuntary muscle contraction, which will not allow the person to independently break away from the source of damage. A current of 0.1 A is lethal.
Alternating current is even more dangerous, because it has a stronger effect on a person. This friend and helper of ours in a number of cases turns into a merciless enemy, causing a violation of breathing and heart function, up to its complete stop. It leaves terrible marks on the body in the form of severe burns.
How to help the victim? First of all, turn off the source of damage. And then take care of first aid.
Our acquaintance with electricity is coming to an end. Let's add just a few words about marine life with "electric weapons". These are some types of fish, sea eel and stingray. The most dangerous of them is sea eel.
Do not swim to him at a distance of less than 3 meters. His blow is not fatal, but consciousness can be lost.
If this message was useful to you, I would be glad to see you
". Today I want to touch on such a topic as electric current. What is it? Let's try to remember school curriculum.
Electric current is the ordered movement of charged particles in a conductor.
If you remember, in order for charged particles to move, (an electric current arises) you need to create an electric field. To create an electric field, you can carry out such elementary experiments as rubbing a plastic handle on wool and for some time it will attract light objects. Bodies capable of attracting objects after rubbing are called electrified. We can say that the body in this state has electric charges, and the bodies themselves are called charged. From the school curriculum, we know that all bodies are made up of tiny particles (molecules). A molecule is a particle of a substance that can be separated from a body and it will have all the properties inherent in this body. Molecules of complex bodies are formed from various combinations of atoms of simple bodies. For example, a water molecule consists of two simple ones: an oxygen atom and one hydrogen atom.
Atoms, neutrons, protons and electrons - what are they?
In turn, an atom consists of a nucleus and revolving around it 
electrons. Each electron in an atom has a small electrical charge. For example, a hydrogen atom consists of a nucleus of an electron revolving around it. 
The nucleus of an atom consists, in turn, of protons and neutrons. The nucleus of an atom, in turn, has an electric charge. The protons that make up the nucleus have the same electric charges and electrons. But protons, unlike electrons, are inactive, but their mass is many times greater than the mass of an electron. 
The particle neutron, which is part of the atom, has no electric charge, it is neutral. The electrons that revolve around the nucleus of an atom and the protons that make up the nucleus are carriers of equal electric charges. Between the electron and the proton there is always a force of mutual attraction, and between the electrons themselves and between the protons, the force of mutual repulsion. Because of this, the electron has a negative electric charge, and the proton positive. From this we can conclude that there are 2 kinds of electricity: positive and negative. The presence of equally charged particles in an atom leads to the fact that between the positively charged nucleus of the atom and the electrons rotating around it, there are forces of mutual attraction that hold the atom together. Atoms differ from each other in the number of neutrons and protons in the nuclei, which is why the positive charge of the nuclei of atoms is not the same various substances. In atoms of different substances, the number of rotating electrons is not the same and is determined by the positive charge of the nucleus. The atoms of some substances are firmly bound to the nucleus, while in others this bond can be much weaker. This explains the different strengths of the bodies. Steel wire is much stronger than copper wire, which means that steel particles are more strongly attracted to each other than copper particles. The attraction between molecules is especially noticeable when they are close to each other. Most a prime example Two drops of water merge into one on contact.
Electric charge
In the atom 
of any substance, the number of electrons revolving around the nucleus is equal to the number of protons contained in the nucleus. The electric charge of an electron and a proton are equal in magnitude, which means that the negative charge of the electrons is equal to the positive charge of the nucleus. These charges mutually balance each other, and the atom remains neutral. In an atom, electrons create an electron shell around the nucleus. The electron shell and the nucleus of an atom are in continuous oscillatory motion. When the atoms move, they collide with each other and one or more electrons fly out of them. The atom ceases to be neutral and becomes positively charged. Since its positive charge has become more negative (weak connection between the electron and the nucleus - metal and coal). In other bodies (wood and glass), the electronic shells are not broken. After breaking away from atoms, free electrons move randomly and can be captured by other atoms. The process of appearances and disappearances in the body is continuous. As the temperature increases, the speed of the vibrational movement of atoms increases, the collisions become more frequent, become stronger, the number of free electrons increases. However, the body remains electrically neutral, since the number of electrons and protons in the body does not change. If a certain amount of free electrons is removed from the body, then the positive charge becomes greater than the total charge. The body will be positively charged and vice versa. If a lack of electrons is created in the body, then it is additionally charged. If the excess is negative. The greater this deficiency or excess, the greater the electric charge. In the first case (more positively charged particles), bodies are called conductors (metals, aqueous solutions of salts and acids), and in the second (lack of electrons, negatively charged particles) dielectrics or insulators (amber, quartz, ebonite). For the continuous existence of an electric current, it is necessary to constantly maintain a potential difference in the conductor.
Well, that's a little physics course is over. I think you, with my help, remembered the school curriculum for the 7th grade, and we will analyze what the potential difference is in my next article. Until we meet again on the pages of the site.
