1 LED. Characteristics of LEDs: main parameters and distinctive features. Main brands

Crystal glow

Quite often people have to buy 1 W and 3 W LEDs. If we do this in trusted stores, then there is no big problem. What if we do this at new sites? How not to be deceived? How to distinguish 1 W LEDs from 3 W? In principle, the task is not impossible... Let's see and try...

I won’t discuss what powerful 3 W and 1 W LEDs are. If you are reading this material, then it seems to me that you understand quite well what is what. Why and for what purpose did you buy it?

Comparison of two LEDs 1 W and 3 W

Left 1 W Right 3 W

A visual comparison of two LEDs will not give you practically any information if you have never encountered this before. More advanced people can distinguish by eye which LED will be more powerful and which will not, by examining the crystal. But it will not always be possible to do this visually. The crystal is not always visible.

To determine which LEDs are 1 W or 3 W lying on the table, it is worth conducting some measurements and experiments.

Characteristics of 1 W and 3 W LEDs

I took LEDs from a local store (origin unknown) and a diode purchased on Aliexpress. According to the sellers, both are 3 W.

Let's look at the characteristics of 1 and 3 W LEDs. Let's take the most popular ones from Epistar. LEDs from other manufacturers, in principle, do not differ from these data.

Characteristics of 3 W and 1 W LEDs

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Characteristics of 1 W LED


We see that the operating current of 1 W diode is 350 mA, 3 W - 700 mA. The maximum peak current for both is 0.8 A. That is. both of these diodes will operate at the maximum possible 0.75A. They will work at 1 A, but not for long). You shouldn't overclock chips unnecessarily; we still care about durability. Moreover, if you purchased the right LED, then the brightness will be enough for you.

How to distinguish between 3W and 1W LEDs

When the chips are turned on at full power, you will hardly be able to distinguish 1 W and 3 W by light. The eye will not perceive too bright a glow.

You can use a black box, turn on the LEDs individually and see which sample gives the greater lighting effect. Instead of a box, you can use a black sheet. This is an example, but the meaning is clear, I think.

If you have two diodes of unknown origin, then you can determine which of them is 3 W and which is 1 W in the following way: connect both to the power source and apply 3.5 V to them. In this case, the initial current value should be within 350mA. Let's look at the graphical dependence of brightness on current.

Dependence of 1 and 3 W LEDs on current

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Dependency graph of 1 W diode

Graph of 3 W diode

With an increase in the initial voltage of 3.5 V, the brightness of the 1 W diode will increase slightly and practically stop if the voltage (current) is further increased. If you have a 3 W diode, then as the voltage increases from 3.5 V, the current will increase, and according to the graph above, we see that the brightness will gradually increase until the current reaches 700 mA.

Graph of current versus voltage of 1 and 3 W LEDs

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Dependence of current on voltage 1 W


Dependence of current on voltage of 3 W diode

Those. visually we can determine any LED 1 W or 3 W if we apply a current of 350 mA to it and gradually increase it. An increase in brightness from 350 mA indicates that we have a 3 W diode. A slight increase in brightness from 350 to 700 mA indicates that we have a 1 W diode.

Another way to determine whether a 3W or 1W LED is powerful is by heating. It's simple physics. At the same 350 mA 1 W, the LED will heat up quickly. And you won’t be able to hold it in your hand. A 3 W LED at the same current can be held in your hand for a long time without noticeable discomfort. Naturally, this is a side way of determining which diode is which. But it has a right to exist.

Well last method- distinguish LEDs by crystal size. To be sure to do this, you should purchase a USB microscope. This a budget option and of sufficient quality, with the necessary gadgets. You can look at many microscopes of different price categories. In general, a USB microscope is an interesting contraption and will come in handy at home more than once. Then, using a calibration ruler and a preset program, you can easily measure the dimensions of the crystal. With it we can tell exactly what crystal size is installed. However, this method will not give us an exact idea of ​​which diode is which. But taking into account that the larger the crystal, the greater the power, you can draw a conclusion for yourself accordingly.

Powerful 1 W diodes have dimensions of 30x30mil. Crystals in 3 W diodes - 45x45mil. These are, of course, the ideal sizes.

If you don’t have a microscope, but want to know the dimensions, then you can use improvised means. Let's apply a very small current to the LEDs. The crystals will begin to glow faintly.

Crystal glow

On the left we see that the crystal size is an order of magnitude larger. This particular LED was purchased on Aliexpress. The sample that was purchased in an offline store is clearly 1 W, despite the fact that it was sold with a declared power of 3 W. In principle, one look at the crystal through a microscope was enough for me to understand where the diode would be. But for my beloved self, I checked the glow using the first method (increasing the current) and the visual conclusion was confirmed.

OK it's all over Now. In these simple ways, you can now safely check, compare and distinguish between 3 W and 1 W powerful LEDs. But in order not to do this all the time, it is worth purchasing LED products from trusted stores and sites.

Video on measuring crystals to distinguish between 1 and 3 W LEDs

A 1 watt LED is an example of a powerful lighting source. Its sales are increasing as people realize the benefits of using an LED fixture.

Advantages of a powerful 1 watt LED:

  • service life up to 50 thousand hours without significant loss of lighting quality;
  • bright light, high efficiency;
  • resistance to mechanical damage;
  • instantly lights up and goes out;
  • does not flicker;
  • high degree of light directionality.

Using 1-watt LED sources, you can create energy-saving lighting systems. After all, there is only one lighting fixture Replaces several incandescent lamps. In addition, it does not contain components harmful to health and does not require large disposal costs.

Prevent overheating

One of the problems in the manufacture of high-power LEDs for 1 W, 3 W, etc. is the issue of heat dissipation. The emitting semiconductor is very sensitive to overheating, so it is necessary to provide cooling during its operation.

Heat is removed by fixing the LED on a special radiator - a flat aluminum substrate, the temperature of which should not exceed 45 degrees. The substrate helps simplify installation, since it is convenient to make holes in it for fastening and it is convenient to solder it.

Regularly overheating an LED by 1 W will shorten its service life. If you purchased a crystal without a substrate and are going to mount it yourself, it is recommended to choose an aluminum panel with an area of ​​25 cm2. or more. This is a 5 by 5 mm plate. It is desirable that air circulates at least a little around it.

Main characteristics

The voltage drop across a powerful 1 W LED producing white light is usually 3-3.5 volts. Power is gained due to increased current up to 300-350 mA. To ensure proper power supply, LEDs are assembled in a circuit with a resistor or connected through drivers. The task when assembling a circuit is to ensure a stable voltage and current that does not exceed the maximum permissible value.

The most popular are powerful 1 W LEDs for surface mounting. There is a “star” version of them. This is a heat sink plate made in the shape of a star. It has pads for contacts, so working with this design is very convenient.

Among the light temperatures, daylight white, soft white and bluish tints are preferred, although there are models on the market that emit a variety of shades of blue and yellow-red, as well as green light.

Color rendering is very high (more than 80%). The luminous flux can reach 100 lumens, which is equivalent to the luminous flux from a 15-watt incandescent lamp.

Modern 1-watt models are used to illuminate furniture, interiors of cars and buses, and for interior and exterior lighting of homes. They are inserted into impact-resistant flashlights that can be powered by regular batteries.

Main brands

Sometimes they meet negative reviews about LEDs, in which they write about low lighting and rapid failure. When you pay a significant amount for a powerful LED of 1 or more watts, and after a couple of weeks it begins to shine noticeably worse, you really feel sorry for the money spent.

The fact is that the production of LED crystals is an expensive process that requires strict adherence to technology. During the assembly of devices, chips are tested and sorted. There are quite a few companies in the world engaged in this process.

By purchasing an LED of dubious manufacture, you risk purchasing a 1-watt lighting device with a defective or simply low-quality chip. Therefore, it is recommended to buy LEDs only from well-known brands or contact a trusted supplier who tests the product and is responsible for what he offers you.

Today there are several large manufacturers engaged in research and having their own developments. They definitely value their reputation:

  • OSRAM (Germany) with a fairly wide range of models;
  • Lumileds Philips (Holland, but headquartered in the USA) brand LUXEON;
  • CREE (USA center);
  • Avago Technologies(Singapore);
  • SEOUL (South Korea);
  • NICHIA (Japan).

Assembly can be carried out in Malaysia, China, Taiwan, Europe and America. If you buy a genuine product (not a fake or imitation) from one of these brands, you can be confident in their quality.

The development of the industry has led to the fact that the characteristics of LEDs of 1 watt or more have almost leveled off. This allows customers not to be tied to a specific brand, but to choose LEDs based on their cost and ease of delivery.

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Main characteristics of SMD 5730 LEDs

Modern products with geometric parameters 5.7×3 mm. Due to their stable characteristics, SMD 5730 LEDs belong to the category of ultra-bright products. New materials are used for their manufacture, due to which they have increased power and highly efficient luminous flux. SMD 5730 allows operation in conditions of high humidity. They are not afraid of vibration and temperature fluctuations. They have a long service life. They have a dispersion angle of 120 degrees. After 3000 hours of operation the degree does not exceed 1%.

Manufacturers offer two types of devices: with a power of 0.5 and 1 W. The first are marked SMD 5730-0.5, the second - SMD 5730-1. The device can operate on pulsed current. For SMD 5730-0.5, the rated current is 0.15 A, and when switching to the pulsed operating mode it can reach 0.18 A. It is capable of generating a luminous flux of up to 45 Lm.

For SMD 5730-1, the rated current is 0.35A, pulse current can reach 0.8A with a light output efficiency of 110 Lm. Thanks to the use of heat-resistant polymer in the production process, the device body is not afraid of exposure to fairly high temperatures (up to 250°C).

Cree: current characteristics

The products of the American manufacturer are presented in a wide range. The Xlamp series includes single-chip and multi-chip products. The former are characterized by the distribution of radiation along the edges of the device. This innovative solution made it possible to launch the production of lamps with a large luminous angle with a minimum number of crystals.

The XQ-E High Intensity series is the company's latest development. The products have a glow angle of 100-145 degrees. With relatively small geometric parameters of 1.6 by 1.6 mm, such LEDs have a power of 3 V with a luminous flux of 330 lm. The characteristics of Cree LEDs based on a single crystal make it possible to provide high-quality color rendering CRE 70-90.

Multi-chip LED devices have the latest type of power supply 6-72 V. They are usually divided into three groups depending on the power. Products up to 4 W have 6 crystals and are available in MX and ML packages. The characteristics of the XHP35 LED correspond to a power of 13 W. They have a dispersion angle of 120 degrees. Can be warm or cold white.

Checking an LED with a Multimeter

Sometimes it becomes necessary to check the performance of an LED. This can be done using a multimeter. Testing is performed in the following sequence:

PhotoDescription of work
Cooking necessary equipment. A regular Chinese multimeter model will do.
We set the resistance mode corresponding to 200 Ohms.
We touch the contacts to the element being checked. If the LED is working, it will start to glow.
Attention! If the contacts are swapped, the characteristic glow will not be observed.

LED color marking

To purchase an LED of the desired color, we suggest that you familiarize yourself with the color symbol included in the marking. For CREE, it is located after the designation of a series of LEDs, and can be:

  • WHT, if the glow is white;
  • HEW, if high efficiency white;
  • BWT for white second generation;
  • B.L.U., if the glow is blue;
  • GRN for green;
  • ROY for royal (bright) blue;
  • RED at red.

Other manufacturers often use a different designation. So KING BRIGHT allows you to choose a model with radiation not only of a certain color, but also of shade. The designation present in the marking will correspond to:

  • Red (I, SR);
  • Orange (N, SE);
  • Yellow (Y);
  • Blue (PB);
  • Green (G, SG);
  • White (PW, MW).
Advice! Acquainted with symbols specific manufacturer to make the right choice.

Decoding the LED strip marking code

To manufacture the LED strip, a dielectric with a thickness of 0.2 mm is used. Conductive tracks are applied to it, having contact pads for chips intended for mounting SMD components. The tape includes individual modules 2.5-10 cm long and designed for a voltage of 12 or 24 volts. The module may include 3-22 LEDs and several resistors. The average length of finished products is 5 meters with a width of 8-40 cm.

Markings are applied to the reel or packaging, which contains all the relevant information about LED strip. The explanation of the markings can be seen in the following figure:

Article

    Thanks Dima. Yes, the difference is huge no matter how you look at it. One thing is not clear how a 9 watt lamp can show only 3.5. In my opinion, even if you put 10 3-watt LEDs in a lamp, it will not shine like a 300-watt lamp. And the Chinese think so. Here you have an LED hanging on the ceiling, there is only one, and it’s really 50 watts, there are no questions about it at all, it works out its 50 watts.
    In general, the luminous flux of LEDs can only illuminate a certain space. This is what we need to proceed from. The Chinese have thought through everything to the smallest detail. We take the space of the apartment and divide it into the space that can be illuminated by a 3-watt LED and get the number of LEDs necessary for full lighting. I think there will be a lot of them needed.

    • I agree that we are being misled, and people simply do not know what information to take when choosing lamps, since there is no concept that one hundred watts is precisely the consumption of one hundred watts and not the light power.

      • This is why lumens were invented instead of candelas, to mislead people.
        1 candela (candle) - a clear amount of light, uniform over the entire radius of the glow.
        1 lumen is a characteristic of a ray (beam) of light.

        If we could collect the light from a candle into a bunch (or more precisely, a “beam”), then we would get a laser powerful enough to light a candle at a fairly large distance.

    It’s somehow not right to compare like this, it’s not for nothing that their supply voltages are indicated with a spread. For one, 3.3V is enough, but for another it may not be enough and different currents flow through them. (if you test like this, then at least include an ammeter in the circuit to calculate the wattage)
    You need to power it from a driver, for example 350mA, and at the same time measure the voltage on them. one can consume 3V*350mA=1.05W, and the other 3.8V*350mA=1.33W. Accordingly, the brightness will be different.

      • Supply voltage - this parameter is not applicable for the LED. LEDs do not have this characteristic, so you cannot connect LEDs to a power source directly. The main thing is that the voltage from which the LED is powered (through a resistor) is higher than the direct voltage drop of the LED (the forward voltage drop is indicated in the characteristics instead of the supply voltage and for conventional indicator LEDs it ranges on average from 1.8 to 3.6 volts).
        The voltage indicated on the LED packaging is not the supply voltage. This is the amount of voltage drop across the LED. This value is necessary to calculate the remaining voltage that has not “dropped” on the LED, which takes part in the formula for calculating the resistance of the current-limiting resistor, since it is this that needs to be adjusted.
        A change in the supply voltage of just one tenth of a volt for a conventional LED (from 1.9 to 2 volts) will cause a fifty percent increase in the current flowing through the LED (from 20 to 30 milliamps).

        For each LED of the same rating, the voltage suitable for it may be different. By switching on several LEDs of the same rating in parallel and connecting them to a voltage of, for example, 2 volts, we risk, due to the variation in characteristics, quickly burning some copies and under-illuminating others. Therefore, when connecting an LED, it is necessary to monitor not the voltage, but the current.

        • Somehow we are not talking about the same LEDs, mine, for example, take the same current and they are at least 5. But let’s consume as much as it needs.
          But the voltage at the same current increases its brightness and reduces its lifetime.

          • Hmm, I certainly apologize, but with all due respect to your practical studies, it wouldn’t hurt to learn some theory. Voltage is applied, and current flows in the circuit; at 5A it will immediately burn out through the diode. Google “LED driver”.
            a device that, by regulating voltage, maintains a constant current in the circuit. They are just standing inside LED lamps, for example 9-12V at 350mA in a 3-diode.

            As a visual experiment, I propose to supply 3.3V to the lights from one box without reduction. You can also connect an ammeter in series. You will be surprised by the different brightness of the glow (different currents in the circuit)

            PS in these Ketai supposedly 12W lamps there are 1W LEDs.

    Author, for the sake of fact, you say that even a 1W LED does not heat up well, it heats up over 100 degrees without a radiator, and for such an operating time as yours it would not only lose efficiency, but could melt or burn out, and this is a fact and not an assumption. In your case, this is not a performance test, but a performance check.

    First, you need to apply a voltage of 3-3.3V not at idle, but UNDER LOAD and achieve 300mA (usually 300mA, less often 350mA) for a 1W LED, then try holding it in your hand!

    And your branding of the product is also in doubt. I bought 100 of the same 1W LEDs for $8 - oh..but bright lights, and assembled a 7W table lamp. And in the photo I saw an LED light bulb with a golden radiator (article about a switch with a motion sensor) I had 3x1W LEDs and a 2W driver, I think it’s the same for you. What I mean is that Chinese lights will also give your branded ones a head start. If you have a lux meter, please measure it and we will compare!

The times when LEDs were used only as indicators for turning on devices are long gone. Modern LED devices can completely replace incandescent lamps in household, industrial and. This is facilitated by the various characteristics of LEDs, knowing which you can choose the right LED analogue. The use of LEDs, given their basic parameters, opens up a wealth of possibilities in the field of lighting.

A light-emitting diode (denoted as LED, LED, LED in English) is a device based on an artificial semiconductor crystal. When an electric current is passed through it, the phenomenon of emission of photons is created, which leads to a glow. This glow has a very narrow spectral range, and its color depends on the semiconductor material.

LEDs with red and yellow emission are made from inorganic semiconductor materials based on gallium arsenide, green and blue ones are made on the basis of indium gallium nitride. To increase brightness luminous flux they use various additives or use the multilayer method, when a layer of pure aluminum nitride is placed between semiconductors. As a result of the formation of several electron-hole (p-n) transitions in one crystal, the brightness of its glow increases.

There are two types of LEDs: for indication and lighting. The former are used to indicate the inclusion of various devices in the network, and also as sources of decorative lighting. They are colored diodes placed in a translucent housing, each of them has four terminals. Devices that emit infrared light are used in devices for remote control devices (remote control).

In the lighting area, LEDs are used that emit white light. LEDs are classified by color into cool white, neutral white and warm white. There is a classification of LEDs used for lighting according to the installation method. The SMD LED designation means that the device consists of an aluminum or copper substrate on which the diode crystal is placed. The substrate itself is located in a housing, the contacts of which are connected to the contacts of the LED.

Another type of LED is designated OCB. In such a device, many crystals coated with phosphor are placed on one board. Thanks to this design, a high brightness of the glow is achieved. This technology is used in production with a large luminous flux in a relatively small area. In turn, this makes the production of LED lamps the most accessible and inexpensive.

Note! Comparing lamps based on SMD and COB LEDs, it can be noted that the former can be repaired by replacing a failed LED. If a COB LED lamp does not work, you will have to change the entire board with diodes.

LED characteristics

When choosing a suitable LED lamp for lighting, you should take into account the parameters of the LEDs. These include supply voltage, power, operating current, efficiency (luminous output), glow temperature (color), radiation angle, dimensions, degradation period. Knowing the basic parameters, it will be possible to easily select devices to obtain a particular illumination result.

LED current consumption

As a rule, a current of 0.02A is provided for conventional LEDs. However, there are LEDs rated at 0.08A. These LEDs include more powerful devices, the design of which involves four crystals. They are located in one building. Since each of the crystals consumes 0.02A, in total one device will consume 0.08A.

The stability of LED devices depends on the current value. Even a slight increase in current helps to reduce the radiation intensity (aging) of the crystal and increase the color temperature. This ultimately leads to the LEDs turning blue and failing prematurely. And if the current increases significantly, the LED immediately burns out.

To limit the current consumption, the designs of LED lamps and luminaires include current stabilizers for LEDs (drivers). They convert the current, bringing it to the value required by the LEDs. In the case when you need to connect a separate LED to the network, you need to use current-limiting resistors. The resistor resistance for an LED is calculated taking into account its specific characteristics.

Helpful advice! To choose the right resistor, you can use the LED resistor calculator available on the Internet.

LED voltage

How to find out the LED voltage? The fact is that LEDs do not have a supply voltage parameter as such. Instead, the voltage drop characteristic of the LED is used, which means the amount of voltage the LED outputs when the rated current passes through it. The voltage value indicated on the packaging reflects the voltage drop. Knowing this value, you can determine the voltage remaining on the crystal. It is this value that is taken into account in the calculations.

Given the use of various semiconductors for LEDs, the voltage for each of them may be different. How to find out how many volts an LED is? You can determine it by the color of the devices. For example, for blue, green and white crystals the voltage is about 3V, for yellow and red crystals it is from 1.8 to 2.4V.

When using a parallel connection of LEDs of identical ratings with a voltage value of 2V, you may encounter the following: as a result of variations in parameters, some emitting diodes will fail (burn out), while others will glow very faintly. This will happen due to the fact that when the voltage increases even by 0.1V, the current passing through the LED increases by 1.5 times. Therefore, it is so important to ensure that the current matches the LED rating.

Light output, beam angle and LED power

The luminous flux of diodes is compared with other light sources, taking into account the strength of the radiation they emit. Devices measuring about 5 mm in diameter produce from 1 to 5 lumens of light. While the luminous flux of a 100W incandescent lamp is 1000 lm. But when comparing, it is necessary to take into account that a regular lamp has diffused light, while an LED has directional light. Therefore, the dispersion angle of the LEDs must be taken into account.

The scattering angle of different LEDs can range from 20 to 120 degrees. When illuminated, LEDs produce brighter light in the center and reduce illumination towards the edges of the dispersion angle. Thus, LEDs illuminate a specific space better while using less power. However, if it is necessary to increase the illumination area, diverging lenses are used in the design of the lamp.

How to determine the power of LEDs? To determine the power of an LED lamp required to replace an incandescent lamp, it is necessary to apply a coefficient of 8. Thus, you can replace a conventional 100W lamp with an LED device with a power of at least 12.5W (100W/8). For convenience, you can use the data from the table of correspondence between the power of incandescent lamps and LED light sources:

Incandescent lamp power, WCorresponding power of LED lamp, W
100 12-12,5
75 10
60 7,5-8
40 5
25 3

When using LEDs for lighting, the efficiency indicator is very important, which is determined by the ratio of luminous flux (lm) to power (W). Comparing these parameters for different light sources, we find that the efficiency of an incandescent lamp is 10-12 lm/W, a fluorescent lamp is 35-40 lm/W, and an LED lamp is 130-140 lm/W.

Color temperature of LED sources

One of the important parameters of LED sources is the glow temperature. The units of measurement for this quantity are degrees Kelvin (K). It should be noted that all light sources are divided into three classes according to their glow temperature, among which warm white has a color temperature of less than 3300 K, daylight white - from 3300 to 5300 K, and cool white over 5300 K.

Note! The comfortable perception of LED radiation by the human eye directly depends on the color temperature of the LED source.

The color temperature is usually indicated on the labeling of LED lamps. It is designated by a four-digit number and the letter K. The choice of LED lamps with a certain color temperature directly depends on the characteristics of its use for lighting. The table below displays options for using LED sources with different glow temperatures:

LED colorColor temperature, KLighting Use Cases
WhiteWarm2700-3500 Lighting for domestic and office premises as the most suitable analogue of an incandescent lamp
Neutral (daytime)3500-5300 The excellent color rendition of such lamps allows them to be used for lighting workplaces in production.
Coldover 5300Mainly used for street lighting, and also used in hand-held lanterns
Red1800 As a source of decorative and phyto-lighting
Green-
Yellow3300 Lighting design of interiors
Blue7500 Illumination of surfaces in the interior, phyto-lighting

The wave nature of color allows the color temperature of LEDs to be expressed using wavelength. The marking of some LED devices reflects the color temperature precisely in the form of an interval of different wavelengths. The wavelength is designated λ and is measured in nanometers (nm).

Standard sizes of SMD LEDs and their characteristics

Considering the size of SMD LEDs, devices are classified into groups with different characteristics. The most popular LEDs with standard sizes are 3528, 5050, 5730, 2835, 3014 and 5630. The characteristics of SMD LEDs vary depending on the size. So, different types SMD LEDs differ in brightness, color temperature, and power. In LED markings, the first two digits indicate the length and width of the device.

Basic parameters of SMD 2835 LEDs

The main characteristics of SMD LEDs 2835 include an increased radiation area. Compared to the SMD 3528 device, which has a round working surface, the SMD 2835 radiation area has a rectangular shape, which contributes to greater light output with a smaller element height (about 0.8 mm). The luminous flux of such a device is 50 lm.

The SMD 2835 LED housing is made of heat-resistant polymer and can withstand temperatures up to 240°C. It should be noted that the radiation degradation in these elements is less than 5% over 3000 hours of operation. In addition, the device has a fairly low thermal resistance of the crystal-substrate junction (4 C/W). The maximum operating current is 0.18A, the crystal temperature is 130°C.

Based on the color of the glow, there are warm white with a glow temperature of 4000 K, daytime white - 4800 K, pure white - from 5000 to 5800 K and cool white with a color temperature of 6500-7500 K. It is worth noting that the maximum luminous flux is for devices with cool white glow, the minimum is for warm white LEDs. The design of the device has enlarged contact pads, which promotes better heat dissipation.

Helpful advice! SMD 2835 LEDs can be used for any type of installation.

Characteristics of SMD 5050 LEDs

The SMD 5050 housing design contains three LEDs of the same type. LED sources of blue, red and green colors have specifications, similar to SMD 3528 crystals. The operating current of each of the three LEDs is 0.02A, therefore the total current of the entire device is 0.06A. To ensure that the LEDs do not fail, it is recommended not to exceed this value.

LED devices SMD 5050 have a forward voltage of 3-3.3V and a light output (mains flux) of 18-21 lm. The power of one LED is the sum of three power values ​​of each crystal (0.7 W) and amounts to 0.21 W. The color of the glow emitted by the devices can be white in all shades, green, blue, yellow and multi-colored.

The close arrangement of LEDs of different colors in one SMD 5050 package made it possible to implement multi-color LEDs with separate control of each color. To regulate luminaires using SMD 5050 LEDs, controllers are used, so that the color of the glow can be smoothly changed from one to another after a given amount of time. Typically, such devices have several control modes and can adjust the brightness of the LEDs.

Typical characteristics of SMD 5730 LED

SMD 5730 LEDs are modern representatives of LED devices, the housing of which has geometric dimensions of 5.7x3 mm. They belong to ultra-bright LEDs, the characteristics of which are stable and qualitatively different from the parameters of their predecessors. Manufactured using new materials, these LEDs are characterized by increased power and highly efficient luminous flux. In addition, they can work in conditions of high humidity, are resistant to temperature changes and vibration, and have long term services.

There are two types of devices: SMD 5730-0.5 with a power of 0.5 W and SMD 5730-1 with a power of 1 W. A distinctive feature of the devices is the ability to operate on pulsed current. The rated current of SMD 5730-0.5 is 0.15A; during pulse operation, the device can withstand current up to 0.18A. This type LEDs provide a luminous flux of up to 45 lm.

SMD 5730-1 LEDs operate at a constant current of 0.35A, in pulsed mode - up to 0.8A. The light output efficiency of such a device can be up to 110 lm. Thanks to the heat-resistant polymer, the device body can withstand temperatures up to 250°C. The dispersion angle of both types of SMD 5730 is 120 degrees. The degree of luminous flux degradation is less than 1% when operating for 3000 hours.

Cree LED Specifications

The Cree company (USA) is engaged in the development and production of ultra-bright and most powerful LEDs. One of the Cree LED groups is represented by the Xlamp series of devices, which are divided into single-chip and multi-chip. One of the features of single-crystal sources is the distribution of radiation along the edges of the device. This innovation made it possible to produce lamps with a large luminous angle using a minimum number of crystals.

In the XQ-E High Intensity series of LED sources, the beam angle ranges from 100 to 145 degrees. Having small geometric dimensions of 1.6x1.6 mm, the power of ultra-bright LEDs is 3 Volts, and the luminous flux is 330 lm. This is one of the newest developments from Cree. All LEDs, the design of which is developed on the basis of a single crystal, have high-quality color rendering within CRE 70-90.

Related article:

How to make or repair an LED garland yourself. Prices and main characteristics of the most popular models.

Cree has released several versions of multi-chip LED devices with the latest power types from 6 to 72 Volts. Multichip LEDs are divided into three groups, which include devices with high voltage, power up to 4W and above 4W. Sources up to 4W contain 6 crystals in MX and ML type housings. The dispersion angle is 120 degrees. You can buy Cree LEDs of this type with white warm and cool colors.

Helpful advice! Despite the high reliability and quality of light, you can buy powerful LEDs of the MX and ML series at a relatively low price.

The group over 4W includes LEDs made from several crystals. The largest in the group are the 25W devices represented by the MT-G series. The company's new product is XHP model LEDs. One of the large LED devices has a 7x7 mm body, its power is 12W, and the light output is 1710 lm. High voltage LEDs combine small dimensions and high light output.

LED connection diagrams

There are certain rules for connecting LEDs. Taking into account that the current passing through the device moves only in one direction, for long-term and stable operation of LED devices it is important to take into account not only a certain voltage, but also the optimal current value.

Connection diagram for LED to 220V network

Depending on the power source used, there are two types of circuits for connecting LEDs to 220V. In one of the cases it is used with limited current, in the second - a special one that stabilizes the voltage. The first option takes into account the use of a special source with a certain current strength. A resistor is not required in this circuit, and the number of connected LEDs is limited by the driver power.

To designate LEDs in the diagram, two types of pictograms are used. Above each schematic image there are two small parallel arrows pointing upward. They symbolize the bright glow of the LED device. Before connecting the LED to 220V using a power supply, you must include a resistor in the circuit. If this condition is not met, this will lead to the fact that the working life of the LED will be significantly reduced or it will simply fail.

If you use a power supply when connecting, then only the voltage in the circuit will be stable. Considering the insignificant internal resistance of an LED device, turning it on without a current limiter will lead to the device burning out. That is why a corresponding resistor is introduced into the LED switching circuit. It should be noted that resistors come in different values, so they must be calculated correctly.

Helpful advice! The negative aspect of circuits for connecting an LED to a 220 Volt network using a resistor is the dissipation of high power when it is necessary to connect a load with increased current consumption. In this case, the resistor is replaced with a quenching capacitor.

How to calculate the resistance for an LED

When calculating the resistance for an LED, they are guided by the formula:

U = IxR,

where U is voltage, I is current, R is resistance (Ohm’s law). Let's say you need to connect an LED with the following parameters: 3V - voltage and 0.02A - current. So that when connecting an LED to 5 Volts on the power supply it does not fail, you need to remove the extra 2V (5-3 = 2V). To do this, you need to include a resistor with a certain resistance in the circuit, which is calculated using Ohm’s law:

R = U/I.

Thus, the ratio of 2V to 0.02A will be 100 Ohms, i.e. This is exactly the resistor needed.

It often happens that, given the parameters of the LEDs, the resistance of the resistor has a value that is non-standard for the device. Such current limiters cannot be found at points of sale, for example, 128 or 112.8 ohms. Then you should use resistors whose resistance is the closest value compared to the calculated value. In this case, the LEDs will not function at full capacity, but only at 90-97%, but this will be invisible to the eye and will have a positive effect on the life of the device.

There are many options for LED calculation calculators on the Internet. They take into account the main parameters: voltage drop, rated current, output voltage, number of devices in the circuit. By specifying the parameters of LED devices and current sources in the form field, you can find out the corresponding characteristics of resistors. To determine the resistance of color-coded current limiters, there are also online payments resistors for LEDs.

Schemes for parallel and serial connection of LEDs

When assembling structures from several LED devices, circuits for connecting LEDs to a 220 Volt network with a serial or parallel connection are used. At the same time, for correct connection, it should be taken into account that when LEDs are connected in series, the required voltage is the sum of the voltage drops of each device. While when LEDs are connected in parallel, the current strength is added up.

If the circuits use LED devices with different parameters, then for stable operation it is necessary to calculate the resistor for each LED separately. It should be noted that no two LEDs are exactly alike. Even devices of the same model have minor differences in parameters. This leads to the fact that when a large number of them are connected in a series or parallel circuit with one resistor, they can quickly degrade and fail.

Note! When using one resistor in a parallel or series circuit, you can only connect LED devices with identical characteristics.

The discrepancy in parameters when connecting several LEDs in parallel, say 4-5 pieces, will not affect the operation of the devices. But if you connect a lot of LEDs to such a circuit, it will be a bad decision. Even if LED sources have a slight variation in characteristics, this will cause some devices to emit bright light and burn out quickly, while others will glow dimly. Therefore, when connecting in parallel, you should always use a separate resistor for each device.

As for the series connection, there is economical consumption here, since the entire circuit consumes an amount of current equal to the consumption of one LED. In a parallel circuit, the consumption is the sum of the consumption of all LED sources included in the circuit.

How to connect LEDs to 12 Volts

In the design of some devices, resistors are provided at the manufacturing stage, which makes it possible to connect LEDs to 12 Volts or 5 Volts. However, such devices cannot always be found on sale. Therefore, in the circuit for connecting LEDs to 12 volts, a current limiter is provided. The first step is to find out the characteristics of the connected LEDs.

Such a parameter as the forward voltage drop for typical LED devices is about 2V. The rated current of these LEDs corresponds to 0.02A. If you need to connect such an LED to 12V, then the “extra” 10V (12 minus 2) must be extinguished with a limiting resistor. Using Ohm's law you can calculate the resistance for it. We get that 10/0.02 = 500 (Ohm). Thus, a resistor with a nominal value of 510 Ohms is required, which is the closest in the range of E24 electronic components.

In order for such a circuit to work stably, it is also necessary to calculate the power of the limiter. Using the formula based on which power is equal to the product of voltage and current, we calculate its value. We multiply a voltage of 10V by a current of 0.02A and get 0.2W. Thus, a resistor is required, the standard power rating of which is 0.25W.

If it is necessary to include two LED devices in the circuit, then it should be taken into account that the voltage dropped across them will already be 4V. Accordingly, the resistor will have to extinguish not 10V, but 8V. Consequently, further calculation of the resistance and power of the resistor is done based on this value. The location of the resistor in the circuit can be provided anywhere: on the anode side, cathode side, between the LEDs.

How to test an LED with a multimeter

One way to check the operating condition of LEDs is to test with a multimeter. This device can diagnose LEDs of any design. Before checking the LED with a tester, the device switch is set in the “testing” mode, and the probes are applied to the terminals. When the red probe is connected to the anode and the black probe to the cathode, the crystal should emit light. If the polarity is reversed, the device display should display “1”.

Helpful advice! Before testing the LED for functionality, it is recommended to dim the main lighting, since during testing the current is very low and the LED will emit light so weakly that in normal lighting it may not be noticeable.

Testing LED devices can be done without using probes. To do this, insert the anode into the holes located in the lower corner of the device into the hole with the symbol “E”, and the cathode into the hole with the indicator “C”. If the LED is in working condition, it should light up. This testing method is suitable for LEDs with sufficiently long contacts that have been cleared of solder. The position of the switch does not matter with this method of checking.

How to check LEDs with a multimeter without desoldering? To do this, you need to solder pieces of a regular paper clip to the tester probes. A textolite gasket, which is placed between the wires and then treated with electrical tape, is suitable as insulation. The output is a kind of adapter for connecting probes. The clips spring well and are securely fixed in the connectors. In this form, you can connect the probes to the LEDs without removing them from the circuit.

What can you make from LEDs with your own hands?

Many radio amateurs practice assembling various designs from LEDs with their own hands. Self-assembled products are not inferior in quality, and sometimes even surpass their manufactured counterparts. These can be color and music devices, flashing LED designs, do-it-yourself LED running lights and much more.

DIY current stabilizer assembly for LEDs

To prevent the LED's life from being exhausted ahead of schedule, it is necessary that the current flowing through it has a stable value. It is known that red, yellow and green LEDs can cope with increased current load. While blue-green and white LED sources, even with a slight overload, burn out in 2 hours. Thus, for normal operation LED, it is necessary to resolve the issue with its power supply.

If you assemble a chain of series- or parallel-connected LEDs, you can provide them with identical radiation if the current passing through them has the same strength. In addition, reverse current pulses can negatively affect the life of LED sources. To prevent this from happening, it is necessary to include a current stabilizer for the LEDs in the circuit.

Qualitative features LED lamps depend on the driver used - a device that converts voltage into a stabilized current with a specific value. Many radio amateurs assemble a 220V LED power supply circuit with their own hands based on the LM317 microcircuit. Elements for such electronic circuit have a low cost and such a stabilizer is easy to construct.

When using a current stabilizer on LM317 for LEDs, the current is adjusted within 1A. A rectifier based on LM317L stabilizes the current to 0.1A. The device circuit uses only one resistor. It is calculated using an online LED resistance calculator. Available devices are suitable for power supply: power supplies from a printer, laptop or other consumer electronics. It is not profitable to assemble more complex circuits yourself, since they are easier to purchase ready-made.

DIY LED DRLs

The use of daytime running lights (DRL) on cars significantly increases the visibility of the car during daylight hours by other road users. Many car enthusiasts practice self-assembly of DRLs using LEDs. One of the options is a DRL device of 5-7 LEDs with a power of 1W and 3W for each block. If you use less powerful LED sources, the luminous flux will not meet the standards for such lights.

Helpful advice! When making DRLs with your own hands, take into account the requirements of GOST: luminous flux 400-800 cd, luminous angle in the horizontal plane - 55 degrees, in the vertical plane - 25 degrees, area - 40 cm².

For the base, you can use a board made of aluminum profile with pads for mounting LEDs. The LEDs are fixed to the board using a thermally conductive adhesive. Optics are selected according to the type of LED sources. In this case, lenses with a luminous angle of 35 degrees are suitable. Lenses are installed on each LED separately. The wires are routed in any convenient direction.

Next, a housing is made for the DRLs, which also serves as a radiator. For this you can use a U-shaped profile. The finished LED module is placed inside the profile, secured with screws. All free space can be filled with transparent silicone-based sealant, leaving only the lenses on the surface. This coating will serve as a moisture barrier.

Connecting the DRL to the power supply requires the mandatory use of a resistor, the resistance of which is pre-calculated and tested. Connection methods may vary depending on the car model. Connection diagrams can be found on the Internet.

How to make LEDs blink

The most popular flashing LEDs, which can be purchased ready-made, are devices that are controlled by the potential level. The blinking of the crystal occurs due to a change in power supply at the terminals of the device. Thus, a two-color red-green LED device emits light depending on the direction of the current passing through it. The blinking effect in the RGB LED is achieved by connecting three separate control pins to a specific control system.

But you can make an ordinary single-color LED blink, having a minimum of electronic components in your arsenal. Before you make a flashing LED, you need to choose a working circuit that is simple and reliable. You can use a flashing LED circuit, which will be powered from a 12V source.

The circuit consists of a low-power transistor Q1 (silicon high-frequency KTZ 315 or its analogues are suitable), a resistor R1 820-1000 Ohms, a 16-volt capacitor C1 with a capacity of 470 μF and an LED source. When the circuit is turned on, the capacitor is charged to 9-10V, after which the transistor opens for a moment and transfers the accumulated energy to the LED, which begins to blink. This circuit can only be implemented when powered from a 12V source.

You can assemble a more advanced circuit that works in a similar way to a transistor multivibrator. The circuit includes transistors KTZ 102 (2 pcs.), resistors R1 and R4 of 300 Ohms each to limit the current, resistors R2 and R3 of 27000 Ohms each to set the base current of the transistors, 16-volt polar capacitors (2 pcs. with a capacity of 10 uF) and two LED sources. This scheme powered by source DC voltage 5V.

The circuit operates on the “Darlington pair” principle: capacitors C1 and C2 are alternately charged and discharged, which causes a particular transistor to open. When one transistor supplies energy to C1, one LED lights up. Next, C2 is smoothly charged, and the base current of VT1 is reduced, which leads to the closing of VT1 and the opening of VT2 and another LED lights up.

Helpful advice! If you use a supply voltage above 5V, you will need to use resistors with a different value to prevent failure of the LEDs.

DIY LED color music assembly

To implement fairly complex color music schemes on LEDs with your own hands, you must first understand how it works simplest scheme color music. It consists of one transistor, a resistor and an LED device. Such a circuit can be powered from a source rated from 6 to 12V. The operation of the circuit occurs due to cascade amplification with a common radiator (emitter).

The VT1 base receives a signal with varying amplitude and frequency. When signal fluctuations exceed a specified threshold, the transistor opens and the LED lights up. The disadvantage of this scheme is the dependence of blinking on the degree of the sound signal. Thus, the effect of color music will appear only at a certain level of sound volume. If you increase the sound. The LED will be on all the time, and when it decreases, it will flash slightly.

To achieve a full effect, they use a color music circuit using LEDs, dividing the sound range into three parts. The circuit with a three-channel audio converter is powered from a 9V source. A huge number of color music schemes can be found on the Internet at various amateur radio forums. These can be color music schemes using a single-color strip, an RGB LED strip, as well as a scheme for smoothly switching LEDs on and off. You can also find diagrams of running LED lights online.

DIY LED voltage indicator design

The voltage indicator circuit includes resistor R1 (variable resistance 10 kOhm), resistors R1, R2 (1 kOhm), two transistors VT1 KT315B, VT2 KT361B, three LEDs - HL1, HL2 (red), HLЗ (green). X1, X2 – 6-volt power supplies. In this circuit, it is recommended to use LED devices with a voltage of 1.5V.

The operating algorithm of a homemade LED voltage indicator is as follows: when voltage is applied, the central green LED source lights up. In the event of a voltage drop, the red LED located on the left turns on. An increase in voltage causes the red LED on the right to light up. With the resistor in the middle position, all transistors will be in the closed position, and voltage will only flow to the central green LED.

Transistor VT1 opens when the resistor slider is moved up, thereby increasing the voltage. In this case, the voltage supply to HL3 stops, and it is supplied to HL1. When the slider moves down (voltage decreases), transistor VT1 closes and VT2 opens, which will provide power to the LED HL2. With a slight delay, LED HL1 will go out, HL3 will flash once and HL2 will light up.

Such a circuit can be assembled using radio components from outdated equipment. Some assemble it on a textolite board, observing a 1:1 scale with the dimensions of the parts so that all elements can fit on the board.

The limitless potential of LED lighting makes it possible to independently design various lighting devices from LEDs with excellent characteristics and a fairly low cost.