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How an LED works and works. How is an LED lamp made? LED working principle main characteristics

LEDs for humanity have become one of the most common light sources for industrial and domestic needs. This semiconductor device has one electrical junction, it converts electricity into visible light energy. The phenomenon was discovered by Henry Joseph Round in 1907. The first experiments were carried out by the Soviet experimental physicist O.V. Losev, who in 1929 managed to obtain a working prototype of a modern LED.

The first modern LEDs ( LED, LED, LED) were created in the early sixties. They had a faint red glow and were used as turn-on indicators in a variety of instruments. In the 90s, blue, yellow, green and white LEDs appeared. Many companies began to produce them on an industrial scale. Today, LED diodes are used everywhere: in traffic lights, light bulbs, cars and so on.

Device

The LED is a semiconductor device with an electron-hole junction, which creates optical radiation when a current passes through it in the forward direction.

The standard indicator LED is made up of the following parts:

1 - Epoxy lens
2 - Wire contact
3 - Reflector
4 - Semiconductor (Determines the color of the glow)
5 and 6 - Electrodes
7 - Flat cut

The cathode and anode are fixed at the base of the LED. The entire device is hermetically sealed from above with a lens. A crystal is placed on the cathode. The contacts have conductors that are connected to the crystal by a p-n junction (connection wire for combining two conductors with different types of conductivity). To create a stable operation of the LED, a heat sink is used, which is necessary for lighting fixtures. In indicator instruments, heat is not decisive.

DIP diodes have leads that are mounted in the holes of the printed circuit board, they are connected by soldering to an electrical contact. There are models with several crystals of different colors in one case.

SMD LEDs are the most popular light sources of any format today.

  • The base of the case, where the crystal is attached, is an excellent conductor of heat. Thanks to this, heat removal from the crystal has improved significantly.
  • In the structure of white LEDs, there is a phosphor layer between the lens and the semiconductor, which neutralizes ultraviolet radiation and sets the required color temperature.
  • SMD components with a wide beam angle do not have a lens. In this case, the LED itself is distinguished by the shape of a parallelepiped.
Chip-On-Board (COB) represent the latest practical advance that should take the lead in white LEDs in artificial lighting.


The device of LEDs using COB technology assumes the following:
  • Dozens of crystals without a substrate and a case are attached to the aluminum base by means of dielectric glue.
  • The resulting matrix is ​​covered with a common layer of phosphor. The result is a light source that has a uniform light distribution without the possibility of shadows.

A variation of Chip-On-Board is Chip-On-Glass (COG) technology, which involves placing many small crystals on a glass surface. For example, these are filament lamps, where the radiating element is a glass rod with LEDs that are coated with a phosphor.

Operating principle
Despite the technological features and varieties, the operation of all LEDs is based on the general principle of the functioning of the radiating element:
  • The conversion of electricity into a luminous flux is carried out in a crystal, which is made of semiconductors with a variety of types of conductivity.
  • An n-conducting material is provided by doping it with electrons, and a p-conducting material with holes. As a result, additional charge carriers of different directions appear in adjacent layers.
  • When a forward voltage is applied, the movement of electrons, as well as holes, to the p-n junction starts.
  • Charged particles pass through the barrier and begin to recombine, as a result of which an electric current flows.
  • The process of recombination of an electron and a hole in the p-n-junction zone is accompanied by the release of energy in the form of a photon.

In general, this physical phenomenon is characteristic of all semiconductor diodes. However, the wavelength of a photon in most cases is located outside the visible radiation spectrum. In order for an elementary particle to move in the range of 400-700 nm, scientists conducted many experiments and experiments with different chemical elements. As a result, new compounds appeared: gallium phosphide, gallium arsenide and more complex forms. Each of them has its own wavelength, that is, its own color of radiation.
In addition, in addition to the useful light emitted by the LED, a certain amount of heat is generated at the p-n junction, which reduces the efficiency of the semiconductor device. That is why the design of high-power LEDs provides for efficient heat dissipation.

Varieties

At the moment, LED diodes can be of the following types:
  • Lighting, that is, with great power. Their level of illumination is equal to tungsten and fluorescent light sources.
  • Indicator - with low power, they are used for lighting in devices.

Indicator LED-diodes according to the type of connection are divided into:
  • Double GaP (gallium, phosphorus) - have green and orange light in the structure of the visible spectrum.
  • Triple AIGaAs (aluminum, arsenic, gallium) - have yellow and orange light in the structure of the visible spectrum.
  • Triple GaAsP (arsenic, gallium, phosphorus) - have red and yellow-green light in the structure of the visible spectrum.
According to the type of housing, LED elements can be:
  • DIP- an outdated model of low power, they are used to illuminate light displays and toys.
  • "piranha" or Superflux- analogues of DIP, but with four contacts. They are used for lighting in cars, they heat up less and are better attached.
  • smd- the most common type, used in a variety of light sources.
  • COB These are advanced SMD LEDs.
Application
The scope of LEDs can be roughly divided into two broad categories:
  1. Lighting.
  2. Using direct light.

An LED in lighting is used to illuminate an object, space, or surface, rather than being directly visible. These are interior lighting, flashlights, lighting of building facades, lighting in cars, backlighting of mobile phone keys and displays, and so on. LED diodes are widely used in communicators and cell phones.

Direct LED light is used to transmit information, for example, in full-color video displays, in which LED diodes form the pixels of the display, as well as in alphanumeric displays. Direct light is also used in signaling devices. For example, these are turn indicators and brake lights of cars, traffic lights and signs.

Future of LEDs

Scientists are creating a new generation of LEDs, for example, based on nano-crystalline thin films of perovskite. They are cheap, efficient and durable. The researchers hope that such LED diodes will be used instead of conventional laptop and smartphone screens, including in household and street lighting.

Fiber LED diodes are also being created, which are designed to create wearable displays. Scientists believe that the method being created for the production of fiber LEDs will allow mass production and make the integration of wearable electronics into clothing and textiles completely inexpensive.

Typical characteristics

LEDs are characterized by the following parameters:

  • color characteristic.
  • Wavelength.
  • Current strength.
  • Voltage (type of applied voltage).
  • Brightness (light intensity).

LED brightness is proportional to the current flowing through it, that is, the higher the voltage, the greater the brightness. The unit of luminous intensity is the lumen per steradian and is also measured in millicandels. There are bright (20-50 mcd.), As well as super bright (20,000 mcd. and more) white LED diodes.

The magnitude of the voltage drop is a characteristic of the allowable values ​​of direct and reverse switching. If the voltage supply is higher than these values, then an electrical breakdown is observed.

The strength of the current determines the brightness of the glow. The current strength of lighting elements is usually 20 mA, for indicator LEDs it is 20-40 mA.

The color of the LED emission depends on the active substances introduced into the semiconductor material.

The wavelength of light is determined by the energy difference during the transition of electrons at the stage of recombination. It is determined by dopant impurities and the original semiconductor material.

Advantages and disadvantages
Among the advantages of LEDs are:
  • Low power consumption.
  • Long service life, measured 30-100 thousand hours.
  • High light output. LEDs give 10-250250 lumens of light output per watt of power.
  • No poisonous mercury fumes.
  • Wide application.
Flaws:
  • Poor performance for low-quality LEDs created by unknown manufacturers.
  • Relatively high price of high-quality LEDs.
  • The need for quality power supplies.

The first light-emitting diodes (LED, LED, LED) were developed in the early sixties to replace miniature incandescent lamps. These were with a very weak glow and were used as turn-on indicators in various devices.

In the early nineties, the blue LED was created, followed by green, yellow and white. Today, the LED is one of the most widely used lighting elements. This is a light device in a plastic molded case (different colors) with two leads with a soldered crystal.

The case performs two functions - it is a lens and a protective coating. The LED is powered by current, for which a voltage converter is built into the base. The brightness of the glow is proportional to the voltage.

Element device

The LED consists of the following parts:

  • base;
  • lens;
  • cathode (-);
  • anode (+);
  • crystal (semiconductor chip);
  • reflector (diffuser).

The cathode and anode are fixed at the base, the entire device is hermetically sealed from above by a lens (flask). A crystal is attached to the cathode. Conductors are installed on the contacts, connected to the crystal by a p-n junction (connecting wire connecting two conductors with different types of conductivity).

A heat sink is necessary to maintain stable operation of the LED. In indicator LEDs, heat does not accumulate due to low power. For lighting - the base is directly soldered to the surface to ensure heat dissipation.

LED from inside

The principle of operation of diodes for dummies

To understand how an LED works, you need to know what a p-n junction is. This is the region in which p and n type semiconductors come into contact, as a result of which one type of conductivity passes to another. N type contains conduction electrons as charge carriers. A p-type semiconductor is a positive charge carrier (holes).

The anode (p type) is the positive electrode, the cathode (n type) is the negative electrode. The outer surface of the cathode and anode contains contact metal pads with soldered leads. When a positive charge of electricity is supplied to the anode, and a negative charge to the cathode, then a current begins to flow at the p-n junction between the crystal and the cathode.

If the inclusion is direct, then electrons from the n and region and holes from the p region will rush towards each other. In the process of doping (exchange of electrons) at the boundary of the hole-electron transition, their exchange will occur. If a negative voltage is applied from the n-type material side, a forward bias occurs. During recombination (exchange), energy is released in the form of photons.

In order to convert the photon flux into visible light, the material is selected so that the photon wavelength is within the visible region of the color spectrum with a wavelength of 700 to 400 nm.

The principle of operation of the LED

Kinds

The types of LEDs currently available are::

  • indicator - with low power, for backlighting in devices;
  • lighting - with high power, the level of illumination corresponds to conventional (fluorescent and tungsten) light sources.

According to the type of connection, the indicator ones are divided into:

  • ternary AIGaAs (aluminum - gallium - arsenic)– orange and yellow light in the regions of the visible color spectrum;
  • triple GaAsP (gallium - arsenic - phosphorus)- yellow-green and red light in the visible spectrum;
  • double GaP (gallium - phosphorus)– orange and green light in the visible spectrum.

LED elements differ in case type:

  • DIP- equipped with a built-in optical system of a lens, a crystal and a pair of contacts. An outdated model of the lowest power, used to illuminate toys, light displays;
  • Superflux or "piranha"- similar to DIP, equipped with four contacts, better fastened and less heated due to. Used for lighting in cars;
  • smd- the most common type for many light sources. They are a chip (crystal) mounted directly on the surface of the board;
  • COB– advanced SMD LEDs. Equipped with several crystals (chips) installed on one board. Mounted on ceramic and aluminum bases.

Photo lamp with new types of SMD LEDs

More advanced SOV models still cannot always replace SMD LEDs.

Main technical characteristics

Voltage

The voltage needed to drive an LED is not the supply voltage, but the amount of voltage drop across the LED. Fluctuating supply voltage causes the LED to burn out. The voltage is directly related to the color.

For normal operation, when connecting an LED, it is necessary to correctly track the current, not the voltage.

Current strength

The LED works on constant or pulsating current. By raising or lowering the intensity, you can vary the brightness of the glow. The operating current of the indicator LEDs is 20 - 40 mA. The current strength of the lighting elements is from 20 mA. COBs (for 4 chips), for example, are rated at 80 mA. Single watt LEDs draw approximately 300-400 mA.

Wavelength and color characteristic

The color emitted by the diode depends on the wavelength of the light emitted. It is measured in nanometers (0.000000001 meters). Monochromatic (single frequency) radiation is related to the wavelength traveling inside. Wavelength limits are related to primary colors in a certain way.

The color of the LED emission changes when active substances are introduced into the semiconductor material. To obtain red LEDs, aluminum indium - gallium (AllnGaP) is used as a semiconductor, for colors of the blue - blue and green spectrum - indium - gallium nitride (InGaN). To obtain, for example, white light, a blue LED crystal is coated with a thin layer of phosphor, which emits yellow and red light under the action of the blue spectrum.

Mixing colors results in white light. White LEDs are defined by their color temperature, measured in K.

Lamps with diodes can be of different colors

LED board

The board is designed to mount LEDs in any required number and position. The payment form is:

  • rectangular;
  • ruler;
  • round;
  • square;
  • stellate
  • arbitrary.

The LED board is made of a dielectric material. Its main function is heat dissipation.

Board types:

  • metal (one-sided, two-sided and multilayer);
  • insulated metal substrates (single-sided, double-sided and multilayer, rigid-flexible).

Boards made of aluminum do not need fans for forced cooling. All structural elements acquire a longer service life due to the absence of overheating.

For more information about the history of occurrence and principles of operation of LED elements, see the video:

LEDs are one of the newest sources of lighting, have a wide range of applications and great prospects. Due to the ratio of all parameters, the LED type of lighting can become the leading one among a variety of lighting fixtures and various light sources.

The device and principle of operation of LED lamps. The main parts of the lighting device:

LEDs;
- driver;
- plinth;
- frame.

The principle of its operation completely repeats the processes occurring in an ordinary semiconductor diode with a p-n junction made of silicon or germanium: when a positive potential is applied to the anode, and a negative one to the cathode, the movement of negatively charged electrons to the anode begins in the materials, and holes to the cathode. As a result, the diode passes electric current in only one direct direction.

However, the LED is made of other semiconductor materials, which, when bombarded in the forward direction by charge carriers (electrons and holes), carry out their recombination with transfer to another energy level. As a result, photons are released - elementary particles of electromagnetic radiation in the light range.

Even in electrical circuits, the designations of ordinary diodes are used as their designations, only with the addition of two arrows indicating the emission of light.

Semiconductor materials have different photon emission properties. Substances such as gallium arsenide (GaAs) and gallium nitride (GaN), being direct-gap semiconductors, are simultaneously transparent to the visible spectrum of light waves. When they replace p-n junction layers, light is released.

The layout of the layers used in the LED is shown in the figure below. Their small thickness of the order of 10÷15 nm (nanomicrons) is created by special methods of chemical vapor deposition. The layers contain contact pads for the anode and cathode.

As with any physical process, during the conversion of electrons into photons, there are energy losses due to the following reasons:

Some of the light particles are simply lost inside even such a thin layer;
- when leaving the semiconductor, optical refraction of light waves occurs at the crystal/air interfaces, distorting the wavelength.

The use of special measures, such as the use of a sapphire substrate, makes it possible to create a greater luminous flux. Such designs are used for installation in lighting lamps, but not for conventional LEDs used as indicators, shown in the figure below.

They have a lens made of epoxy resin and a reflector to guide the light. Depending on the purpose, the light can propagate in a wide angle range of 5-160°.

Expensive LEDs produced for lighting lamps are manufactured by manufacturers with a Lambert diagram. This means that their brightness is constant in space and does not depend on the direction of radiation and the angle of observation.

The dimensions of the crystal are very small and a small amount of light can be obtained from one source. Therefore, for lighting lamps, such LEDs are combined in fairly large groups. At the same time, it is very problematic to create uniform illumination from them in all directions: each LED is a point source.

The frequency spectrum of light waves from semiconductor materials is much narrower than from ordinary incandescent lamps or the sun, which tires the eyes of a person, creates a certain discomfort. In order to correct this shortcoming, a phosphor layer is introduced into individual LED designs for illumination.

The magnitude of the emitted light flux of semiconductor materials depends on the current passing through the p-n junction. The greater the current, the higher the radiation, but up to a certain value.

Small dimensions, as a rule, do not allow the use of currents exceeding 20 milliamps for indicator structures. Powerful lighting lamps use heat dissipation and additional protection measures, the use of which, however, is strictly limited.

At start-up, the luminous flux of the lamp increases proportionally with increasing current, but then, due to the formation of heat losses, it begins to decrease. It should be understood that the process of emitting photons from the conductor is not associated with thermal energy, LEDs are cold light sources.

However, the current passing through the LED at the points of contact between the various layers and electrodes overcomes the contact resistance of these sections, which causes heating of the materials. The generated heat initially only creates energy losses, but as the current increases, it can damage the structure.

The number of LED crystals installed in one lamp can exceed a hundred working elements. For each of them it is necessary to bring the optimal current. For this, fiberglass boards with conductive paths are created. They can have a variety of designs.

LED crystals are soldered to the contact pads of the boards. Most often they are formed into certain groups and fed in series with each other. The same current is passed through each created chain.

Such a scheme is technically easier to implement, but it has one main drawback - if any one contact is broken, the entire group stops shining, which is the main cause of lamp failure.


Drivers. The supply of constant voltage to each group of LEDs is carried out from a special device, which was previously called a power supply, and now the term “driver”.

This device has the functions of converting the input voltage of the network, for example, ~ 220 Volts of the apartment or 12 Volts of the car network into the optimal power supply for each series group.

The supply of one stabilized current to each crystal in a parallel circuit is technically difficult and is used in rare cases. The driver can work on the basis of a transformer or other circuit. Among them are the following options. Depending on the configuration and the number of applied elements, they may be different:

The simplest and cheapest drivers are powered by a stabilized voltage, the network of which is protected from surges and surges. They may even lack a current-limiting resistor in the output power circuit, which is typical for rechargeable flashlights, the LEDs of which are often connected directly to the battery output.

As a result, it turns out that they are powered by an overestimated current, and although they shine quite brightly, they burn out very often. When using cheap lamps with drivers without surge protection of the lighting network, the LEDs also often burn out without having worked out the declared resource.

Well-designed power supplies generate little to no heat during operation, and cheap or overloaded drivers use some of their electricity to heat up. Moreover, such useless losses of electric power can be comparable, and in some cases exceed the energy spent on the release of photons.

The current generation seeks to minimize their costs. The advantage of the LED lamp is low power consumption. With a power consumption of 10 W, the LED lamp gives the same illumination as a 100 W incandescent lamp. This indicator is also 2 times higher than in fluorescent lamps.

Another plus is a much longer working life compared to an incandescent lamp. The combination of low power consumption with high durability compensates for the high cost.

This article discusses the device of an LED lamp, which consists of the following elements:

  • diffuser;
  • Light-emitting diode;
  • radiator;
  • driver;
  • plinth.

Device and principle of operation

The design of the LED lamp is quite complex. Consider its structure and purpose of the main elements.

The light source in the LED lamp is a light-isolating diode, consisting of a semiconductor crystal with two leads (cathode and anode) and an optical system. Further in the text, the abbreviation SD or LED will be used.

Consider the principle of operation of the LED lamp. When an electric current passes through a semiconductor in the forward direction, charge carriers (electrons and holes) recombine. As a result of this, optical emission of photons occurs (due to the transition of electrons to another energy level).

Also in the lamp is a driver (special microcircuit), which provides power to the LED. The radiator (cooling system) collects and removes excess heat. Diffuser minimizes light loss.

In the diagrams, LEDs are conventionally designated as diodes with arrows, which indicate optical radiation (Fig. 2).

The simplest LED lamp circuit

A feature of the circuit shown in Fig. 3 is 2 LEDs working back-to-back. In this arrangement, each LED performs a protective function. Prevents the reverse voltage from damaging the network of another LED, and also increases the pulsation frequency of the LED lamp to a value of 100 Hz. This frequency indicator will favorably affect your vision.

One of the LEDs can be replaced with a rectifier diode that performs a protective function. It is included in the circuit in the direction of the replaced LED. In this arrangement of elements, the pulsation frequency of the LED is 25 Hz.
Resistor R1 must have a power of at least 5 W and a resistance of 10-11 kOhm. Then the current flowing in the LED will be 20 mA. The resistance R1 is selected according to the nominal forward current of the LED.
This lamp can be made in the body of a damaged compact LL.

The simplest LED lamp circuit

The structure of LED devices of various manufacturers

The device of LED lamps with a voltage of 220 V of various manufacturers has slight differences. The entire selection of LED lamps is conditionally divided into several groups: branded, low quality and filament.

branded products

The design of LED lamps from leading brands producing LED products necessarily includes:

  • diffuser;
  • chips;
  • printed circuit board made of aluminum on a heat-conducting paste (guarantor of the optimal temperature of the operating mode of the chips);
  • a driver built according to the scheme of a galvanically isolated pulse-width modulator of a current stabilizer;
  • plinth base made of polyethylene terephthalate. Works as a reliable protection against electric shock;
  • nickel-plated brass base. Anti-corrosion material that creates a reliable contact with the cartridge.

 Sectional LED lamp

The main visible difference of the lamp from this group is a volumetric radiator, painted with white polymer. Its surface can be either smooth or ribbed. If we compare such an LED lamp with cheaper representatives, then it has a large mass.

The diffuser material can be glass or plastic. Its shape remains unchanged - a hemisphere. The fasteners of the diffuser to the radiator can be latches or shrinkage on the sealant. Below it is a board with SMD LEDs, securely fixed to the heatsink. Below is the driver board. The driver circuit includes:

  • pulse transformer,
  • microchips,
  • polar capacitors,
  • a huge number of planar elements.

It has a large cuff density. The driver is located under the lamp body and is the connector of the base and radiator. The driver block is connected to the board by soldering or a contactor.

Low quality products

A hallmark of poor quality lamps is the possible absence of elements such as a heatsink and a driver. The driver function is performed by a simple power supply. It cannot convert AC to DC. The power supply is located in the central part of the board next to the LEDs. The perforation of the body acts as a heatsink in the lamp. Due to the inefficient cooling function, overheating and failure of the SD are inevitable.

The board is fastened to the case by means of a latch. The electrical connection of the board with the base is carried out by soldering. This design is simple, but cannot ensure the reliability and long life of LED light bulbs.

Filament lamps (FL)

The development of LED lamps does not stand still. The next novelty in the market of lighting products was a filament lamp.


Literally from English "filament" means a thread. Visually, this lamp is similar to an incandescent lamp. A distinctive feature of PL is that it does not require additional heat removal. Its use in everyday life has both practical and aesthetic applications.

Let's take a closer look at the structure of a filament lamp. The number of LED filaments (the main elements of the FL) is directly proportional to the lamp power. A thin glass rod on which SMD LEDs are located, which are electrically connected to each other - this is the filament. The yellow color of the PL is due to the phosphor deposited along the entire length. Heat removal in this product is carried out through a flask filled with a gas mixture.

Often, manufacturers are forced to place a low-quality power module in the PL base. This is due to flaws in the design of the filament lamp, which leads to an increase in the ripple factor, which adversely affects vision. To eliminate this shortcoming, work is underway to modernize the design of the FL. To accommodate a high quality driver, a plastic insert is made in the form of a ring. It is located between the flask and the base.

Content:

The issues of reducing electricity consumption are solved not only at the state level. This problem is relevant for ordinary consumers. In this regard, in apartments, offices and other institutions, not only powerful, but also economical light sources are being widely introduced. Among them, LED lamps are becoming more and more widespread. The device and principle of operation of the LED lamp allows you to use it with a standard cartridge and connect it to a 220 V electrical network. In order to make the right choice, you need to know the main advantages and features of modern light sources.

The principle of operation of LED lamps

The operation of LED lamps uses physical processes that are much more complicated than those used in conventional incandescent metal filament lamps. The essence of the phenomenon is the appearance of a luminous flux at the point of contact of two substances from dissimilar materials, after an electric current is passed through them.

The main paradox is that each of the materials used is not a conductor of electric current. They belong to the category of semiconductors and are capable of passing current only in one direction, provided they are interconnected. In one of them, negative charges must necessarily prevail - electrons, and in the other - ions with a positive charge.

In addition to the movement of electric current, other processes occur in semiconductors. During the transition from one state to another, thermal energy is released. Through experiments, it was possible to find such combinations of substances in which, along with the release of energy, light radiation appeared. In electronics, all devices that pass current in only one direction began to be called, and those that have the ability to emit light began to be called LEDs.

At the very beginning, the emission of photons by semiconductor compounds covered only a narrow part of the spectrum. They could only emit red, yellow or green light, with a very low luminosity. Therefore, for a long time, LEDs were used only as indicator lamps. To date, such materials have been obtained, the compounds of which have made it possible to significantly expand the range of light radiation and cover almost the entire spectrum. Nevertheless, the length of some waves always prevails in the glow. Therefore, LED lamps are divided into sources of cold light - blue and warm glow - mostly red or yellow.

Device of LED light sources

The appearance of LED lamps practically does not differ from traditional light sources with a metal filament. They are equipped with a thread, which allows them to be used with conventional cartridges and not to make changes to the electrical equipment of the premises. However, LED lamps differ significantly in their complex internal structure.

They include a contact base, a case that acts as a radiator, a power and control board, a board with LEDs and a transparent cap. When planning the use of LED lamps in a 220 V network, it should be remembered that they will not be able to work with such a current and voltage. In order to prevent burnout of luminaires, power and control boards are installed in their cases, reducing voltage and rectifying current.

The design of such a board has a serious impact on the life of the lamp. In some models, only a resistor is installed in front, and in some cases, unscrupulous manufacturers do without it. As a result, the lamps give a very bright glow, but burn out very quickly due to the lack of stabilizing devices. Therefore, high-quality lamps are certainly equipped with stabilizers, for example, ballast transformers. The most common control circuits use smoothing filters, which include a capacitor and a resistor. In the most expensive models, microcircuits are used in control and power units.

Each individual LED emits a rather weak light. Therefore, to achieve the desired lighting effect, the required number of elements is grouped. For this purpose, a board made of a dielectric material with applied conductive tracks is used. Approximately the same boards are used in other electronic devices.

The LED board is also a step-down transformer. To this end, all elements are connected in series in a common circuit, and the mains voltage is evenly distributed between them. The only significant drawback of such a circuit is the breakage of the entire chain in the event of a burnout of at least one LED.

A transparent cap protects the entire lamp from moisture, dust and other negative influences. Some properties of the cap allow you to enhance the overall glow. The fact is that its inner side is covered with a layer of phosphor, which begins to glow under the action of the energy of quanta. Therefore, the outer surface of the cap looks matte. The phosphor has a wider emission spectrum, several times higher than that of LEDs. As a result, the radiation becomes comparable to natural sunlight. Without such a coating, LEDs are irritating to the eyes, causing fatigue and pain.

It is best to study the useful qualities, device and principle of operation of LED lamps on diagrams at a voltage of 220 volts. Most often, such lamps are used in industrial and street lighting, and in domestic conditions, traditional light sources are replaced by LED bulbs operating at low voltage, mainly from 12 volts. However, the power of the lamp and its light output are not directly related to each other. This factor should be taken into account when choosing LED lamps.

In LED lamps designed for 220 volts, there is no transformer in the circuit. In this regard, there is additional savings in the operation of such lamps. This feature distinguishes them from LED lamps with other powers. Therefore, the choice of fixtures is not based on power, but on the degree of illumination created by them.

Advantages of LED lamps

Currently, great importance is attached to the economical and durable operation of lighting devices. Therefore, luminaires that create bright lighting with the release of a minimum amount of heat and low power consumption come to the fore. They have low sensitivity to current and voltage drops, can withstand a large number of on and off.

All these qualities are fully possessed by LED lamps. They have several varieties that differ in design and technical characteristics, which allows you to choose the most suitable option. All lamps are distinguished by the presence or absence, the degree of environmental safety, the need to use rectifiers and other additional devices.