Many people wonder why a diode of the same power (for example 50W) costs 100 rubles in a Chinese online store, but 500 rubles in Russia. Chinese sellers and manufacturers wisely use the characteristics of LEDs, which cannot be measured without special equipment. In addition, they have learned to produce very cheap and low-quality ones. 99% of buyers do not understand them and encounter them for the first time. A large difference in price gives a good reason for deception; you can always sell junk at the price of a branded one, which they skillfully do.
- 1. Chip size
- 2. Current strength on the crystal
- 3. Parameters of ultra-bright LEDs from 10W
- 4. Specifications 5050, 2835, 5730, 5630, 3528
- 5. Characteristics of LEDs for flashlights
- 6. Main characteristics
- 7. Detailed description
Chip size
You've probably seen that sometimes the seller writes the crystal size in the specifications, indicating it in “mil”. This is how thousandths of an inch are designated; in millimeters it is 0.0254 mm. A typical crystal has dimensions of 30*30mil and 45*45mil. In millimeters 0.762*0.762mm and 1.143*1.143mm. It is not very easy to measure, but you can compare it by eye if you have a standard. I use a digital caliper, accurate to 0.01mm. For measurements, you need a tool with sharp ends; a regular micrometer is not suitable, since the crystal is recessed in the body.
Matching size and power:
- 1W - 45*45mil;
- 1W - 30*30mil;
- 0.75W - 24*40mil;
- 0.5W - 24*24mil.
On-chip current
On LED matrices ah power can be found out by the number of installed control valves. They are visible in the form of dots under the yellow phosphor. Color and RGB do not have phosphor, they are clearly visible.
On high-power LEDs, 1 KR has a power of 1W and a rated current of 300mA. At this current, normal long-term operation is ensured. If 50 KR are visible, then they will be equal to 50W.
Parameters of ultra-bright LEDs from 10W
Let's look at the features of high-power LED matrices white light. To reduce the cost, the Chinese decided to install smaller and worse crystals at 0.5W and 0.75W, for which the rated current is 150mA and 220mA. For them, 300mA will be too much, they will degrade and overheat. Good ones should have a length and width between 30*30mil and 45*45mil.
When making a choice in the store, use this information to calculate the real parameters of powerful matrices from 10W, 20W, 30W, 50W, 70W, 100W.
To visually determine the quality of a high-power LED, use geometric parameters. It is best if the chips under the phosphor are square. Rectangular ones are practically a guarantee of inflated performance.
Specifications 5050, 2835, 5730, 5630, 3528
The numbers in the marking indicate only the size of the SMD case. And this has nothing to do with its power. For example, for SMD5050 the dimensions will be 5.0mm by 5.0mm.
In large packages SMD5630, SMD 5730, European and American brands Samsung, LG, Philips produce 0.5W ice chips. The Chinese skillfully take advantage of this and put a weak 0.01W power supply into the standard 5630 and 5730 case, selling them as 0.5W. That's why Chinese corn lamps are studded with weak diodes.
Technical characteristics of Chinese
Characteristics of LEDs for flashlights
In addition to producing low-quality LEDs, the Chinese have learned to produce counterfeits of ultra-bright LEDs for flashlights, LED beams, and bicycle lights. They copy the appearance 95-99%, but the parameters still remain Chinese, 30-40% worse than the originals.
This explains the low cost of batteries LED lights on Cree Q5, Cree XML T6, Cree XHP50. The cheapest ones are 100% fake. I checked it myself, having bought 10 different flashlights on Kriya Q5 and T6. They all turned out to be fake CRIs made by LatticeBright.
The characteristics of bright LEDs for flashlights are described in detail at the following links:
Main characteristics
There are many options to reduce the cost and replace expensive materials with cheap ones. The most main feature, that such a replacement does not affect appearance, which is why such questions arise.
List of differences affecting the price:
- base material, copper or aluminum;
- the number of conductors going to the crystal;
- conductor material;
- LED mass;
- service life according to standard L70 or L80;
- maximum operating temperature;
- number of Lumens per 1 Watt;
- phosphor quality;
- color rendering index CRI;
- crystal size;
- crystal quality;
- spread technical characteristics;
- precision soldering and assembly.
Some parameters can only be determined after 5000 hours. works:
- CD degradation rate;
- effective service life;
- quality of yellow phosphor.
I believe that the effective service period according to the L80 and L70 standards plays a primary role in payback. For street LED lamps secondary parameters do not play a special role.
Detailed description
1. On cheap LEDs, the base is made of aluminum; its thermal conductivity is worse than that of copper. This significantly affects the mass. The rate of heat removal from the radiators decreases, and during operation their temperature becomes higher.
2. The crystal has a very small size; to supply power, it is connected by thin conductors to external contacts. It's best if there are 4 of them, the worst is 2 pieces.
3. In branded diodes, the conductors are made of thin gold threads; they can withstand current surges, especially in a car. Gold is replaced with copper or gilded copper. Probably many of you have seen daytime running lights or LED bulbs which are flashing. When heated, contact with K is lost, and when cooled it appears again.
4. Copper is much heavier than aluminum or other alloys based on it. Therefore, a good LED should be heavy. For low-power 1W, 3W, 5W the difference will be small. And starting from 10W to 100W, the difference in weight will be 2-3 times.
5. Standard L70 and L80 determine the number of hours that it will work before the luminous flux decreases to 70% and 80% of the original. The Chinese write a standard value of 30,000 hours for everyone. and 50,000h.
6. According to the characteristics, LEDs have a maximum operating temperature at 60°. Already 70° is critical for them; a large cooling system is required. Good ones will work for the required time of 50-70 thousand hours at 110°.
7. The worst ones give 50 lm/W, the good ones up to 130 lm/W, the best ones up to 200 lm/W. When buying from the Chinese, do not expect more than 100 lm/W.
8. All white ice chips without phosphor glow blue. To give it a warm white or neutral white color, yellow phosphor is applied. It comes in different varieties; inexpensive ones quickly burn out. This leads to a color shift towards blue and a change in the color rendering index. A CRI index below 80 is not suitable for residential premises.
9. Color rendition is responsible for the accuracy of the color reproduction of an object that we see under LED lighting. At low CRI<80 цвета будут сильно искажены, поэтому светодиодные светильники и лампы с CRI <80 используют в уличном освещении, в подсобных и нежилых помещениях.
10.The current strength that can be supplied to it depends on the size of the CD. Square LED COB matrices (assemblies, modules) consist of ordinary 1W and 3W crystals. For them the standard is 30mil, 45mil. For high power COB LEDs at 10W, 20W, 30W, 50W, 100W the sizes can be 24*24mil, 24*44mil, 44*44mil.
For low-power LEDs, they can be of different sizes, even 2-3 LEDs in one housing, connected in series or parallel.
11. The same applies to high-power RGB LEDs. In terms of size, 1W and 3W CDs can be the same. The bad ones are labeled as 1W, which are better labeled 3W.
12. Indirectly, quality can be determined by the spread of parameters of the used RCs. They are turned on to glow slightly. Some will shine much brighter than others, there is a wide range. The more evenly they shine, the better.
13. The quality of assembly and installation of the CD affects the service life. All elements are subjected to strong heating and cooling, materials expand and contract. If heat dissipation deteriorates, then the phosphor around it begins to turn black.
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 WA 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, the last way is to distinguish LEDs by crystal size. To be sure to do this, you should purchase a USB microscope. This is a budget option and quite high 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
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.
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 located inside LED lamps, for example 9-12V at 350mA in a 3-diode lamp.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.
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.
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.
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 you have the same. 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!
Characteristics LED 1W
Power dissipation, PD type: 1 W
Luminous flux: 120 lm
Voltage drop, VF (min-max): 3.6 V
Forward current, IF type: 350 mA
Viewing Angle: 120°
Read more in the datasheet. There is a whole range of colors available for sale - blue, white, red, yellow, green. In appearance they are the same. If we start the LED without a cooler, it will burn out in the first 5 seconds. We will use the cooler from the video card. The fan itself was intended to be installed on a 10-watt matrix, but while it is on the way, we will do tests on a 1-watt LED.
I had this cooler on my video card, I don’t know what kind you have, but I think it will work with any video cards - their power is greater than that of the LED element. Next, we glue double-sided tape on the back side (this is for if you need to remove the LED) and drop a drop of glue on top of it." Titanium" or " Moment". We securely fix the LED. Please note: if the LED is not glued tightly to the radiator, it may burn out!
One-watt LED - video of work
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, one such lighting device 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 ordinary batteries.
Main brands
Sometimes there are negative reviews about LEDs, which write about poor 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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