What does static electricity mean in our life. Types of static electricity

People are constantly faced with static electricity, or rather with its manifestations (in their apartment, in a car, at work, etc.). However, not many of us seriously thought about the nature of its occurrence, physical properties, characteristics, means of protection against static electricity. This article is devoted to finding answers to these questions.

What is static electricity

For a molecule or atom of any substance, the equilibrium state is normal, i.e. the number of positive (protons) and negative (electrons) particles in an atom is the same. But the electrons of a substance can easily (for different materials in different ways) move from one atom to another, thereby forming a positive (missing electron) or negative (excess electron) charge of the atom. It is this imbalance in atoms and molecules that forms a static electric field. Such fields are unstable and discharge at the first opportunity.

GOST 17.1.018-79 “Static electricity. Intrinsically safe" interprets the term "static electricity" as the ability of free electric charges to arise, persist and relax in the volume and on the surface of semiconductors and dielectrics.
An obligatory "companion" of a static field is dry air. At humidity above 80%, such fields almost never form. water is an excellent conductor and does not allow excess electricity to build up on the surface of materials.

Sources of a static field and the reasons for its generation

We all remember from the school physics course the experience with an ebonite rod, or a plastic comb and a piece of woolen cloth. After rubbing the rod with a cloth, it was able to attract finely cut pieces of paper to itself.

Friction between two surfaces is the most common source of a static field. It is not necessary to rub the two materials against each other. A static field can occur with a single contact, for example, in the case of winding / unwinding a fabric tape.

Also, the sources of generating a static field can be:

• Sharp temperature changes;
• High level of radiation.

The static field can be "self-acquired" and "induced", i.e. received from another highly electrified object without direct contact with it. This method of "forced electrification" is called induction.

We are all well aware of the electrical crackling when removing outer clothing or the "electric shock" from the car body. We observe and often experience the effect of static discharges when combing hair, cutting paper, pouring gasoline, etc.

A prerequisite for generating a static electric field is the presence of magnetic fields. Thus, it should be stated that free charges surround us constantly. But this is not enough for a person and he actively uses a huge number of different electrical devices in his daily life and work, thereby only increasing the overall “electrical intensity” of the environment.

Scope of use

Electrostatic devices and devices, the principle of which was based on friction, could not leave the laboratory shelves and classrooms, where they are mainly used as demonstration material.

Attempts to use static fields to generate electric current also did not bring much success. Van der Graaff and Felici generators, which were created in the 30th and 40th years of the last century, also did not find wide application, because. this equipment was quite bulky.

In addition, their operation and maintenance was very expensive.

Very useful in terms of industrial applications, was the discovery of corona discharge, which is widely used in various industries. In particular, with its help, it is possible to purify gases from various impurities and apply paint on a surface of any configuration.

Problems related to static electricity

Today much more attention is paid to problems that are a direct consequence of the accumulated electrostatic stress. Electric shocks of various capacities can affect a person, both at home and at work.

For example, a sweater made of synthetic fabric, as a result of friction with the back of a chair or with the material of outerwear, is able to accumulate a discharge that will “make itself felt” when it is removed. It beats much more powerfully when it touches the car body, which is electrified from friction against the air.

Any electrical device, be it a food processor, a laptop, a computer monitor or a vacuum cleaner, necessarily carries an electrostatic charge, which “willingly” passes into a person upon contact. Such a "transition" may or may not cause pain, but it is definitely harmful to the human body.

Scientists have long proven that exposure to the energy of static electricity is a danger to human health, in particular to the cardiovascular and central nervous system.

Protection

In the previously mentioned GOST, methods of protection against the influence of static fields are considered in detail, the simplest of which is reliable grounding of equipment.

What can be done to protect the premises of a private house and industrial premises from static fields?

Video: how to get rid of static electricity.
https://www.youtube.com/watch?v=ls-hBlqJu9Y

To protect people and high-precision equipment from the effects of static electricity, special screens and other electromechanical devices are used in production. To suppress electrification in liquid polymers, special additives and solvents are used. Widely used as a protection against static electricity in everyday life and in the production of various antistatic agents.

These are chemicals that have a low molecular weight, which allows their molecules to move easily and, in addition to this, react with atmospheric moisture. The combination of these characteristics allows them to disperse the foci of static fields and remove the static stress from a person.

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Subtitles

Hello. In this episode of TranslatorsCafe.com, we're going to talk about electric charge. We will look at examples of static electricity and the history of its study. We will talk about how lightning is formed. We will also discuss the use of static electricity in engineering and medicine and conclude our story with a description of the principles for measuring electric charge and voltage and the instruments that are used for this. Surprisingly, we are exposed to static electricity on a daily basis - when petting our beloved cat, combing our hair or pulling on a synthetic sweater. So we unwittingly become generators of static electricity. We literally bathe in it, because we live in a strong electrostatic field of the Earth. This field arises due to the fact that it is surrounded by the ionosphere, the upper layer of the atmosphere, the layer that is conductive. The ionosphere was formed under the influence of cosmic radiation, mainly from the Sun, and has its own charge. While doing everyday things like heating food, we don’t think at all that we are using static electricity by turning the gas supply valve on an auto-ignition burner or bringing an electric lighter to it. Electric charge is a scalar quantity that determines the ability of a body to be a source of electromagnetic fields and take part in electromagnetic interaction. The unit of charge in the SI system is the pendant (C). 1 pendant is an electric charge passing through the cross section of the conductor at a current strength of 1 A in a time of 1 s. 1 pendant is equivalent to approximately 6.242×10^18 e (e is the proton charge). The electron charge is 1.6021892(46) 10^–19 C. Such a charge is called an elementary electric charge, that is, the minimum charge possessed by charged elementary particles. From childhood, we are instinctively afraid of thunder, although it is absolutely safe in itself - it is simply an acoustic consequence of a formidable lightning strike, which is caused by atmospheric static electricity. The sailors of the times of the sailing fleet fell into awe, watching the lights of St. Elmo on their masts, which are also a manifestation of atmospheric static electricity. People endowed the supreme gods of ancient religions with an inalienable attribute in the form of lightning, whether it be the Greek Zeus, the Roman Jupiter, the Scandinavian Thor or the Russian Perun. Centuries have passed since people first began to be interested in electricity, and we sometimes do not even suspect that scientists, having drawn profound conclusions from the study of static electricity, are saving us from the horrors of fires and explosions. We tamed electrostatics by aiming lightning rods into the sky and equipping fuel trucks with grounding devices that allow electrostatic charges to safely escape into the ground. And, nevertheless, static electricity continues to misbehave, interfering with the reception of radio signals - after all, up to 2000 thunderstorms are raging on Earth at the same time, which generate up to 50 lightning discharges every second. People have been studying static electricity since time immemorial. We owe even the term "electron" to the ancient Greeks, although they meant something different by this - that's what they called amber, which was perfectly electrified by friction. Unfortunately, the science of static electricity has not been without casualties - a Russian scientist of German origin, Georg Wilhelm Richmann, was killed during an experiment by a lightning discharge, which is the most formidable manifestation of atmospheric static electricity. In the first approximation, the mechanism of formation of charges of a thundercloud is in many respects similar to the mechanism of electrification of a comb - in it, electrification by friction occurs in exactly the same way. Ice particles, formed from small droplets of water, cooled due to the transfer of ascending air currents to the upper, colder part of the cloud, collide with each other. Larger pieces of ice are charged negatively, while smaller ones are positively charged. Due to the difference in weight, the ice floes are redistributed in the cloud: large, heavier ones sink to the bottom of the cloud, and lighter, smaller ice floes gather in the upper part of the thundercloud. Although the entire cloud as a whole remains neutral, the lower part of the cloud receives a negative charge, while the upper part receives a positive charge. Like an electrified comb that attracts a balloon due to the induction of an opposite charge on its side closest to the comb, a thundercloud induces a positive charge on the surface of the Earth. As the thundercloud develops, the charges increase, while the field strength between them increases, and when the field strength exceeds the critical value for these weather conditions, an electrical breakdown of the air occurs - a lightning discharge. Mankind is indebted to Benjamin Franklin for the invention of a lightning rod (more precisely, it would be called a lightning rod), which forever saved the population of the Earth from fires caused by lightning entering buildings. By the way, Franklin did not patent his invention, making it available to all mankind. Lightning did not always bring only destruction - the Ural miners determined the location of iron and copper ores precisely by the frequency of lightning strikes at certain points in the area. Among the scientists who devoted their time to studying the phenomena of electrostatics, it is necessary to mention the Englishman Michael Faraday, later one of the founders of electrodynamics, and the Dutchman Peter van Muschenbroek, the inventor of the prototype of the electric capacitor - the famous Leyden jar. Watching DTM, IndyCar or Formula 1 races, we do not even suspect that mechanics are calling pilots to change tires to rain, based on weather radar data. And these data, in turn, are based precisely on the electrical characteristics of the approaching thunderclouds. Electrostatic electricity is our friend and enemy at the same time: radio engineers dislike it, pulling on grounding bracelets when repairing burnt circuit boards as a result of a nearby lightning strike. In this case, as a rule, the input stages of the equipment fail. With faulty grounding equipment, it can cause severe man-made disasters with tragic consequences - fires and explosions of entire factories. However, static electricity comes to the rescue of people with acute heart failure caused by chaotic convulsive contractions of the patient's heart. Its normal operation is restored by passing a small electrostatic discharge using a device called a defibrillator. Such devices can be seen in places where there are a lot of people. The scene of the return of the patient from the other world with the help of a defibrillator is a kind of classic for a movie of a certain genre. It should be noted, however, that movies traditionally show a monitor with no heartbeat signal and an ominous straight line, although in fact, the use of a defibrillator, as a rule, does not help if the patient's heart has completely stopped. It would be useful to recall the need for metallization of aircraft to protect against static electricity, that is, the connection of all metal parts of the aircraft, including the engine, into one electrically integral structure. At the tips of the entire tail of the aircraft, static dischargers are installed to drain static electricity that accumulates during flight due to air friction against the aircraft body. These measures are necessary to protect against interference caused by the discharge of static electricity and to ensure the reliable operation of on-board electronic equipment. And most importantly, scientists have come to the conclusion that we probably owe the appearance of life on Earth to static electricity, or rather its discharges in the form of lightning. In the course of experiments in the middle of the last century, with the passage of electrical discharges through a mixture of gases, close in gas composition to the primary composition of the Earth's atmosphere, one of the amino acids was obtained, which is the "brick" of our life. To tame electrostatics, it is very important to know the potential difference or electrical voltage, for the measurement of which instruments called voltmeters were invented. The 19th-century Italian scientist Alessandro Volta introduced the concept of electrical voltage, after whom this unit is named. At one time, galvanometers were used to measure electrostatic voltage, named after Volta's compatriot Luigi Galvani. Unfortunately, these devices were of the electrodynamic type and introduced distortions into the measurements. Scientists began to systematically study the nature of electrostatics from the time of the work of the 18th century French scientist Charles Augustin de Coulomb. In particular, he introduced the concept of electric charge and discovered the law of interaction of charges. The unit for measuring the amount of electricity, the coulomb, is named after him. True, for the sake of historical justice, it should be noted that years earlier the English scientist Lord Henry Cavendish was engaged in this; unfortunately, he wrote to the table and his works were published by the heirs only 100 years later. The work of predecessors devoted to the laws of electrical interactions enabled the physicists George Green, Carl Friedrich Gauss and Simeon Denis Poisson to create a mathematically elegant theory that we still use today. The main principle in electrostatics is the postulate of an electron - an elementary particle that is part of any atom and is easily separated from it under the influence of external forces. In addition, there are postulates about the repulsion of like charges and the attraction of unlike charges. The first measuring device was the simplest electroscope invented by Coulomb - two sheets of electrically conductive foil placed in a glass container. Since then, measuring instruments have evolved significantly - and now they can measure the difference in units of nanocoulombs. With the help of extremely precise physical instruments, the Russian scientist Abram Ioffe and the American physicist Robert Andrews Milliken, independently of each other and almost at the same time, managed to measure the electric charge of an electron. Nowadays, with the development of digital technologies, ultra-sensitive and high-precision devices with unique characteristics have appeared, which, due to the high input resistance, almost do not introduce distortions into measurements. In addition to measuring voltage, such devices allow you to measure other important characteristics of electrical circuits, such as ohmic resistance and flowing current in a wide measurement range. The most advanced instruments, called multimeters or, in professional jargon, testers, because of their versatility, can also measure AC frequency, capacitor capacitance and test transistors and even measure temperature. As a rule, modern devices have built-in protection that does not allow the device to be damaged if used incorrectly. They are compact, easy to handle and safe to operate - each one goes through a series of precision tests, heavy duty tests and deserves a safety certification. Thank you for your attention! If you liked this video, please don't forget to subscribe to our channel!

Origin

The electrification of dielectrics by friction can occur when two dissimilar substances come into contact due to the difference in atomic and molecular forces (due to the difference in the work of the electron output from materials). In this case, the redistribution of electrons (in liquids and gases also ions) occurs with the formation of electrical layers with equal signs of electric charges on the contacting surfaces. In fact, atoms and molecules of one substance, which have a stronger attraction, tear off electrons from another substance, creating a vortex motion of the ions of the medium in which they are enclosed.

Electric discharges can be formed due to some electrical conductivity of moist air. When the air humidity is more than 85%, static electricity practically does not occur.

Static electricity is understood as a set of phenomena associated with the emergence and relaxation of a free electric charge on the surface, or in the volume of dielectrics, or on insulated conductors.

The formation and accumulation of charges on the processed material is associated with two conditions. First, the contact of the surfaces must occur, as a result of which a double electric layer is formed. Secondly, at least one of the contact surfaces must be made of a dielectric material. The charges will remain on the surface after their separation only if the contact destruction time is less than the charge relaxation time. The latter, to a large extent, determines the magnitude of the charges on the separated surfaces.

A double electric layer is a spatial distribution of electric charges at the boundaries of contact between two phases. Such a distribution of charges is observed at the interface metal-metal, metal-vacuum, metal-gas, metal-semiconductor, metal-dielectric, dielectric-dielectric, liquid-solid, liquid-liquid, liquid-gas.

The main value characterizing the ability to electrify is electrical resistivity of surfaces contacted materials. If the contact surfaces are low resistance, then when separated, the charges drain from them and the separate surfaces carry an insignificant charge. If the resistance is high or the speed of separation of the surfaces is high, then the charges will be conserved.

Consequently, the main factors affecting the electrization of substances are their electrophysical parameters and separation rate.

It is conditionally accepted that when the specific electrical resistance of materials is less than 10 5 Ohm m, charges are not stored and materials are not electrified.

It has been established by experiments that when two dielectrics come into contact (friction), the one that has a higher dielectric constant becomes positively charged, while a material with a lower dielectric constant becomes negatively charged.

Under the discharges of static electricity understand the processes of equalization of charges between individual solids that carry different electrostatic charges. They are usually accompanied by sliding, corona, spark discharge phenomena. Sparks can ignite flammable gases or vapors, or initiate explosive mixtures, and the electromagnetic fields generated by the discharges can damage electronic components, disable or impair the functions of electronic equipment.

Static charges that cause hazardous effects can be generated in a variety of ways. However, in the manufacture and use of electronic elements and devices, two mechanisms of electrization are essential: due to induction and friction.

Charging currents range from hundreds of picoamps to several microamperes, and electrostatic charges range from 3 nC to 5 μC. The electrostatic potential difference between bodies is determined after the end of the charging process by the ratio of the acquired charge Q to the tank C AB bodies to each other:

U AB =Q/C AB .

Rice. 3.11 illustrates the influence of the materials used, as well as the relative humidity of the air, on the amount of voltage that can be obtained by electrification.

Table 3.1. Approximate values ​​of voltages of static charges at a relative humidity of 24% and a temperature of 21 0 С

Electronic parts, elements and devices must be handled with particular care to avoid damage due to electrostatic phenomena.

Of particular importance when handling electronic devices is the possible electrostatic charge of the human body, which gets on switching circuits, printed circuit boards, controls, instrument cases during their transportation, installation, testing, operation, repair and service. The human body has a capacitance relative to the ground pF. If a person walks on a synthetic turf floor, this tank can be charged up to approximately U max=15 kV stored energy

When a person approaches a grounded case of an electronic device, a spark discharge will occur, and since the condition is usually met

then an aperiodic process will take place.

The strongest impact of static electricity discharges is obtained when there is a metal object in the hand (key, screwdriver, conductive bracelets, etc.). In this case, the current slope, which determines the induced interference voltages, can reach 100 A/ns.

There are also discharges of static electricity in computer rooms, control rooms, test rooms from moving objects (armchairs, instrument carts, shelves with printed paper, vacuum cleaners) to the cases of electronic devices when they are accidentally touched.

Each discharge of static electricity is accompanied by electric and magnetic fields.

In this case, in the immediate vicinity of the discharge, an electric field of 4 kV / m is created at a distance of up to 10 cm and 1 kV / m at a distance of 20 cm. Similarly, the magnetic field is 15 A / m at a distance of 10 cm and 4 A / m at a distance of 20 cm.

During the discharge of static electricity, failures in the operation of high-speed digital nodes, as well as digital interface elements, are most often observed. When applying to connectors, keyboards, display elements, etc. possible physical damage to the interface elements.

Especially dangerous is the impact of static electricity discharges on unprotected equipment components. Therefore, during any repair and adjustment work, it is necessary to comply with the requirements of electrostatic safety. When professionally assembling equipment, antistatic coatings, etc. are used. Under operating conditions, these requirements can not always be met. However, it is still worth observing the minimum precautions: for example, before touching the equipment nodes, you should touch grounded metal structures, which will allow you to remove the excess charge.

An imbalance between electric charges inside a material or on its surface is the occurrence of static electricity. The charge is retained until it is removed by the flow of an electric current or discharge. Static electricity is caused when two surfaces come into contact and separate, and at least one of the surfaces is a dielectric - a non-conductive material. Most of the people are familiar with static electricity, because they saw sparks at the moment of neutralizing the excess charge, felt the discharge on themselves and heard the crash accompanying it.

Causes of Static Electricity

Substances are composed of atoms, which in their normal state are electrically neutral, since they contain an equal number of positive charges (protons of the nucleus) and negative charges (electrons of atomic shells). Static electricity is the separation of positive and negative charges. When two materials come into contact, electrons can transfer from one material to another, resulting in an excess of positive charges on one material and an equal excess of negative charge on the other material. During the separation of materials, the resulting imbalance of charges is preserved.

In contact, materials can exchange electrons; materials that hold electrons weakly tend to lose them, while materials in which the outer shells of atoms are not completely filled tend to capture electrons. This effect is called triboelectric, and results in one material being charged positively and the other negatively. The polarity and magnitude of the charge in the separation of materials depends on the relative position of the material in the triboelectric series.

The materials are arranged in a row, one end of which is positive and the other is negative. When a pair of materials is rubbed, the material closer to the positive end of the row becomes positively charged, while the other material is negatively charged. A single triboelectric series (similar to a series of metal voltages) does not exist, just as there is no unified theory of electrization. Usually, materials with a higher dielectric constant are located closer to the positive end of the series.

The order of materials in the triboelectric series can be broken. So in a pair of silk-stele, glass is negative, in a pair of glass-zinc, zinc is negative, and in a pair of zinc-silk, not zinc, as one would expect, but silk is negatively charged. This lack of order is called a triboelectric ring.

The triboelectric effect is the main cause of static electricity in everyday life, with the mutual friction of various materials. For example, if you rub a balloon against your hair, it becomes negatively charged, and can be attracted to positively charged sources on the wall, sticking to it and violating the laws of gravity.

warning andstatic discharge

Preventing static buildup is as simple as opening a window or turning on a humidifier. An increase in the moisture content in the air will lead to an increase in its electrical conductivity, a similar effect can be achieved by air ionization.

Objects that are particularly sensitive to static discharges can be protected by applying an antistatic agent.

Particularly sensitive to discharges of static electricity are semiconductor components of electronic devices. Conductive anti-static bags are commonly used to protect these devices. People working with semiconductor circuits often ground themselves with anti-static wrist straps. To avoid the formation of static charges when in contact with the floor (for example, in hospitals), you can wear antistatic shoes with conductive soles.

Discharge

A spark is a discharge of static electricity when an excess charge is neutralized by a flow of charges from or to the environment. Electric shock is caused by irritation of the nerves when a neutralizing current flows through the human body. The stored static energy depends on the size of the object, the capacitance, the voltage to which it is charged, and the dielectric constant of the environment.

To simulate the effect of static discharge on sensitive electronic devices, the human body is represented as a 100 pF electrical capacitance charged to a voltage of 4 to 35 kV. When an object is touched, this energy is discharged in less than a microsecond. Although the total discharge energy is small, on the order of millijoules, it can damage sensitive electronic devices. Larger objects store more energy, which poses a danger to people on contact, or ignite combustible gas or dust with a spark.

Lightning

Lightning is an example of a static discharge of atmospheric electricity resulting from the contact of ice particles in thunderclouds. Usually, significant discharges can accumulate only in areas with low electrical conductivity. The discharge usually occurs at a field voltage of the order of 10 kV/cm, depending on the humidity. The discharge superheats the surrounding air, producing a bright flash and crackling sound. Lightning is just a scale version of a spark of static electricity. The flash occurs due to the heating of the air in the discharge channel to such a high temperature that it begins to emit light, like any hot body. Thunderclap - the consequences of the explosive expansion of air.

Electronic components

Many semiconductors in electronic devices are very sensitive to the presence of static and can be damaged by discharge. When handling nanodevices, it is mandatory to wear an antistatic wrist strap. Another precaution is to remove shoes with thick rubber soles and stand on a grounded metal base at all times.

Generation of static electricity in flows of flammable and combustible materials

The discharge of static electricity is a hazard in industries that use flammable substances, where small electrical sparks can cause an explosion. The movement of tiny particles of dust or liquids with low electrical conductivity in pipelines or their mechanical mixing can cause the formation of static. A static discharge in a cloud of dust or vapor can cause an explosion.

Grain elevators, paint factories, fiberglass production sites, fuel pumps can explode. Charge accumulation in a medium occurs when its electrical conductivity is less than 50 pS/m; at higher conductivity, the resulting charges recombine (recombination is a process that is the reverse of ionization), and accumulation does not occur.

Filling large transformers with transformer oil requires care, as electrostatic discharges inside the liquid can damage the transformer insulation.

Since the intensity of the formation of charges is the higher, the higher the fluid flow rate and the diameter of the pipeline, in pipelines with a diameter of more than 200 mm, the fluid flow rate is limited by the standard. Thus, the flow velocity of hydrocarbons with water content is usually limited to 1 m/s.

The formation of charges is limited to grounding. When the conductivity of the liquid is below 10 pS/m, this measure is not enough, and antistatic additives are added to the liquid.

Fuel transfer

Pumping flammable liquids such as gasoline through pipelines can generate static electricity, and discharge can ignite fuel vapors.

Similar cases occurred at gas stations and airports when refueling aircraft with kerosene. Grounding and antistatic additives are also effective here. The flow of gas in pipelines is dangerous only if there are solid particles or liquid droplets in the gas.

On spacecraft, static electricity is a great danger due to the low humidity of the environment, and this danger will have to be taken into account when carrying out planned flights to the Moon and Mars. Walking on dry surfaces can generate huge charges that can damage electronic devices.

Ozone cracking

Static discharges in the presence of air or oxygen cause the formation of ozone. Ozone damages rubber parts, in particular, leads to cracking of seals.

Static energy

The energy released during static discharges varies widely. Discharges with an energy of more than 5000 mJ are dangerous to humans. One of the standards suggests that commodities should not create a discharge with an energy higher than 350 mJ per person. The maximum voltage is limited to 35-40 kV due to the limiting factor - corona discharge. A potential below 3000V is usually not felt by a person. Walking 6 meters on PVC linoleum at an air humidity of 15% causes the formation of a potential of 12 kV, while at 80% humidity the potential does not exceed 1.5 kV.

A spark occurs at energies above 0.2 mJ. A person usually does not see or hear a spark of such energy. For an explosion to occur in hydrogen, a spark with an energy of 0.017 mJ is enough, and up to 2 mJ for hydrocarbon vapors. Electronic components are damaged at spark energies between 2 and 1000 nJ.

Applying static

Static electricity is widely used in xerographs, air filters, car paint, photocopiers, paint sprayers, printers, and aircraft fueling.

Every person on earth has encountered a natural phenomenon when, when leaving a car, he receives an electric shock. Or when petting a cat, crackling is heard and tingling of the fingertips is felt. And in the dark, glowing paths behind the hands are visible. This phenomenon is called static electricity.

It occurs when a charge accumulates on the surface of an object. This occurs when intraatomic or molecular equilibrium is disturbed.

As a result, the loss or acquisition of an electron occurs. The electronic balance is disturbed and the ions acquire a positive or negative charge.

Experiments with static electricity are known to every schoolchild when they showed an experiment with an ebonite stick and pieces of paper.

Causes

The conditions for the emergence of potential on objects is the dryness of the air. At 80% humidity, this natural phenomenon does not occur.

• When one object touches another. Potential arises after their separation. Friction, winding / unwinding of artificial materials, friction of the car body against the air, etc.;
• As a result of rapid temperature change. So, static electricity arises on objects when they are placed in a heated oven;
• Radiation and ultraviolet radiation, X-rays X-rays, strong electromagnetic and electric field;
• Guidance - there is an electric field caused by a charge. The potential arises when processing sheet or roll materials. The phenomenon occurs at the moment of separation of the material and surface. This effect can occur when moving one layer relative to another. This process is not yet fully understood. It can be compared to the separation of the plates of a capacitor. In this case, mechanical energy is converted into electrical energy.

The ability of items to accumulate charges has a negative effect on vehicles. If you do not take any measures, then damage and failure may occur.

The danger of the phenomenon

Particularly at risk of failure are electronics and all mechanisms that use electronic control units. In fire and explosion hazardous industries, sparks occur as a result of the discharge.

They may cause a fire or explosion. Protection against static electricity can completely eliminate or significantly reduce the risk of an emergency. The main danger is the occurrence of an electrical discharge.

The accumulation of charge is facilitated by dry air and reinforced concrete walls of buildings and structures. The charge polarity can be either positive or negative.

With working devices that have a rotating pulley with drive belts, the charge can reach 25,000 volts. In dry weather, electrostatic electricity of 10,000 volts can accumulate on the body of a car.

And a person who walks on a carpet in woolen socks is able to accumulate up to 6,000 volts. Even in domestic conditions, the voltage of static electricity can reach significant values.

However, it is not capable of causing significant harm to a person, due to insufficient power. The current flowing through a person is only a fraction of a milliamp.

In nature, such a phenomenon can accumulate huge values ​​and manifests itself in lightning discharges. With the release of large capacities that are capable of producing significant destruction.

Means of protection in the domestic environment

To reduce the impact on humans, a system of protection against the harmful effects of static voltage is used.

In domestic conditions, the most effective means is to increase the humidity of the air with the help of a humidifier. That not only eliminates the occurrence of stress on objects.

But it also reduces dust formation in the room. Reducing static electricity and reducing dust in the room is a log for children with allergies.

Protection methods at manufacturing enterprises

To ensure protection against static electricity in production, the following methods are used:

• Development of special methods of the technological process, excluding the accumulation of charge in the workplace;
• In industrial premises create a microclimate;
• When processing overalls and floors in the room, substances with certain physical and chemical properties are used that can relieve stress from materials.
• This is done to ensure security measures. The harm of static electricity to process equipment is reduced with the help of a "Faraday cage".

It is a casing made of fine mesh, which is connected to ground. In the same way, cables are shielded, protecting them from harmful effects.

Types of discharges

There are several types of discharge:

• Spark discharge. The occurrence of a spark between two objects. For example, a body of equipment and a person. If the discharge power is high, then there is a high probability of ignition in the presence of solvent or gasoline vapors in the air;
• Brush discharge. Occurs when charges are concentrated at sharp corners of equipment with dielectric properties. It has less energy and does not pose such a danger as a spark discharge;
• Sliding discharge. Occurs on sheet or roll materials with high resistivity. This phenomenon occurs at the moment of friction or spraying of the powder coating. It can be compared to the discharge of an ordinary capacitor. And compare with a spark discharge with the same consequences.

Additional Precautions

Considering the negative consequences, enterprises apply special measures that exclude sources of static electricity. Workers' overalls are processed to remove static electricity, which eliminates the occurrence of sparks from clothing.

In addition to creating conditions under which the accumulation of charges is reduced, powerful air ionizers are used to protect against static electricity.

Such devices have undeniable advantages. Improving the aeroionic composition of the indoor air. This helps to reduce the accumulation of charges on the clothing of service personnel, synthetic carpets and equipment.

Application in industry

The use of static electricity in industry has not found wide application. Most often, things did not go beyond laboratory installations. Therefore, all instruments were used solely to demonstrate examples of static electricity in nature.

Corona discharges have found application in industrial installations. With their help, air mixtures are purified from impurities. Paint installations have also been created that use static electricity. This makes it possible to paint complex surfaces with the least loss of paint.

Human impact

We encounter this natural phenomenon not only in enterprises. Most often, static electricity is observed in everyday life.

When removing clothes, a crackling sound is heard and sparks from the discharge are visible, and the hair on the head cannot be combed. These charges adversely affect the condition of people. The effect of such fields on human health and the immune system has not been fully elucidated.

However, it can be said that being in an apartment where there is static electricity has a negative effect on a person. The main violations can be noted:

• There are disorders in the central nervous system, which are accompanied by vasospasm and high blood pressure;
• Persistent headaches;
• Irritability and emotional excitability;
• Sleep disturbances appear, and appetite disappears;
• A phobia appears - the fear of receiving a discharge, which is accompanied by painful sensations.

Therefore, it is very important to know the methods of protection against static electricity in everyday life. For this, techniques such as grounding of all electrical appliances are used.

Use of household air humidifiers. Regularly carry out wet cleaning of the apartment, preferably in the morning and evening.

In order to ensure the removal of static electricity from synthetic fabrics, they are treated with antistatic liquids. Everyone should be aware of the dangers of being in the field for a long time and use ESD protective equipment.