• Diode lamp device. Determining the extent of damage. According to the types of LEDs used on

    The task of reducing the amount of energy consumed is no longer just technical problem and moved into the area of ​​strategic direction of state policy. For the average consumer, this titanic struggle results in the fact that he is simply forcibly forced to switch from the familiar and simple-as-an-egg incandescent lamp to other light sources. For example, to LED lamps. For most people, the question of how an LED lamp works comes down only to the possibility of it practical application– Is it possible to screw it into a standard socket and connect it to a 220 volt household network. A short excursion into the principles of its operation and structure will help you make an informed choice.

    The operating principle of an LED lamp is based on much more complex physical processes than one that emits light through a red-hot metal thread. He is so interesting that it makes sense to get to know him better. It is based on the phenomenon of light emission that occurs at the point of contact of two dissimilar substances when an electric current passes through them.

    The most paradoxical thing about this is that the materials used to provoke the effect of light emission do not conduct electric current at all. One of them, for example, silicon is a ubiquitous substance and is constantly trampled under our feet. These materials will pass current, and only in one direction (that’s why they are called semiconductors), only if they are connected together. To do this, positively charged ions (holes) must predominate in one of them, and negative ones (electrons) must predominate in the other. Their presence or absence depends on the internal (atomic) structure of the substance and a non-specialist should not bother with the question of unraveling their nature.
    The emergence of an electric current in a connection of substances with a predominance of holes or electrons is only half the battle. The process of transition from one to another is accompanied by the release of energy in the form of heat. But in the middle of the last century, mechanical compounds of substances were found in which the release of energy was also accompanied by a glow. In electronics, a device that allows current to flow in one direction is called a diode. Semiconductor devices made from materials that can emit light are called LEDs.

    Initially, the effect of emitting photons from a semiconductor compound was possible only in a narrow part of the spectrum. They glowed red, green or yellow. The strength of this glow was extremely small. The LED was used only as an indicator lamp for a very long time. But now materials have been found whose combination emits light of much greater intensity and in a wide range, almost the entire visible spectrum. Almost, because a certain wavelength predominates in their glow. Therefore, there are lamps with a predominance of blue (cold) and yellow or red (warm) light.

    Now that you understand in general terms the principle of operation of an LED lamp, you can move on to answering the question about the design of 220 V LED lamps.

    Design of LED lamps

    Externally, light sources that use the effect of photon emission when electric current passes through a semiconductor are almost no different from incandescent lamps. The main thing is that they have the usual metal base with a thread, which exactly replicates all standard sizes of incandescent lamps. This allows you to not change anything in the electrical equipment of the room to connect them.
    However, the internal structure of a 220 volt LED lamp is very complex. It consists of the following elements:

    1) contact base;

    2) a housing that simultaneously plays the role of a radiator;

    3) power and control boards;

    4) boards with LEDs;

    5) transparent cap.

    Power and control board

    Understanding how they work led lamps 220 volts, first of all it is worth understanding that semiconductor elements cannot be powered from AC and voltages of this magnitude. Otherwise they will simply burn out. Therefore, in the body of this light source there is necessarily a board that reduces the voltage and rectifies the current.

    The durability of the lamp largely depends on the design of this board. More precisely, what elements are at its input. The cheap ones have nothing except a resistor in front of the rectifying diode bridge. Miracles often happen (usually in lamps from the Middle Kingdom) when even this resistor is not present and the diode bridge is directly connected to the base. Such lamps shine very brightly, but their service life is extremely low if they are not connected through stabilizing devices. For this you can use, for example, ballast transformers.

    The most common schemes are those in which a smoothing filter consisting of a resistor and a capacitor is created in the power supply circuit of the lamp control circuit. In the most expensive LED lamps, the power and control unit is built on microcircuits. They smooth out stress surges well, but their working life is not too high. Mainly due to the inability to establish effective cooling.

    LED board

    No matter how hard scientists try, inventing new substances with high radiation efficiency in the visible part of the spectrum, the principle of operation of an LED lamp remains the same, and each of its individual luminous elements is very weak. To achieve the desired effect, they are grouped in groups of several dozen and sometimes hundreds of pieces. For this, a dielectric board is used, on which metal conductive tracks are applied. It is very similar to those used in televisions, motherboards computers and other radio devices.
    The LED board performs another important function. As you have already noticed, there is no step-down transformer in the control unit. Of course, it is possible to install it, but this will lead to an increase in the dimensions of the lamp and its cost. The problem of lowering the supply voltage to a nominal value that is safe for the LED is solved simply but extensively. All luminous elements are included in series, like in a Christmas tree garland. For example, if 10 LEDs are connected in series to a 220 volt circuit, then each will get 22 V (however, the current value will remain the same).
    The disadvantage of this circuit is that a burnt-out element breaks the entire circuit and the lamp stops shining. In a non-working lamp, out of a dozen LEDs, only one or two may be faulty. There are craftsmen who resolder them and move on with their lives, but most inexperienced users throw the entire device in the trash.

    By the way, recycling LED lamps is a separate headache, since they cannot be mixed with ordinary household waste.

    Transparent cap

    Basically, this element plays the role of protection against dust, moisture and playful hands. However, it also has a utilitarian function. Most LED lamp covers have a matte appearance. This solution might seem strange, since the power of the LED radiation is weakened. But its usefulness for specialists is obvious.

    The cap is matte because a layer of phosphor is applied to its inner side - a substance that begins to glow under the influence of energy quanta. It would seem that here, as they say, oil is oil. But the phosphor has an emission spectrum several times wider than that of an LED. It is close to natural solar. If you leave the LEDs without such a “gasket”, then their glow will make your eyes get tired and hurt.

    What are the benefits of such lamps

    Now that you already know a lot about how an LED lamp works, it’s worth dwelling on its advantages. The main and indisputable thing is low energy consumption. A dozen LEDs produce radiation of the same intensity as a traditional incandescent lamp, but semiconductor devices consume several times less electricity. There is another advantage, but it is not so obvious. Lamps with this operating principle are more durable. True, provided that the supply voltage is as stable as possible.

    It is impossible not to mention the disadvantages of such lamps. First of all, this concerns the spectrum of their radiation. It is significantly different from the sun - what the human eye has been accustomed to perceiving for thousands of years. Therefore, for your home, choose those lamps that shine yellow or reddish (warm) and have matte caps.

    The advent of LED or LED lamps contributed to the beginning of a new stage in the lighting industry. More recently, such lighting fixtures were extremely rare, but now a huge assortment of different LED lamps is displayed by everyone. large stores. The LED, unlike a conventional incandescent lamp, has its own startup circuit.

    It is installed in the light bulb itself, between the imitation bulb and the socket. Therefore, this place is made opaque. Getting to the board with diodes is not that difficult, but some effort will be required for disassembly. Although experience shows that most manufacturers use similar models of starting devices for this, small differences still remain.

    Friends, I welcome everyone to the “Electrician in the House” website. Today I want to give you an overview of the insides of the LED lamps that I ordered from Aliexpress. The lamp consists of 72 diodes. It uses SMD LEDs, also known as Surface Mounting Device. Let's start disassembling, I think you will also be very interested.

    Operating principle of LED lamp

    Produced led light bulbs at 220V may differ in external design, but the principle internal structure persists for all models. Light emission in lamps is carried out by LEDs, the number and size of crystals of which can vary depending on the power and cooling capabilities. Their color spectrum is determined by the substance included in the structure of each crystal.

    To get to the starting driver, you need to carefully remove the protective “skirt” of the lamp. A printed circuit board or assembly of interconnected radio elements will open under it. At the driver input there is a diode bridge connected to the electric base of the lamp in contact with the socket. Thanks to it, the alternating supply voltage is rectified into constant voltage, supplied to the board and through it supplied to the LEDs.

    To better dissipate the emitted flux and protect the crystals from touching, as well as to avoid their contact with foreign objects, a scattering protective glass (transparent plastic bulb) is installed outside. Therefore, in their appearance they are very reminiscent of traditional light sources.

    To screw the light bulb into the socket, their bases are made standard sizes E14, E27, E40, etc. This allows you to use LED lamps in home network without resorting to any changes in the electrical wiring.

    Design and purpose of lamp parts

    Each LED lamp consists of the following parts:

    #1 . Diffuser - a special hemisphere that increases the angle and uniformly scatters the directed beam of LED radiation. In most cases, the element is made from transparent and translucent plastics or frosted polycarbonate. Due to this, the products do not break when dropped. The element is absent only in analogues of fluorescent lamps; there it is replaced by a special reflector. In devices with LEDs, the heating of the hemisphere is insignificant and several times less than in conventional filamentous electric lamps.

    #2 . LED chips– the main components of new generation lamps. They are installed either one at a time or in dozens. Their number depends on the design features of the product, its size, power and the presence of devices for heat removal. U good producers It is not practiced to skimp on quality LED matrices, since they determine all the operating parameters of the emitter and the duration of its operation. However, in the world such companies can be counted on one hand. The diodes in the matrices are interconnected, and if one fails, the entire lamp fails.

    #3 . Printed circuit board. In their manufacture, anodized aluminum alloys are used, which can effectively remove heat to the radiator, which will create optimal temperature for uninterrupted operation of the chips.

    #4 . Radiator, which removes heat from a printed circuit board with LEDs recessed in it. For casting radiators, aluminum and its alloys are also chosen, as well as special forms With a large number separate plates that help increase the heat dissipation area.

    #5 . Capacitor, cleaning voltage ripple, supplied to the LED crystals from the driver board.

    #6 . Driver that smoothes, reduces and stabilizes the input voltage electrical network. No one can do without this miniature printed circuit board. LED matrix. There are external and built-in drivers. Majority modern lamps equipped with built-in devices that are mounted directly in their housing.

    #7 . Polymer base, resting closely against the base part, protecting the housing from electrical breakdowns, and those changing light bulbs from accidental electric shock.

    #8 . Base, providing connection to the cartridges. Typically, nickel-plated brass is used in its manufacture. This guarantees good contact and long-term corrosion protection.

    Also, a significant difference between LED devices and their conventional prototypes was the location of the maximum heating zone. For other types of emitters, heat spreads from the outside of the surface. LED crystals heat their printed circuit board With inside. Therefore, they require timely removal of heat from inside the lamp, and this is structurally solved by installing cooling radiators.

    Design of a corn lamp

    For some reason, everyone calls the lamp that we are going to disassemble today “corn”. Although looking at appearance There really are similarities. I ordered a whole set of these lighting lamps for a soft box. For those who haven't seen it yet, there is a video on the YouTube channel.

    External provides open access to the diodes and in case of failure, you can easily test them with a multimeter and determine the faulty diode.

    The lamp consists of ten side plates with six LEDs on each plate. Plus, 12 more diodes are soldered on the top cover. A total of 72 diodes are obtained.

    Let's start disassembling this miracle to quickly see the insides. Before that, you need to carefully examine the body and understand which parts are connected to each other.

    On the top cover you can see parts that fit together; the cover has grooves. That's what we'll be filming. To do this, take a thin screwdriver or knife and carefully pry the lid evenly around the entire perimeter.

    As you can see in the photo there is practically nothing inside. The driver is attached to the wall with double-sided tape. The side plates can be easily pulled out of the grooves. There are a lot of connecting wires around.

    In the depths you can see the wires through which the power supply voltage 220 Volt from the base to the driver input. There are two wires coming out of the driver (red and white). LEDs are connected to them.

    I decided to measure the voltage at the driver output. Multimeter shows voltage 77 volts (DC). Connection diagram for all diodes performed parallel-serial. A group of three diodes connected in parallel is connected in series with another group, and so on. In total there are 24 “links” of “three diodes”.

    Here is a simple device for a 220 Volt LED lamp of the “corn” type.

    I didn't like the fact that this lamp does not have a radiator. And as you know, friends, the main problem with LEDs is heating and heat dissipation. There are no metal objects in it at all, with the exception of the boards on which the diodes themselves are soldered; they are made of aluminum. The case is made of ceramic, there are four ventilation holes near the base.

    I don't know if this is good or bad. Maybe you can tell me, friends, write in the comments.

    We disassemble the LED lamp “Housekeeper”

    The next LED lamp that I want to disassemble and show you its structure is the “Housekeeper”, with a power of 7 W. She has been serving me faithfully for two years now. Technical characteristics are presented in the photo.

    Like the previous lamp, the base size is E27. The base itself is attached to the body with special in-depth grooves. It is impossible to remove it without drilling or other damage.

    The lamp body is made of aluminum and has a structural shape resembling a basket. There are ribs on the sides for air circulation and additional heat removal.

    This lamp has a hemispherical diffuser made of matte plastic. Unlike the previous version, where everything is cowardly and held together, here everything is assembled very well, in fact - one monolithic structure.

    How to disassemble an LED lamp of this type? Here the insides are hidden behind the diffuser. We take a screwdriver with a thin tip and pry off the flask.

    An aluminum plate with SMD 5730 diodes is fixed in the center on three bolts. There are 14 diodes. In my opinion, all the LEDs are connected in series. I can’t say for sure, since the connecting tracks on the board are invisible. If one of them fails, the lamp will stop working.

    Thermal paste is applied at the contact point between the board and the metal case ( white, the structure resembles ordinary silicone sealant).

    By unscrewing three screws and lifting the board, you can see the main thing - the driver.

    The driver is compactly located in the central tube.

    Let's measure what voltage the driver produces. The multimeter shows voltage within 44 Volts.

    The lamps use LEDs as a light source. LED lamps are used for street lighting, in industry and in everyday life. These are the cleanest lighting sources from an environmental point of view.

    Their safety is based on the use of non-hazardous components in the manufacture. No mercury is used, so LED bulbs are not dangerous if they burn out or break.

    Device, principle of operation

    The main components of an LED lamp are:

    • Frame.
    • Base.
    • Driver.
    • LEDs.

    A light-emitting diode is designated by the letter abbreviation LED or SD. On English its designation is LED. It is part of the LED lamp as a light source.

    The scheme of its operating principle coincides with the process of any semiconductor diode made of germanium or silicon with p-n junction. When a positive potential difference is applied to the anode and a negative potential difference to the cathode, electrons move towards the anode and holes move towards the cathode. The current flows straight through the diode in one direction.

    But, in the composition of other materials from semiconductors, when bombarded in the forward direction by holes and electrons, they carry out recombination, transferring them to the next energy level. As a result, photons are released, which are elementary particles of light wave radiation.

    In electrical circuits, LEDs are designated as ordinary diodes, and arrows are added to them (light emission).

    Semiconductors have different photon-emitting properties. Straight-gap conductors—the substances gallium nitride and gallium arsenide—are transparent to light waves in the visible spectrum. The release of light occurs as a result of replacement layers р-n transition.

    In an LED, the layers are located:

    1 - Anode
    2 - Cathode
    3 - Active layer based on In-GaN
    4 - GaN-based buffer layer
    5 - Sapphire substrate
    6 - Conducting n-GaN layer
    7 - Current-conducting p-GaN layer

    There are contact pads in the layers for the cathode and anode.

    When electrons transform into photons, energy is lost for the following reasons:

    • Light waves are refracted at the exit from the semiconductor at the crystal-air location, the wavelength is distorted.
    • Inside the layer, some light particles are lost, although the layer is very thin.

    The luminous flux can be increased if a sapphire substrate is used. Such designs have found application in lamps. In conventional LEDs, a substrate is not used for indicators.

    Such diodes have a lens made of a reflector that directs the light and epoxy resin. According to the purpose of the lamp, the angle of light propagation has a wide range from 5 to 160 degrees.

    Expensive diodes for lamps are produced with a Lambertian diagram, that is, the brightness of the LED in space is constant, regardless of the angle or direction of the light.

    The crystal dimensions are small; there will be little light from one crystal. The lamps contain a group of LEDs. It is difficult to make lighting uniform, since each diode is a point light source.

    1 - Pin 1
    2 - Housing
    3 - CHIP
    4 - Phosphor layer
    5 - Explorer
    6 - Reflector
    7 - Conclusion 2
    8 - Heat sink
    9 - Insulator
    10 - Printed circuit board

    The narrow spectrum of light waves from semiconductor diodes leads to eye fatigue and discomfort, unlike the sun or incandescent lamps. To somehow correct this drawback, a phosphor layer was introduced into the design of the LEDs.

    Size of light emitted semiconductor diode, depends on the strength current p-p transition. With a higher current, the radiation is higher, up to a certain threshold.

    The dimensions of LEDs are small, so it is not possible to use large currents. The current for indicator diodes does not exceed 20 mA. For more powerful lighting lamps, heat removal and protective measures are taken, which have limitations.

    The light flux in the lamp increases as the current increases, then decreases due to heat loss. No heat is generated when an LED lamp is illuminated; they are considered cold light.

    But this does not mean that the lamp does not heat up. Current passing through the LED, in various contacts passes through the resistance sections, which causes the lamp to heat up. Energy is lost due to heat, and when the current increases, the heat can damage the design of the LED lamp.

    LED crystals in lamps can reach a large number (more than 100). To supply the optimal current, boards are made of fiberglass with tracks that conduct current and have different configurations.

    LED crystals are soldered to the contact pads in groups, power is supplied sequentially, and the same current is passed through each chain. This scheme is simple in technical terms, but has serious drawback. If any contact is broken, then all the links in the chain stop shining and the lamp fails.

    Each group of diodes is supplied with a constant voltage from the driver device. Previously it was called a power source. The driver converts the network input voltage into the supply voltage of the LEDs. The input voltage can be either 220 V (in an apartment) or 12 V (in a car).

    It is difficult to connect a stabilized direct current to each LED in parallel and is rarely used. Drivers have various schemes: transformer, etc. Common circuit options depend on the configuration.

    Drivers have a low cost provided that they are connected to a constant voltage that is protected from surges, surges and pulses, and do not have a current-limiting resistor in the power output circuit. This is used in battery-powered flashlights, in which the LEDs are connected to batteries.

    They are powered by high current, shine brightly, and burn out quite often. If the drivers do not have protection against voltage surges, then cheap lamps will quickly burn out without reaching their service life under warranty.

    Power supplies high quality workmanship do not heat up, overloaded drivers heat up, energy is spent on heat loss. These losses are quite significant; they can exceed the energy of the emitted photons (light).

    LED apartment lamps have an E27 base. It makes it possible to use lamps in conventional sockets. Imported lamps are equipped with different sockets, which require appropriate sockets, with differences in thread pitch and diameter. The supply voltage can be 110 V. Lamps for cars also come in different socket designs.

    To protect LEDs, you do not need sealed bulbs, you do not need to pump air out of them or create a gas environment. The LEDs are covered with plastic materials that transmit light.

    The placement of parts on LEDs differs among manufacturers for different purposes. The installation sequence is the same: from the driver to the LED board, closes protective glass. Heat protection screens, etc. can be installed.

    Device and design features different manufacturers may differ significantly in similar lamps, but their design principles are common.

    Types and applications of LED lamps

    Based on their application, LED lamps are divided into:

    • For home and office.
    • Street.
    • Spotlights.
    • Automotive.
    • LED lamps for plants (ultraviolet).
    • Lamps for buildings.

    Based on their design and luminous flux, LED lamps are divided into:

    • General purpose, for offices and residential premises, similar to incandescent lamps, candles, “corn” lamps.
    • Directional light - for illuminating shop windows and squares.
    • Linear, tube-shaped, similar to fluorescent lamps. Suitable for sales areas and offices.

    By types of LEDs used:

    • Indicator diodes. These include lamps with 3 mm diodes and Piranhas. The quality of light from such lamps is low.
    • SMD diodes are common, small in size, do not heat up, and are widely used.
    • Diodes 1, 3, 5 W, heating is significant.
    • SOV diodes, by new technology, advantages over others: more reliable due to the installation of diodes directly on the board, uniform luminous flux, different lamp shapes.
    • Filament diodes, 360 degree lighting, low price, heat sink.
    Separation by type of base


    Edison sockets with threads and the designation beech E with a number are widespread. The number is the diameter of the base in mm (E27, E14, E40). Base G – pin connection. The number indicates the distance between the pins (terminals). Such lamps are connected only through a power supply. The T socket is used to replace fluorescent lamps, measured in inches.

    Advantages, disadvantages, features

    The advantages include:

    • Energy saving, energy efficiency, consume 5 times less energy.
    • Service life is for different types 30-50 thousand hours of work.
    • Mechanical strength.
    • Safety, do not contain harmful substances, no strong heating, used in any lamps, for suspended ceilings.
    • Wide temperature range of use, work down to -60 degrees below zero.
    • Quick start, shine brightly immediately.
    • Reliability with frequent switching off and on.
    • Environmentally friendly, can be disposed of with regular waste.

    The disadvantages include:

    • Large sizes due to the technical side of the device.
    • They are afraid of overheating, efficiency decreases, and they become dull.
    • They may not fit into any chandelier due to the increased size.
    • The luminous flux is directional; it shines worse on the sides and behind.
    • The cost is higher than other types of lamps, the price decreases every year.

    Peculiarities

    LED lamps consist of a board with LEDs, a base, a housing, a power supply, and a matte bulb. The current is immediately converted into light, bypassing the heating stage, as in incandescent lamps. Heating losses are minimal, LEDs are economical and safe.

    LEDs were invented back in the 70s, but were used only in instruments, indicators, and screens. LEDs blue color high-brightness manufactured in 1993, white in 1996. Modern LEDs have a light output of up to 170 lm/W.

    Before our eyes, a real revolution in lighting is taking place: the world is rapidly switching to LEDs. Just five years ago LED lamps were still around technical novelty, and now LED lighting used in all areas of life: led lights can be found even in villages, many offices, hotels and public buildings are illuminated with LED lamps, the vast majority of concert and theater lighting has become LED. Lamps of this type also appear in many apartments, because they can be bought even in grocery stores, and in household goods their range is wider than other types of lamps.

    LED lamp is quite complicated electronic device with several dozen details on which the quality of light, its safety for health and the durability of the lamp depend.

    ⇡ Pros and cons

    LED lamps have many advantages compared to conventional incandescent lamps:

    • Economical - with the same amount of light, a modern LED lamp consumes 7-10 times less electricity.
    • Durability - an LED lamp lasts 15-50 times longer than a conventional one.
    • A little heating - the child will not get burned on the LED lamp in the table lamp.
    • Same brightness at different mains voltages - unlike incandescent lamps, LED lamps shine just as brightly at lower mains voltages.
    • The ability to install an LED lamp, much brighter than an incandescent lamp, in a lamp that has a power limitation.
    • Light good lamps visually indistinguishable from incandescent light.

    There are also advantages when compared with compact fluorescent (energy-saving) lamps (CFL):

    • Environmentally friendly - no hazardous substances (the bulb of any CFL contains mercury).
    • Economical - the lamp consumes less energy with the same luminous flux.
    • The LED lamp instantly lights up to full brightness, and the CFL smoothly increases brightness from 20% to 100% in a minute at room temperature and much more slowly at low temperatures.
    • CFLs have a poor spectrum consisting of peaks of several colors. The spectrum of an LED lamp is much closer to natural light and incandescent light.

    But, of course, there are also disadvantages:

    • High price.
    • Presence on the market of lamps with poor quality light (pulsation, bad color characteristics, uncomfortable color temperature, inconsistency luminous flux and the equivalent of an incandescent lamp as declared).
    • Some lamps have problems with switches that have an indicator.
    • Only some expensive models support brightness adjustment (dimming).

    Let's figure out the savings

    The main advantage of LED lamps is energy savings. For the same amount of light emitted by the lamp, an LED lamp consumes 7-10 times less electricity than a conventional incandescent lamp. You can now buy 6-watt LED bulbs and 4-watt LED bulbs, which provide the same amount of light as a 60- and 40-watt incandescent bulb, respectively.

    I calculated what the electricity costs would be when lighting a two-room apartment with conventional and LED lamps. Of course, this is an approximate calculation, but it allows you to get an idea of ​​the order of the numbers of possible savings.

    The packaging of any incandescent lamp indicates a service life of 1,000 hours. If the lamps actually work for 1,000 hours (unfortunately, they often burn out much earlier), the lamps in the hallway and room will have to be changed twice a year, and in the kitchen and bedroom once. If a lamp costs 30 rubles, it will cost 690 rubles to buy new lamps. LED lamps do not have to be changed every six months, because their service life is 15-50 thousand hours. This is from 7 to 22 years when used 6 hours a day.

    The purchase of lamps for this apartment will cost 4,045 rubles (7 E27 6 W lamps for 240 rubles, 11 “candles” 4 W for 215 rubles), and they will pay off in less than a year.

    LED and energy saving lamps

    LED bulbs are undoubtedly energy efficient, but the word "energy efficient" is attached to compact fluorescent lamps (CFLs), and CFLs and LED bulbs are very different things.

    CFLs became widely available about ten years ago and were expected to replace incandescent lamps. However, CFLs turned out to be a dead-end branch of evolution. These lamps have many disadvantages: the lamp tube contains mercury, the lamp lights up slowly and does not shine at all in the cold, CFLs have a poor spectrum, consisting of peaks of several colors.

    From July 1, 2016, in accordance with Decree of the Government of the Russian Federation No. 898 of August 28, 2015, all state and municipal enterprises and institutions will be prohibited from purchasing any lamps containing mercury (including CFLs) through the public procurement system. Already, the number of CFLs in stores is constantly decreasing, and soon they will disappear completely.

    Let's compare the light spectrum of an incandescent lamp, a fluorescent lamp and an LED lamp.

    The spectrum of an LED lamp is much closer to natural light and incandescent light.

    A little history

    The glow of a semiconductor junction was first discovered in 1923 by the Soviet physicist Oleg Losev. The first LEDs were called "Losev Light" (Losev's light). First the red LED appeared, then yellow and green LEDs appeared in the early 70s. The blue LED was created in 1971 by Yakov Panchechnikov, but it was very expensive. In 1990, Japanese Suji Nakamura created a cheap and bright blue LED.

    After the advent of the blue LED, it became possible to make white light sources with three crystals (RGB). Such sources are still used in concert and decorative lighting.

    In 1996, the first white LEDs using a phosphor appeared. In them, blue or ultraviolet LED light is converted to white using a special chemical applied on top of light-emitting crystals.

    Phosphor LED

    In 2005, the efficiency of such LEDs reached 100 lm/W, which made it possible to begin using phosphor LEDs for lighting. Now the most efficient white LEDs already produce 200 lm/W, commercial lamps with standard sockets - up to 125 lm/W.

    Types of LED lamps

    LED lamps replicate all possible types of incandescent, halogen and fluorescent lamps. We produce ordinary lamps - "pears", "candles" and "balls" with E27 and E14 sockets, "mirror" lamps R39, R50 with E14 sockets, and R63 with E27 sockets, spots with GU10 and GU5.3 sockets, capsule microlamps with sockets G4 and G9, lamps for ceilings with socket GX53.

    What are LEDs?

    Light emitting diode (LED) is semiconductor device, transformative electric current into light radiation and consisting of a semiconductor crystal on a substrate, a housing with contact leads and optical system. Modern LEDs bear little resemblance to the first packaged LEDs used for display.

    What are the advantages of LED?

    In an LED, unlike an incandescent or fluorescent lamp, electric current is converted directly into light radiation, and theoretically this can be done with almost no loss. With proper heat dissipation, the LED heats up little, which makes it indispensable for some applications. Further, the LED emits in a narrow part of the spectrum, its color is pure, which is especially appreciated by designers, and UV and IR radiation are usually absent. The LED is mechanically strong and extremely reliable, its service life can reach 100 thousand hours, which is almost 100 times longer than an incandescent light bulb and 10 times longer than a fluorescent lamp. Finally, the LED is a low-voltage electrical device, and therefore safe.

    How to get white light using LEDs?

    There are three ways to produce white light from LEDs. The first is color mixing using RGB technology. Red, blue and green LEDs are densely placed on one matrix, the radiation of which is mixed using an optical system, such as a lens. The result is white light. The second method is that three phosphors are applied to the surface of an LED emitting in the ultraviolet range (there are some), emitting blue, green and red light, respectively. It's similar to how a fluorescent lamp shines. Finally, in the third method, a yellow-green or green plus red phosphor is applied to a blue LED so that the two or three emissions mix to form white or near-white light.

    What are the electrical and optical characteristics LEDs?

    LED is a low voltage device. A conventional LED used for indication consumes from 2 to 4 V DC voltage at currents up to 50 mA. The LED used for lighting consumes the same voltage, but the current is higher - from several hundred mA to 1 A in the project. In an LED module, individual LEDs can be connected in series and the total voltage is higher (usually 12 or 24 V).

    When connecting an LED, the polarity must be observed, otherwise the device may be damaged. The breakdown voltage is specified by the manufacturer and is usually more than 5 V for a single LED. The brightness of an LED is characterized by luminous flux and axial luminous intensity, as well as by the directional pattern. Existing LEDs of various designs emit solid angles from 4° to 140°. Color, as usual, is determined by chromaticity coordinates and color temperature, as well as the wavelength of the radiation.

    To compare the efficiency of LEDs with each other and with other light sources, luminous efficiency is used - the amount of luminous flux per watt electrical power. Another interesting marketing characteristic is the price per lumen.

    Why do you need to stabilize the current through the LED?

    In operating conditions, current varies exponentially with voltage and small changes in voltage lead to large changes in current. Since the light output is directly proportional to the current, the brightness of the LED is unstable. Therefore, the current must be stabilized. In addition, if the current exceeds the permissible limit, overheating of the LED can lead to accelerated aging.

    Can the brightness of the LED be adjusted?

    The brightness of LEDs can be very well adjusted, but not by reducing the supply voltage - this is something that cannot be done - but by the so-called pulse-width modulation (PWM) method, which requires a special control unit (in reality, it can be combined with the power supply and converter, as well as with an RGB matrix color control controller). The PWM method consists in the fact that not a constant, but a pulse-modulated current is supplied to the LED, and the signal frequency should be hundreds or thousands of hertz, and the width of the pulses and pauses between them can vary. The average brightness of the LED becomes controllable, while at the same time the LED does not go out. The slight change in LED color temperature when dimming is incomparable to the same shift for incandescent lamps.

    What determines the lifespan of an LED?

    LEDs are said to be extremely durable. But this is not entirely true. The more current passed through an LED during its service, the higher its temperature and the faster aging occurs. Therefore, the service life powerful LEDs shorter than that of low-power signal signals, and currently amounts to 20 - 50 thousand hours. Aging is expressed primarily in a decrease in brightness. When the brightness decreases by 30% or half, the LED must be replaced.

    Is LED harmful to the human eye?

    The emission spectrum of an LED is close to monochromatic, which is its fundamental difference from the spectrum of the sun or an incandescent lamp. Whether this is good or bad is not known for certain, because serious research in this area has not been conducted anywhere. Any information about harmful effects There are no LEDs for the human eye. It is hoped that soon the effect of LEDs on vision will be studied in detail.

    Where is it advisable to use LED products today?

    LEDs are used in almost all areas of lighting technology; they are indispensable in designer lighting due to their pure color, as well as in dynamic lighting systems. It is advantageous to use them where frequent maintenance is expensive, where it is necessary to strictly save energy, and where electrical safety requirements are high.

    Which LEDs are better?

    Of course, there can be no clear answer to such a question. Nowadays, LED manufacturers can be compared to car manufacturers. After all, all of them have cars on four wheels, equipped with an engine, airbags and a car radio! But to compare them, numerous technical characteristics are compared, and it is not unfoundedly stated that BMW is better than Lexus or Audi is better than Volvo.

    When choosing LEDs, you need to pay attention to the following characteristics, which are usually binned (BIN) into groups:

    • brightness (60-70 Lm, 70-80 Lm, 80-90 Lm);
    • angle (80°-90°, 90°-100°, 100°-110°);
    • color temperature (5000-5500K, 5000-6000K, 5000-7500K, 5000-10000K);
    • voltage (2.8-3V, 2.8-3.2V, 2.8-3.6V).

    The better the LEDs are combined, the more uniform their characteristics will be, which means the more reliable the final product will be. And it should be noted that the smaller the BIN range, the more expensive the LED (after all, LEDs in this case have to be sorted).

    Accordingly, to answer the question which LEDs are better, it is necessary to compare similar types with similar ones technical characteristics and their compliance with the declared BINs from the manufacturers.

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