At today's meeting we will talk about electricity, which has become an integral part of modern civilization. Electric power has invaded all areas of our lives. And the presence in every home of household appliances that use electric current is such a natural and integral part of everyday life that we take it for granted.
So, our readers are offered basic information about electric current.
What is electric current
Electric current means directed movement of charged particles. Substances containing a sufficient number of free charges are called conductors. A collection of all devices connected to each other using wires is called an electrical circuit.
IN everyday life we use electricity passing through metal conductors. The charge carriers in them are free electrons.
Usually they rush chaotically between atoms, but the electric field forces them to move in a certain direction.
How it happens
The flow of electrons in a circuit can be compared to the flow of water falling from high level to low. The role of level in electrical circuits is played by potential.
For 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 directional movement. The higher the voltage, the stronger the electric field, and therefore the intensity of the flow of directionally moving electrons.
The speed of propagation of electric current is equal to the speed of establishment of an electric field in the circuit, i.e. 300,000 km/s, but the speed of electrons barely reaches only a few mm per second.
It is generally accepted that current flows from a point with a higher 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 (−) means their excess, since electrons are carriers of a negative charge. As soon as the circuit with the current source becomes closed, electrons rush from the place where there is an excess of them to the positive pole of the current source. Their path runs through wires, consumers, measuring instruments and other circuit elements.
Please note that the direction of the current is opposite to the direction of movement of the electrons.
Simply, the direction of the current, by agreement of scientists, was determined before the nature of the current in metals was established.
Some quantities characterizing electric current
Current strength. The electric charge passing through the cross-section of a conductor in 1 second is called current strength. The letter I is used to designate it and is measured in amperes (A).
Resistance. The next quantity you need to know about is resistance. It arises due to collisions of directionally moving electrons with ions of the crystal lattice. As a result of such collisions, electrons transfer part of their kinetic energy to the ions. As a result, the conductor heats up and the current strength decreases. Resistance is symbolized by the letter R and is measured in ohms (ohms).
The longer the conductor and the smaller its cross-sectional area, the greater the resistance of a metal conductor. With the same length and diameter of the wire, conductors made of silver, copper, gold and aluminum have the least resistance. For obvious reasons, wires made of aluminum and copper are used in practice.
Power. When performing calculations for electrical circuits, it is sometimes necessary to determine the power consumption (P).
To do this, the current flowing through the circuit must be multiplied by the voltage.
The unit of power is the watt (W).
Direct and alternating current
The current provided by various batteries and accumulators is constant. This means that the current strength in such a circuit can only be changed in magnitude by changing in various ways its resistance, and its direction remains unchanged.
But Most electrical appliances consume alternating current, that is, a current whose magnitude and direction continuously changes according to a certain law.
It is generated in power plants and then travels through high-voltage transmission lines into our homes and businesses.
In most countries, the frequency of change in current direction is 50 Hz, that is, it 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 USA, all devices operate at a frequency of 60 Hz. Interesting situation 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 shock can occur when using electrical appliances and from lightning strikes, since The human body is a good conductor of current. Electrical injuries are often caused by stepping on a wire lying on the ground or pushing away loose electrical wires with your hands.
Voltage above 36 V is considered dangerous to humans. If a current of only 0.05 A passes through a person’s body, it can cause involuntary muscle contraction, which will not allow the person to independently tear himself away from the source of the lesion. A current of 0.1 A is lethal.
Alternating current is even more dangerous because it has a more strong impact per person. This friend and helper of ours in some cases turns into a merciless enemy, causing breathing problems and heart function, even to the point of complete cardiac arrest. 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 providing first aid.
Our acquaintance with electricity is coming to an end. Let's add just a few words about sea creatures, possessing “electric weapons”. These are some types of fish, conger eel and stingray. The most dangerous of them is the conger eel.
You should not swim within 3 meters of it. His blow is not fatal, but consciousness can be lost.
If this message was useful to you, I would be glad to see you
Current and voltage are quantitative parameters used in electrical diagrams. Most often, these quantities change over time, otherwise there would be no point in the operation of the electrical circuit.
Voltage
Conventionally, voltage is indicated by the letter "U". The work expended in moving a unit of charge from a point of low potential to a point of high potential is the voltage between those two points. In other words, it is the energy released after a unit of charge moves from high to low potential.
Voltage can also be called potential difference, as well as electromotive force. This parameter is measured in volts. To move 1 coulomb of charge between two points that have a voltage of 1 volt, 1 joule of work must be done. Coulombs are measured electric charges. 1 coulomb is equal to the charge of 6x10 18 electrons.
Voltage is divided into several types, depending on the types of current.
- Constant voltage . It is present in electrostatic and direct current circuits.
- AC voltage
. This type of voltage is found in circuits with sinusoidal and alternating currents. In the case of sinusoidal current, the following voltage characteristics are considered:
amplitude of voltage fluctuations– this is its maximum deviation from the x-axis;
instantaneous voltage, which is expressed at a certain point in time;
effective voltage, is determined by the active work performed in the 1st half-cycle;
average rectified voltage, determined by the absolute value of the rectified voltage over one harmonic period.
When transmitting electricity through overhead lines, the design 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 the ground and each phase is phase voltage . This rule applies to all types of overhead lines. In Russia, in household electrical networks, the standard is three-phase voltage with a linear voltage of 380 volts and a phase voltage of 220 volts.
Electric current
Current in an electrical circuit is the speed of movement of electrons at a certain point, measured in amperes, and denoted in diagrams by the letter “ I" Derived units of ampere with the corresponding prefixes milli-, micro-, nano, etc. are also used. A current of 1 ampere is generated by moving a unit of charge of 1 coulomb in 1 second.
It is conventionally considered that the current flows in the direction from positive potential to negative. However, from the physics course we know that the electron moves in the opposite direction.
You need to know that voltage is measured between 2 points on the circuit, and current flows through one specific point in the circuit, or through its element. Therefore, if someone uses the expression “tension 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 the ground and this point.
Voltage is generated from exposure to electrical charges in generators and other devices. Current is created by applying a voltage to two points on 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 elements of the circuit have their own voltage value.
Current and voltage obey the rules:
- The sum of currents entering a point is equal to the sum of currents leaving the point (charge conservation rule). This rule is Kirchhoff's law for current. The point of entry and exit of the current in this case is called a node. A corollary of this law is the following statement: in a series electrical circuit of a group of elements, the current value is the same for all points.
- IN parallel circuit elements, the voltage on all elements is the same. In other words, the sum of the voltage drops in a closed circuit is zero. This Kirchhoff law applies to stresses.
- The work done per unit time by a circuit (power) is expressed as follows: P = 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, spent on performing mechanical work (in electric motors), and converted into radiation various types, accumulates in containers or batteries. When designing complex electrical systems, one of the challenges is the thermal load of the system.
Characteristics of electric current
A prerequisite for the existence of current in an electrical circuit is a closed circuit. If the circuit is broken, the current stops.
Everyone in electrical engineering operates on this principle. They break the electrical circuit with movable mechanical contacts, and thereby stop 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 busbars and other parts that conduct current.
There are also other ways to create 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 of conductors (not superconductors).
- Application of potential difference to charge carriers.
- A chemical reaction that releases new substances.
- The effect of a magnetic field on a conductor.
Current Waveforms
- Straight line.
- Variable harmonic sine wave.
- A meander, similar to a sine wave, but having sharp corners(sometimes the corners may be smoothed).
- A pulsating form of one direction, with an amplitude varying from zero to the greatest value according to a certain law.
Types of work of electric current
- Light radiation created by lighting devices.
- Generating heat using heating elements.
- Mechanical work (rotation of electric motors, operation of other electrical devices).
- Creation of electromagnetic radiation.
Negative phenomena caused by electric current
- Overheating of contacts and live parts.
- The occurrence of eddy currents in the cores of electrical devices.
- Electromagnetic radiation into the external environment.
When designing, creators of electrical devices and various circuits must take into account the above properties of electric current in their designs. For example, the harmful effects of eddy currents in electric motors, transformers and generators are reduced by fusion of the cores used to pass magnetic fluxes. Lamination of the core is its production not from a single piece of metal, but from a set of individual thin plates of special electrical steel.
But, on the other hand, eddy currents are used to operate microwave ovens and ovens operating on the principle of magnetic induction. Therefore, we can say that eddy currents are not only harmful, but also beneficial.
Alternating current with a signal in the form of a sinusoid can differ in frequency of oscillations per unit time. In our country, the industrial frequency of electrical current is standard and equal to 50 hertz. In some countries, a current frequency of 60 hertz is used.
For various purposes in electrical engineering and radio engineering, other frequency values are used:
- Low frequency signals with a lower current frequency.
- High frequency signals that are much higher than the frequency of industrial current.
It is believed that electric current arises from the movement of electrons within a conductor, which is why 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 when subjected to a constant force is compared to a parachutist descending 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 movement of electrons is affected by the force of the electric field, and the ions of the crystal lattices resist this movement. Average speed electrons reaches a constant value, as does the speed of the parachutist.
In a metal conductor, the speed of movement of one electron is 0.1 mm per second, and the speed of electric current is about 300 thousand km per second. This is because electric current only flows where voltage is applied to charged particles. Therefore it is achieved high speed current flow.
When electrons move in a crystal lattice, the following pattern exists. Electrons do not collide with all oncoming ions, 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 hampered by large ions that offer resistance. This is especially noticeable when metals are heated, when heavy ions “sway”, increase in size and reduce the electrical conductivity of the conductor crystal lattices. Therefore, when metals are heated, their resistance always increases. As the temperature decreases, the electrical conductivity increases. When the metal temperature drops to absolute zero superconductivity effect can be achieved.
The first discoveries related to the work of electricity began in the 7th century BC. Philosopher Ancient Greece Thales of Miletus discovered that when amber is rubbed on wool, it is subsequently able to attract lightweight objects. “Electricity” is translated from Greek as “amber.” In 1820, André-Marie Ampère established the law of direct current. Subsequently, the magnitude of the current, or what the electric current is measured in, began to be denoted in amperes.
Meaning of the term
The concept of electric current can be found in any physics textbook. Electric current- this is the ordered movement of electrically charged particles in a direction. To understand to the common man what electric current is, you should use an electrician’s dictionary. In it, the term stands for the movement of electrons through a conductor or ions through an electrolyte.
Depending on the movement of electrons or ions inside a conductor, the following are distinguished: 
types of currents:
- constant;
- variable;
- periodic or pulsating.
Basic measurement quantities
Electric current strength- the main indicator that electricians use in their work. The strength of the electric current depends on the amount of charge that flows through the electrical circuit over a set period of time. The greater the number of electrons flowing from one beginning of the source to the end, the greater the charge transferred by the electrons will be.
A quantity that is measured by the ratio of the electric charge flowing through the cross-section of particles in a conductor to the time of its passage. Charge is measured in coulombs, time is measured in seconds, and one unit of electrical flow is determined by the ratio of charge to time (coulomb to second) or amperes. Determination of the electric current (its strength) occurs by sequentially connecting two terminals in the electrical circuit.
When an electric current operates, the movement of charged particles is accomplished using an electric field and depends on the force of electron movement. The value on which the work of an electric current depends is called voltage and is determined by the ratio of the work of the current in a specific part of the circuit and the charge passing through the same part. The unit of measurement volts is measured by a voltmeter when two terminals of the device are connected to a circuit in parallel.
The amount of electrical resistance is directly dependent on the type of conductor used, its length and cross-section. It is measured in ohms.
Power is determined by the ratio of the work done by the movement of currents to the time when this work occurred. Power is measured in watts.
A physical quantity such as capacitance is determined by the ratio of the charge of one conductor to the potential difference between the same conductor and the neighboring one. The lower the voltage when conductors receive an electrical charge, the greater their capacity. It is measured in farads.
The amount of work done by electricity at a certain interval in the chain is found using the product of current, voltage and the time period during which the work was carried out. The latter is measured in joules. The operation of electric current is determined using a meter that connects the readings of all quantities, namely voltage, force and time.
Electrical Safety Techniques
Knowledge of electrical safety rules will help prevent emergency situations and protect human health and life. Since electricity tends to heat the conductor, there is always the possibility of a situation dangerous to health and life. To ensure safety at home must be adhered to the following simple but important rules:
- Network insulation must always be in good condition to avoid overloads or the possibility of short circuits.
- Moisture should not get on electrical appliances, wires, panels, etc. Also, a humid environment provokes short circuits.
- Be sure to ground all electrical devices.
- Overloading electrical wiring must be avoided as there is a risk of the wires catching fire.
Safety precautions when working with electricity involve the use of rubberized gloves, mittens, mats, discharge devices, grounding devices for work areas, circuit breakers or fuses with thermal and current protection.
Experienced electricians, when there is a possibility of electric shock, work with one hand, and the other is in their pocket. In this way, the hand-to-hand circuit is interrupted in the event of an involuntary touch to the shield or other grounded equipment. If equipment connected to the network catches fire, extinguish the fire exclusively with powder or carbon dioxide extinguishers.
Application of electric current
Electric current has many properties that allow it to be used in almost all areas of human activity. Ways to use electric current:
Electricity today is the most environmentally friendly clean look energy. In conditions modern economy the development of the electric power industry has planetary significance. In the future, if there is a shortage of raw materials, electricity will take a leading position as an inexhaustible source of energy.
When a person learned to create and use electric current, his quality of 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 electric current is.
What is current
The definition of electric current is its representation in the form of a directed flow of moving carrier particles, positively or negatively charged. Charge carriers can be:
- electrons charged with a minus sign moving in metals;
- ions in liquids or gases;
- positively charged holes from moving electrons in semiconductors.
What current is is also determined by the presence of an electric field. Without it, a directed flow of charged particles will not arise.
The concept of electric currentIt would be incomplete without listing its manifestations:
- Any electric current is accompanied by a magnetic field;
- The conductors heat up as it passes;
- 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:
- Metal conductors contain free electrons that begin to move under the influence of an electric field. When the temperature increases, the resistance of the conductors also increases, since heat increases the movement of atoms in a chaotic order, which interferes with free electrons;
- In a liquid medium formed by electrolytes, the resulting electric field causes a 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;
Important! The electrolyte may be solid, but the nature of the current flow in it is identical to liquid.
- The gaseous medium is also characterized by the presence of ions that come into motion. Plasma is formed. Radiation also produces free electrons that participate in directed motion;
- When an electric current is created in a vacuum, the electrons released at the negative electrode move towards the positive electrode;
- In semiconductors, there are free electrons that break bonds when heated. In their places there remain holes with a charge with a “plus” sign. Holes and electrons are capable of creating directed motion.
Non-conducting 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
- Constant. It is characterized by a constant quantitative value of the current and direction;
- Variable. Over time, it periodically changes its characteristics. It is divided into several varieties, depending on the parameter being changed. Mainly the quantitative value of the current and its direction vary along a sinusoid;
- Eddy currents. Occur when the magnetic flux undergoes changes. Form closed circuits without moving between poles. Eddy currents cause intense heat generation, and as a result, losses increase. In the cores of electromagnetic coils, they are limited by using a design of individual insulated plates instead of a solid one.
Electrical characteristics
- Current strength. This is a quantitative measurement of the charge passing per unit of time across a cross-section of conductors. Charges are measured in coulombs (C), the time unit is second. Current strength is C/s. The resulting ratio was called ampere (A), which measures the quantitative value of the current. The measuring device is an ammeter, connected in series to the electrical connection circuit;
- Power. The electric current in the conductor must overcome the resistance of the medium. The work expended to overcome it over a certain period of time will be power. In this case, electricity is converted into other types of energy - work is done. Power depends on current and voltage. Their product will determine the active power. When multiplied by time, the energy consumption is obtained - what the meter shows. Power can be measured in volt-amperes (VA, kVA, mVA) or in watts (W, kW, mW);
- Voltage. One of the three most important characteristics. For current to flow, it is necessary to create a potential difference between two points in a closed circuit of electrical connections. Voltage is characterized by the work done by an electric field when a single charge carrier moves. 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;
- Resistance. Characterizes the ability of conductors to pass electric current. Determined by the conductor material, length and cross-sectional area. Measurement is in ohms (Ohm).
Laws for electric current
Electrical circuits are calculated using three main laws:
- Ohm's law. It was studied and formulated by a physicist from Germany 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. Almost any electrical circuit is calculated based on Ohm's law. Basic formula: I = U/R, or current is directly proportional to voltage and inversely proportional to resistance;
- 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 EMF (electromotive force) in a closed loop. The magnitude of the induced emf, measured in volts, is proportional to the rate at which the magnetic flux changes. Thanks to the law of induction, generators produce electricity;
- Joule-Lenz law. It is important when calculating the heating of conductors, which is used for the design and manufacture of heating, lighting devices, and other electrical equipment. The law allows us to determine the amount of heat released during the passage of electric current:
where I is the strength of the flowing current, R is the resistance, t is time.
Electricity in the atmosphere
An electric field may exist in the atmosphere, and 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 be designated earth's surface and the ionosphere, between which a dielectric - air - circulates.
Types of atmospheric electricity:
- Lightning discharges. Lightning with a visible glow and thunderclaps. Lightning voltage reaches hundreds of millions of volts at a current of 500,000 A;
- St. Elmo's Fire. Corona discharge of electricity formed around wires, masts;
- Ball lightning. A ball-shaped discharge moving through the air;
- Polar lights. Multicolor glow of the earth's ionosphere under the influence of charged particles penetrating from space.
Used by man beneficial properties electric current in all areas of life:
- lighting;
- signal transmission: telephone, radio, television, telegraph;
- electric transport: trains, electric cars, trams, trolleybuses;
- creating a comfortable microclimate: heating and air conditioning;
- medical equipment;
- household use: electrical appliances;
- computers and mobile devices;
- industry: machines and equipment;
- electrolysis: production of aluminum, zinc, magnesium and other substances.
Electrical Hazard
Direct contact with electric current without protective equipment is deadly to humans. Several types of impacts are possible:
- thermal burn;
- electrolytic breakdown of blood and lymph with a change in its composition;
- convulsive muscle contractions can provoke cardiac fibrillation until it stops completely, and disrupt the functioning of the respiratory system.
Important! The current felt by a person begins with a value of 1 mA; if the current value is 25 mA, serious negative changes in the body are possible.
The most main characteristic electric current - it can perform useful work for a person: to light the house, wash and dry clothes, cook dinner, heat the home. Nowadays, its use in information transmission occupies a significant place, although this does not require a lot of energy consumption.
Video
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 structure and operation of electric current. So, let's figure out what work and current power are.
Where does electric current even come from?
Despite the apparent simplicity of the question, few are able to give an intelligible answer to it. Of course, these days, when technology is developing at an incredible speed, people don’t really think about such basic things as the principle of operation of electric current. Where does electricity come from? Surely many will answer, “Well, out of the socket, of course,” or simply shrug their shoulders. Meanwhile, it is very important to understand how current works. This should be known not only to scientists, but also to people who are in no way connected with the world of science, for their overall diversified development. But not everyone can competently use the operating principle of current.
So, first you should understand that electricity does not appear out of nowhere: it is produced by special generators that are located at various power plants. Thanks to the rotation of turbine blades, steam produced by heating water with coal or oil produces energy, which is subsequently converted into electricity with the help of a generator. The design of the generator is very simple: in the center of the device there is a huge and very strong magnet, which forces electrical charges to move along copper wires.
How does electric current reach our homes?
After a certain amount of electric current has been generated using energy (thermal or nuclear), it can be supplied to people. This supply of electricity works as follows: in order for electricity to successfully reach all apartments and businesses, it needs to be “push.” And for this you will need to increase the force that will do this. It is called electric current voltage. The principle of operation is as follows: current passes through a transformer, which increases its voltage. Next, the electric current flows through cables installed deep underground or at a height (because the voltage sometimes reaches 10,000 Volts, which is deadly to humans). When the current reaches its destination, it must again pass through the transformer, which will now reduce its voltage. Then it passes through the wires to the installed switchboards in apartment buildings or other buildings.
The electricity carried through the wires can be used thanks to a system of sockets, connecting household appliances to them. There are additional wires in the walls through which electric current flows, and it is thanks to this that the lighting and all the equipment in the house work.
What is current work?
The energy carried by electric current is converted over time into light or heat. For example, when we turn on a lamp, the electrical form of energy turns into light.
To put it in simple language, the work of current is the action that electricity itself produces. Moreover, it can be very easily calculated using the formula. Based on the law of conservation of energy, we can conclude that electrical energy has not been lost, it has completely or partially transferred to another form, giving off a certain amount of heat. This heat is the work done by the current when it passes through the conductor and heats it (heat exchange occurs). This is what the Joule-Lenz formula looks like: A = Q = U*I*t (work is equal to the amount of heat or the product of the current power and the time during which it flows through the conductor).
What does direct current mean?
Electric current There are two types: variable and constant. They differ in that the latter does not change its direction, it has two clamps (positive “+” and negative “-”) and always begins its movement from “+”. And alternating current has two terminals - phase and zero. It is precisely because of the presence of one phase at the end of the conductor that it is also called single-phase.
The principles of the design of single-phase alternating and direct electric current are completely different: unlike constant, alternating current changes both its direction (forming a flow both from phase towards zero and from zero towards phase) and its magnitude. For example, alternating current periodically changes the value of its charge. It turns out that at a frequency of 50 Hz (50 vibrations per second), electrons change the direction of their movement exactly 100 times.
Where is DC used?
Direct electric current has some characteristics. Due to the fact that it flows strictly in one direction, it is more difficult to transform it. The following elements can be considered DC sources:
- batteries (both alkaline and acid);
- ordinary batteries used in small devices;
- as well as various devices such as converters.
DC operation
What are its main characteristics? This is work and current power, and both of these concepts are very closely related to each other. Power implies the speed of work per unit of time (per 1 s). According to the Joule-Lenz law, we find that the work done by 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 done to transfer charges along the conductor.
This is the formula for finding the work of current, taking into account Ohm’s law on resistance in conductors: A = I 2 *R*t (work is equal to the square of the current multiplied by the value of the resistance of the conductor and again multiplied by the time during which the work was done).