SDM LEDs. Main technical parameters and markings of SMD LEDs. Connection requirements

LED lighting is based on the ability of semiconductors to convert electrical current into light output. Based on their purpose, devices are divided into two groups: indication and lighting. The first type has low power and is used to indicate devices. The second type is installed in lighting fixtures. SMD LEDs are the most common type of lighting elements.

What are SMD LEDs

SMD LEDs

Semiconductor devices made using surface mount technology are called SMD LEDs. They differ from other devices in their design features. The electronic chip is assembled on a printed circuit board made of copper or aluminum. A crystal is used as a chip. The surface mount method simplifies the production and reduces the cost of LEDs.

SMD electronic components are characterized by the maximum proximity of the semiconductor to the substrate, which removes heat. To create white light, the crystal is coated with a layer of phosphor. Main features of the device:

• high brightness;
• a monochrome crystal emits one color - white, red, blue, yellow;
• consists of one or more crystals;
• modules are capable of creating lighting with a dispersion angle from 100 to 160°;
• SMD diodes operate on direct current.

All semiconductor devices are characterized by a high working life.

Manufacturer markings

LED markings

Standard LED markings, the decoding of which provides information about the linear dimensions of the device, are applied by all manufacturers. The digital designation shows the length and width of the LED chip in fractions of a millimeter. In some cases, in addition to the standard size of the case, other parameters are indicated - color and power. For example: SMD 2835 UWC 5 – matrix size 2.8×3.5 mm, color – white (Ultra White Color), power 0.5 W. For surface mount electronic components there is a special code smd 2l.

LED characteristics

Device parameters affect the possibility of using them in various fields. The main characteristics of the products include: voltage, power, luminous angle, color temperature, luminous flux.

Current consumption value

The average current on a crystal is 0.02 A. For chips with several crystals, the characteristic increases as a multiple of their number. Fluctuations in the parameter negatively affect the glow intensity and service life. Increasing the current increases the color temperature of the chip and changes the hue of the glow. To ensure stability of characteristics, current-limiting resistors are connected.

Light output, beam angle, power

The luminous flux of an LED matrix is ​​different from the light created by an incandescent lamp. It is directional, so it is brighter in the central part. Typically the dispersion angle is in the range of 100-120°. Lenses are used to change the parameter. Based on power, devices are divided into 3 groups:

• low power – up to 0.5 W;
• average – 0.5-3 W;
• large - from 3 W.

The characteristic is necessary when calculating the power supply. It is calculated by the formula - current multiplied by voltage.

The nominal voltage of diodes is low, it is 1.1-4 V. The value varies due to differences in colors and materials of electronic components. The white device has the highest voltage.

Color temperature

Types of illumination depending on the color temperature of light

Radiation intensity or color temperature is important for the comfortable perception of lighting by the human eye. There are several categories of white light:

• 2700-3500 – warm;
• 3500-5000 – neutral or daytime;
• above 5000 – cold.

Color temperature is indicated in Kelvin (K), it is indicated in the labeling.

Dimensions and their influence on the properties of LED sources

Difference in illumination and directionality of illumination angle

Depending on the type, the size of SMD LEDs varies. The brightness of the elements increases with the dimensions. The glow area can be round or rectangular. The higher the parameter, the brighter the lighting. The light flux also depends on the number of crystals. In different models there are from 1 to 4 pieces. The power of the device depends on the size of the crystal. The characteristic is indicated by the manufacturer in “mil”, 1 mil = 0.0254 mm. For example: chip size 45x45 mil - power 1 W, 24x24 mil - 0.5 W.

Color range

The color of the LED depends on the semiconductor material and dopants. Primary colors: red, blue, green and yellow. White color is obtained by applying a layer of phosphor to a blue-emitting crystal. Two-color devices are used for indication. Three-color colors are used in displays.

Description of the main SMD LEDs

The number of standard sizes of LED lighting sources is constantly increasing. Several types are most widespread.

SMD 2835

The 2.8 x 3.5 mm model demonstrates high light output efficiency. Its parameters:

• current – ​​60, 150, 300 mA;
• power – 0.2, 0.5, 1 W;
• light flux – 20-100 lm.

The case is made of heat-resistant polymer, designed to heat up to 240-260°. The emitting area is rectangular in shape, covered with phosphor.

SMD 5050

The LED matrix consists of three crystals placed in one housing. Its dimensions are 5.0×5.0 mm. The technical characteristics of the LED components are similar to those of the SMD 3528 diode:

• the total current is – 0.02×3= 0.06 A;
• power – 3×0.7=0.21 W;
• Luminous flux – 18-20 Lm.

The chip is capable of emitting all shades of white, blue, red, yellow, green or tri-color RGB. Used in flexible tapes, lamps. The lighting mode can be adjusted.

SMD 5630

A new class of surface-mount devices, its dimensions are 5.6×3.0 mm. SMD 5630 models have improved brightness characteristics:

• rated current – ​​0.1-0.15 A;
• luminous flux – 32-57 Lm;
• voltage – 3-3.6 V.

To prevent overheating of the crystal, the chip is mounted on an aluminum substrate. The device is used in street and industrial lighting.

SMD 5730

The geometric parameters of the case are 5.7×3.0 mm. The large device is one of the ultra-bright diodes. The semiconductor is made from new materials that increase power. Specifications:

• rated current – ​​0.15,0.18 A;
• power – 0.5-1 W;
• luminous flux – 45 lm.

The lighting angle is 120°. The device is resistant to vibration, moisture, and has a long service life.

SMD 3014

A diode in a 3.0x1.4 mm package is one of the new options. Medium power model with good heat dissipation. Parameters:

• voltage – 2.7-3.3 V;
• current – ​​up to 0.3 A;
• glow – 9-11 lm.

The devices provide all shades of white light.

SMD 3528

One of the most popular and inexpensive chips. The length of its sides is 3.5×2.8 mm. The working platform is round, a layer of phosphor is applied to it. Specifications:

• operating current – ​​0.2-0.25 A;
• voltage – 3-3.2 V;
• luminous flux – up to 7 lm.

The brightness of the model depends on temperature; increasing the parameter leads to accelerated degradation of the crystal. At 75-80° the device shines 25% weaker.

Application and connection requirements

The scope of application of LED devices includes household, commercial and street lighting. Depending on the size of the SMD LEDs are placed in lamps or strip lighting. Several chips placed on the board replace standard incandescent and energy-saving fluorescent lamps. Devices with a wide angle of illumination are used in floodlights. LED matrices have replaced lamps in flashlights, headlights, signs, traffic lights and signs.

What are SMD LEDs? Surface Mounted Device – radioelements that do not have additional mounting connections. They are attached directly to the surface of the circuit board.

This type of ultra-bright LED is widely used in lighting designs. Due to the absence of a housing, the installation density increases and the weight of the final structure is significantly reduced.

Explanation of LED markings

Consider the markings using the example of an SMD 3528 warm white light matrix.

LED-WW-SMD3528

• LED – light-emitting diode;
• WW – warm white – warm white;
• SMD – surface mount diode;
• 3528 – matrix dimensions.

Many manufacturers try to uniqueize their product with various tricks. This is how the 5636, 5736 series appear. Their characteristics are completely identical to the basic models, and the last number indicates only minor changes in the standard size.

Technical characteristics of SMD 3528 (datasheet)

SMD 3528 is a single-chip matrix with low current consumption and relatively low brightness. But precisely because of this, you can design any backlight without worrying about additional heat removal. This assembly is used in night lighting strips, in lighting systems for advertising lightboxes, and illuminated signs.

In the (RGB) version, three crystals are used in the matrix.

SMD 3528 Dimensions

You can download the original datasheet SMD 3528 from the link.

Technical characteristics of SMD 5050 (datasheet)

SMD 5050 – three-crystal matrix. The power of a 5050 LED is proportional to three 3528 matrices placed in one housing. 5050 is used in surface mount systems where increased backlight brightness is required with a limited light emitter area.

SMD 5050 Dimensions

You can download the original datasheet SMD 5050 from the link.

Technical characteristics of SMD 5630 and 5730 (datasheet)

Comparison tables of parameters

General table of technical characteristics 3528, 5050, 5630, 5730:

The type of LED is distinguished by crystal structure and color:

The exception is LEDs with three crystals on an LED matrix.

A three-chip SMD matrix, for example, in the 5050 series, has three anodes and three cathodes. It connects as three independent elements. For the RGB model 5050, the characteristics in the datasheet are written for each diode, since they have different power consumption parameters.

Such connection requirements are due to the fact that even absolutely identical crystals will have differences in the supply current and connecting without a current limiter will simply damage one of them.

REMEMBER!

1. It is not recommended to connect any LED models to a power source without a resistor. When using one resistor, only one type of LED can be connected in series.
2. In the case of using three-crystal diodes, each channel is connected through a separate resistor and connected to the same diode in the next module.
3. Do not connect LEDs with different load characteristics. In simple words, do not connect 3528 and 5050 together.
4. It is strictly contraindicated to use resistors with a resistance less than the nominal value. This will increase the load current of the LED and shorten its service life.

Super-bright LEDs, invented relatively recently, have already become a part of our lives. Compact and economical, they are successfully used both in portable lighting devices and in stationary lighting and illumination systems. Recently, powerful and compact SMD LEDs have become especially popular, which we will talk about today. After reading this article, you will find out why they are called that, how they differ from each other and where they can be found.

Features of SMD LEDs

The main visually noticeable difference between SMD LEDs and conventional ones is the design of their housing:

Conventional with axial leads (left) and SMD LEDs

If a regular diode has leads that are long enough to be mounted through holes in the board, then their SMD analogues have only small contact pads (planar leads) and are mounted directly on the board.

This assembly method is called surface mounting, hence the name of the LEDs: smd (English: Surface Mount Device). This installation is the simplest and can be entrusted to robots.

In addition, efficient heat removal from the crystal has become possible thanks to the very short but relatively massive pins and the fact that the device practically lies on the board. Indeed, despite their efficiency, super-bright diodes heat up during operation. This design feature made it possible to produce very miniature but powerful SMD LEDs that require good heat dissipation.

Today, the global industry produces many types of SMD LEDs, differing from each other in both dimensions and electrical parameters.

How to decipher the markings

Ultra-bright SMD LEDs are usually labeled with four numbers, and the line of devices produced today looks something like this:

There are, of course, many more types of devices, but these are enough for us to analyze the markings. How to understand this marking and what do the numbers mean? It turns out that there is nothing complicated here: the numbers indicate the horizontal dimensions of the SMD LED housing - length and width in hundredths of a millimeter. For example, the 5050 device has dimensions of 5.0x5.0 mm, and 3528 – 3.5x2.8 mm. The marking does not carry any further information. You can only find out the technical characteristics from the accompanying documentation or take the seller’s word for it.

Expert opinion

Alexey Bartosh

Specialist in repair and maintenance of electrical equipment and industrial electronics.

When buying LEDs, be sure to read the accompanying documentation - our “friends” from China have a habit of embedding crystals of various powers (usually lower) into a standard package. If the seller is silent about this, then you can easily get an LED with a power of, for example, 0.09 W instead of a one-watt one, but the markings and appearance will be the same!

Brief technical specifications

Although their digital markings do not carry any information about the characteristics of SMD LEDs, there is still some connection between the standard sizes and parameters of the devices. Let's consider the parameters of the most common types of light-emitting SMD semiconductors:

Main technical characteristics of SMD LEDs

* – depends on the color of the crystal glow

Now let's look at each of these types in more detail.

smd 3528

This type of smd LED can be single-chip (white, neutral, warm, blue, yellow, green, red) or three-chip (RGB). In the first case, the device has two terminals for connection, in the second - four: one common (cathodes) and three anodes. To protect them from the environment, the crystals are filled with a transparent compound or a compound with the addition of a phosphor that evens out the color characteristics of the diode.

As can be seen from the plate, this type of LED has a relatively low luminous flux. But thanks to its small size, moderate cost and ability to illuminate in different colors, including RGB, it has still found wide application in inexpensive lighting and decorative lighting devices.

Very often, 3528 LEDs are included in LCD backlight strips. This strip with SMD LEDs is most often used for decorative purposes.

smd 5050

Unlike the 3528, the 5050 is exclusively a three-chip or quad-chip (RGBW) design. If the device is single-color, then all three crystals have the same or close (to equalize the color characteristics) color of light emission. This means that the 5050 diode has three times the brightness of its single-chip brother smd 3528. As in the first case, the crystals are protected by a compound with or without a phosphor.

This is perhaps the most popular device used for decorative lighting and illumination. It has an optimal cost/power ratio and can provide any backlight color (if using rgb5050), including high-brightness white (four-crystal version), by simply changing the power on each of the crystals.

Most often, such LEDs are built into LED decorative strips such as:

• single-channel, where three crystals are connected in parallel and powered by the same voltage;
• RGB and RGBW, having three and four channels respectively.

Thanks to the sufficiently high power of the diodes, even at their density of 60 pcs. per 1 meter of LED strip it can be successfully used not only for decorative lighting, but also for interior lighting. At the same time, the user can change the color temperature and even the color of the lighting independently; to do this, it is enough to install the appropriate controller.

smd 5630 and 5730

The smd 5630 is a single-chip powerful device (see table above) capable of creating a luminous flux of up to 57 lumens. Thanks to the built-in protection assembled on two stabistors, the device is able to withstand pulse current up to 400 mA and polarity reversal. The LED has 4 pins, but only two are involved in the operation of the crystal. The remaining two and the metal substrate are used for better heat dissipation. The LED glow color is white with different color temperatures.

5730 devices can be either single or dual chip. The former have characteristics similar to the 5630, the latter are twice as powerful (1 W) and are able to create a luminous flux of up to 158 lm.

Both types of devices emit white light of different color temperatures and can be used to make powerful LED strips, lamps, and spotlights.

A single-chip compact device of moderate (0.12 W) power and a luminous flux of up to 11 lm. Depending on the version, it can emit white light of different color temperatures, as well as blue, yellow, green, red and orange. To protect from the environment and correct color temperature, the crystal is coated with a compound containing a phosphor.

The main area of ​​application of smd 3014: LED strips and modules for decorative lighting, spotlights and lamps for them. Often used to make car lamps.

smd 2835

High power single-chip LED. Available in three versions: 0.2, 0.5 and 1 W. It emits white light of different color temperatures, the body size is the same as the 3528 device, but differs from the latter in the rectangular lens (the 3528 has a round lens).

Due to the high popularity of devices, a lot of fakes are produced, in which crystals of lower power are installed. So, although the Chinese smd 2835 is officially produced, it is equipped with a crystal of only 0.09 W. Externally, it can be impossible to distinguish it from a one-watt one due to the phosphor added to the compound, since it is opaque, and accordingly, it will not be possible to estimate the dimensions of the crystal by eye.

LEDs are used in various fields of lighting technology.

The most common SMD LEDs are crystals mounted on the surface of the board.

This design allows you to get maximum power with minimal dimensions.

This technology has both advantages and disadvantages, which leading manufacturers are constantly working to eliminate.

This type of LED is a board on the surface of which a crystal grown using metal-organic epitaxy technology is fixed. The most important stage of production is the creation of contacts and their coating with metal films.

Each diode is mounted in a housing, equipped with leads, and coated with a compound that removes or emits light. White LEDs are coated with phosphor. A dome is installed on the crystal to focus the light. Heat is removed through the substrate; if the diode is powerful, a radiator is installed. Electrical current is converted into light in a pn junction (just like any other diode).

The main advantage of the SMD design is the maximum proximity of the crystal to the substrate, which removes heat. One or more LEDs are mounted on one board. If there are a large number of them in one lighting device, the light is powerful enough without installing additional optical systems. Ordinary glass is sufficient, the losses due to which do not exceed 8%.

SMD packages vary in shape and size and are directly connected to the circuit board using a pad.

Attention! Due to its simplicity, installation can be performed by a non-specialist.

How to decipher the markings

The marking indicates the type of LED (surface mounted - from the English “surface mounted device”), and indicates the standard dimensions of the diode housing in millimeters. For example, the length and width of the SMD 5050 board is 5x5 mm. Surface-mount technology is used in the production of lighting devices.

Brief technical specifications

When manufacturing lighting fixtures, manufacturers are guided by several characteristics:

• board dimensions;
• number of crystals;
• voltage and current;
• light flux;
• temperature of the operating environment.

Table of the most common SMD LEDs:

These bulbs can be single, double or multi-colored. From them you can create rigid and flexible modules of any shape (round, rectangular, linear, with a base). A round radiator is used in floodlights.

Reference! The number of diodes in the module is gradually decreasing due to the advent of high-voltage SMDs (15 and even 45 V).

Led SMD 3528 are rectangular, thanks to them Surface-mount technology is progressing. There are 2 contacts on the short sides, the minus is indicated by a cut. The surface covered with phosphor is round, the brightness of the radiation depends on the temperature - the higher it is, the lower the brightness (a quarter decreases when it reaches +80). The main area of ​​application is the production of tapes consisting of 30, 60 or 120 diodes per meter.

Read also Formula and example of calculating a limiting resistor for an LED

The 5050 has 3 of the same LEDs as the 3528, that is, the power is increased by 3 times. There are 6 anodes on the surface and 6 cathodes at the cut (2 from each crystal). This is a more advanced version of the 3528, allowing the production of colored LEDs (from red, green and blue crystals). Flowers can be controlled separately. Voltage 3.3 V, 30 or 60 diodes are installed per meter of tape.

SMD 5630 and 5730

SMD 5630 marked a new stage in technology development. Other materials are used in production to increase power and luminous flux; RGB products are available. 60 pieces are mounted in tapes per meter, 72 pieces in metal rulers.

SMD 5730 is structurally similar to 5630, the main differences are increased light flux and only 2 contacts. The modification with a current of 300 mA can operate in pulse mode, the crystal temperature can reach +130°C. To increase power, SMD 5630 and 5730 are installed on a metal board that effectively removes heat.

SMD 3014

SMD 3014 belong to the group of relatively new LEDs operating from 3-3.6 V. The minimum light output is for white crystals, the maximum is for colored ones. The anode and 2 cathodes are located on the bottom of the housing. Compact dimensions make installation easy. The tapes have 30-120 elements, less often – 240 per meter.

Led 2835 has a rectangular pad covered with phosphor, the brightness is 2-3 times higher than that of 3528. The body is thinner (when compared with 5050), the contact pads are larger. 30, 60 or 120 of these diodes are installed per meter of tape.

Reference! Led SMD 3528, 2835, 5050 and 5630 are one LED, differing in the number of crystals and the shape of the housing. It is these parameters that determine brightness and power. The 5050 and 5630 (5730) have a wider window for light output, providing increased efficiency per lm/W.

Application of SMD LEDs

SMD LEDs have recently begun to be used as general lighting elements (after reaching a radiation intensity of 120 lm/W). This made it possible to produce LED lamps that can replace fluorescent and filament lamps. Manufacturers make sure that when replacing, consumers do not need to change or rebuild the lighting system or buy other lamps and spotlights. It is easy to assemble any matrices from SMD Led and integrate them into standard housings of fluorescent and halogen lamps.

The variety of SMD LEDs is expanding every day. SMD LEDs 3528, 2835, 5050, 3014, 5630 and 5730 are just the main sizes that have already gained worldwide popularity. In parallel with them, planar LEDs of various sizes with unpredictable parameters are being stamped under the “Made in China” sign.

If the time-tested characteristics of SMD 3528 and SMD 5050 LEDs, for the most part, correspond to the declared parameters, then there are many questions about light-emitting diodes of the new form factor. The Chinese have famously learned to counterfeit everything that is in demand in the consumer market, including LED products. Considering that LED lamps and strips from famous European companies are also assembled in China, what quality is included in them?

To clarify and see the differences among the most commonly used surface-mount LED chips today, we suggest comparing their electrical, optical and structural parameters. But first, a few phrases about the scope of their application.

Scope of application

SMD LED is used wherever something needs to be illuminated, illuminated or simply decorated. They have become a basic element in general lighting bulbs, in indicator panels and LCD TVs, and in emergency lighting systems. The most popular product assembled using SMD LEDs is still the LED strip, as well as its modifications in the form of rulers and modules.

In the new variation, multi-color strips are constructed on groups that consist of four powerful LEDs of different colors “R+G+B+W”. In total, their light output is much greater than that of conventional SMD 5050 LEDs, and the presence of an independent white LED expands the light shades.

Brief technical specifications

Now we will consider each of the most popular standard sizes individually. Using numbers, we will try to give an objective assessment of each type and reveal its strengths and weaknesses.

The manufacturing company has the right to change the opto-electrical parameters of SMD LEDs, indicating this in the passport data. For example, SMD 5730 from Samsung and Sanan will have slightly different luminous output.

Planar light-emitting diodes of this type can easily be called pioneers, thanks to them surface-mount technology has reached its current heights and continues to progress. LED SMD 3528 has a rectangular shape with an aspect ratio of 3.5 by 2.8 mm and a height of 1.4 mm. On each of the opposite sides of a shorter length, two contacts are visible. A cut (key) is visible on the casing from the cathode side. The working surface has a round shape, coated with phosphor.

The voltage drop at a nominal current of 20 mA depends on the color of the radiation. For white LEDs it can be in the range of 2.8-3.4V, and the luminous flux is 7.0-7.5 lm. The brightness of SMD 3528 is highly dependent on temperature and at 80°C it decreases by 25%.

This type of LED can be called an improved version of SMD 3528. The design of SMD 5050 made it possible to implement multi-color LEDs based on blue, red and green crystals with the ability to control each color separately. Inside the 5.0 by 5.0 mm case there are three crystals with technical parameters identical to SMD 3528.

Accordingly, the manufacturer does not recommend exceeding the operating current value more than 60 mA. In this case, the forward voltage will be 3.3V, and the luminous flux will be 18 lm. The total power consumption of one SMD 5050 is 200 mW in the operating temperature range -40/+65°C.

With LEDs, lighting devices have stepped into a new stage of development. In a case measuring 5.6 by 3.0 mm, scientists created not only a new form factor, but also a semiconductor device with some design features, made using new materials. Unlike its predecessors, SMD 5630 is characterized by greater power and light output.

The luminous flux can reach 58 lm, measured at a forward current of 150 mA. Through proprietary SMD 5630 it is allowed to pass up to 200 mA DC and up to 400 mA pulsed current with a duty cycle of 25%. The magnitude of the forward voltage depends on the shade of white light and can range from 3.0 to 3.6V.

The SMD 5630 LED has 4 pins with a key near the first pin. Of these, only two terminals are used: 2 – cathode (-) and 4 – anode (+). Like many modern LED SMD chips, there is a substrate on the bottom that helps improve heat dissipation.

SMD 5730

Light-emitting diodes of this modification appeared almost simultaneously with the 5630 case and are their analogues. In turn, they are divided into two types: SMD 5730-05 and SMD 5730-1 with power consumption of 0.5 and 1.0 W, respectively. Both types are classified as highly efficient LEDs with a thermal resistance of only 4°C/W. Unlike SMD 5630, 5.7 by 3.0 mm LEDs are visually higher (by 0.5 mm) and, instead of four, have two contacts.

SMD 5730-05 can withstand currents up to 180 mA while dissipating 0.5 W of active power. It also works perfectly in pulse mode with a pulse amplitude of up to 400 mA, the duration of which is no more than 10% of the period. Operating at rated DC current, the SMD 5730-05 provides brightness up to 45 lm.

SMD 5730-1 can be operated at direct current up to 350 mA and pulsed current with a duty cycle of no more than 10% up to 800 mA. The typical voltage drop in the operating position is 3.2V with a power of up to 1.1 W. The crystal can withstand a p-n junction temperature of 130°C and functions normally in the range from -40 to +65°C. Compared to SMD 5050, it has lower thermal resistance and 6 times more luminous flux, which in the proprietary version reaches 110 lm.

SMD 3014

SMD 3014 is a relatively new standard size belonging to the class of low-current LEDs. The maximum forward crystal current should not exceed 30 mA. Forward voltage zone 3.0–3.6V. White LEDs in warm shades have a minimum luminous output (8 lm), while cold LEDs have a maximum luminous output (13 lm). The dimensions of SMD 3014 are 3.0x1.4x0.75 mm. The anode and cathode leads are not limited to soldering at the ends. They go to the bottom of the case, which must be taken into account during the manufacture of the printed circuit board. The increased size of the contact pads improves heat dissipation and LED mounting. The anode lead is 2 times longer than the cathode.

The developers of SMD 2835 provided it with the best qualities that its predecessors had. The standard size 28 by 35 mm follows the shape of SMD 3528. But the new SMD 2835 has a much larger effective radiation area, which has a rectangular shape covered with phosphor. The element height is no more than 0.8 mm. Despite such small dimensions, the declared luminous flux can reach 50 lm.

In terms of other electrical characteristics, SMD 2835 is very similar to SMD 5730-05. In turn, the design of the element is identical to the SMD 3014 LED, when the anode and cathode terminals serve as a heat-sinking substrate.

Peculiarities

As we explore new Chinese SMD LED formats, this section can be expanded endlessly. For now, the most questions are about power consumption. By purchasing, for example, several SMD 5730 to assemble a lamp with your own hands or a ruler based on SMD 3014, the user expects to receive the luminous flux given in the data sheet. However, often a simple measurement of the load current and simple calculations show that the real power of one LED is 3–4 times lower. Why is this so?

Because the size of 5.7 by 3.0 mm does not mean that the corresponding crystal is mounted inside. In this skillful way, the Chinese mislead buyers. The most interesting thing is that the buyer has practically no choice. Finding a branded product with the right parameters is difficult.

When designing a power supply with your own hands, you need to strive to ensure that the actual current in the load is approximately 95% of that specified in the technical specifications. By slightly underloading the LED, you can achieve an increase in operating life even in the case of low-quality Chinese LEDs.

For all LED models, luminous flux values ​​are indicated for a color temperature of 5000–5500°K. Warmer tones will have 10% less light output, and cooler tones will have 10% more light output. In addition, it is worth remembering the error during testing, which can reach 7%. So don’t be surprised if instead of the stated 50 lumens, the chip produces no more than 43 lumens.

Before turning it on for the first time, always check the LED with a multimeter, since the pinout, in the case of a fake, may not match. Near the key there can be both the anode and the cathode of the chip.

In cheap monochromatic SMD 5050 LED strips you can see how all three chips of one LED are connected in parallel and powered by one resistor. This approach simplifies the layout of current-carrying tracks of a flexible printed circuit board, reduces the number of resistors used, and therefore reduces production costs. Of course, the service life of such a tape is also reduced.

Chinese craftsmen have learned to create SMD LEDs of any arbitrary shape, which can be easily verified. It is enough to remove the protective lens from several light bulbs from different companies (base E14, E27) and read the type of LED installed on the board. There seems to be no limit to the variety. It is impossible to predict the technical characteristics of such chips.

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