Due to my "crazy" passion, I am often asked how to choose the right LEDs? What characteristics should you pay attention to? In order to remove these questions, I had to sit down and write one, but detailed article, in which I would have to combine the two, since they are not separable. Get ready to strain your eyes and figure out the questions: how to choose LEDs and what characteristics of ice to pay close attention to.
1 Color temperature: Three shades of white - warm, neutral and cool. Choose neutral. And there is more light and more pleasant to the eye. This is a purely personal opinion.
2 LED power - the more the better. But for high powers, a large radiator is needed. For an analogue of a 100 W lamp, you need 12 to 14 W of diode light. Power diodes only from drivers. Do not increase the current to the diodes unnecessarily. The maximum efficiency will be only from the working value.
3 Luminous flux. Choose by this parameter corrected for crystal heating and unreliable manufacturer information.
4 Angle of dispersion. By this parameter, you can determine how the light will fall on the illuminated surface.
5 And most importantly, don't buy cheap diodes. Just make it a rule! There will be less frustrations with low light, poor lighting and rapid degradation.
Before buying chips, you should clearly understand what you are counting on. What result do you want to get. If you have an irresistible desire to change the lighting in living rooms, then you should pay attention to super-bright LEDs. If you want to light up an aquarium or a corridor, it is enough to purchase low-power diodes. It all depends on the number of LEDs that will be used.)))))) I read about "light up an aquarium or a corridor"))) I came up with a strange combination)))) Well, okay, I had fun though.
In the table, I summarized the data by type, with the desired place of application.
Filament LEDs and indicator lights do not make sense to consider, because I have not yet seen filament segments on sale separately, and indicator type 3 mm, etc. they are of no interest to me at all, and where they can be used, I can no longer imagine. The world of LEDs is so vast that I gave up on them.
Before going to the store, study the literature, datasheet on various types. The main characteristics to look out for are color, power, operating current and light data.
All diodes are classified according to the wavelength of the light emitted. The wavelength (and therefore the color) depends on the materials used during the production of LEDs. For 2015, we can firmly say that we can get the absolute majority of colors, not counting infrared radiation and ultraviolet. But we are still interested in diodes with a white glow. Are we going to make devices for lighting something? I will write a more detailed description of color temperatures and obtaining color diodes later.
Without going into the jungle, I will describe how they get white. So let's say for "dummies"). In no way did I want to offend anyone).
The first method - white is obtained by applying a yellow phosphor to blue LEDs (sometimes ultraviolet). Due to the phosphor, a "miraculous transformation" of blue into white occurs. In this case, the initial power of the chips decreases.
The second is getting white by mixing red, green and blue colors. In our case, when using the RGB method for white, the radiation of red, blue and green LEDs is used. 
White LEDs are divided into shades: warm, neutral and cold. Each of them has its own color temperature: warm - 2600-3700 K, neutral 3700-5000 K, 5000-10000 K. Below I will give a graphic picture, which clearly shows which color corresponds to a particular temperature.
Based on this characteristic, when choosing LEDs, we can get a first idea of HOW our diode will shine. In the photo, you can see with your own eyes what color each of the shades emits.
I would like to immediately warn those who love (are accustomed) to the color of incandescent lamps. Using warm shades of white (I remembered a movie about 50 shades of gray))), you should be prepared for the fact that the efficiency of the diode will proportionally decrease with increasing heat. In Russian, the yellower the color, the lower the efficiency at the same LED powers. Those. if you take 3 LEDs of the same power but three shades, then the greatest amount of light will be from the cold one, and then, in descending order, neutral and warm white.
This statement is true. I have conducted more than one experiment, collected more than one light source. And with the same characteristics of LEDs, chips with colder shades are much more efficient. And in spite of the fact that it is unofficially customary to install lamps with warm light in the premises, and on the streets of colder color I "stuck my whole house with pure white" light sources. More efficiency and no discomfort. Therefore, ahead of the question: what kind of lamp glow would you recommend to the apartment? I will answer. My, purely personal opinion - only neutral whites.
Power is one of the main characteristics of an LED
To date, the power of LEDs is overwhelming. From a few milliwatts to hundreds of watts. In our case, diodes with a power of 1, 3, 5 W will be the most optimal for general lighting. In some cases, it is not bad to use a 10 W matrix. In the garage, I made the lighting exactly 10 watts. Not a lot of them were needed and there was enough light for repairs.
We will focus on 1, 3 W diodes, because it is these types that are most common in lamps and luminaires. And they are easy to install at home. Despite the fact that many manufacturers use SMD diodes 5050, 3528, etc. soldering them is quite difficult and "unpleasant", so I will omit the story about them. But the principle remains the same - we CHOOSE diodes by power. The more power, the brighter we get the light.
But things are not so smooth. More power gives great heat. And in this case, it is worthwhile to clearly understand that for a long life of the diode, a good heat sink, a radiator is needed. 5W LED in a single copy does not require much cooling. But if you decide to assemble a lamp in 5-10 pieces, then the radiator will be weighty. And it's not even worth talking about aesthetics.
But back to our "rams" ... 1W LEDs produce a rated current of 350 mA, and 3 W at 700 mA. Ready-made drivers are already being released for them. It is necessary to power the LEDs only from the drivers. They keep the set current value at all times. And since diodes are very sensitive to amperes, it is important to supply them with direct current, which we can achieve precisely with drivers, and not with power supplies from mobile phones, computers, etc.
The number of diodes should be chosen on the basis that an analogue of a 100 W incandescent lamp is from 12 to 14 W of diode light. In this case, we need 12 one-watt and a driver for these 350 mA diodes. I do not want to go into the calculations of how to select drivers. Anyone interested, ask a question, I will calculate. Well, or someday I will write a separate opus).
I will say one more thing: the division by watts is conditional. In all characteristics of LEDs, there are two values - operating and maximum current. Let's say in one-watt units it is 350 and 700 mA. It would seem, "now I will give this diode to full and it will light up!" But no. According to the dependence of illumination on current, all LEDs show one diagram - the more current from the worker, the more the luminous intensity drops. Therefore, I never "overclock" my crystals. And I feed them only on what they are designed for.
Luminous flux is another important characteristic of LEDs
This characteristic is measured in lumens. Paying attention to it, we can get a more or less truthful understanding of how much light we will receive from the source. This is a rather "blurry" characteristic, since luminous flux depends on many factors. And if the description for the LED indicates that it produces 100 lumens, then this is not a fact. The correct determination of the true value lies not in production data, but in experimental data. Let's see one of the techniques.
Let's take three LEDs of the same power and luminous flux (according to the datasheet) at 350 mA - 120 lumens. When the diodes were powered from the 350 mA driver for 1 minute, without exceeding the crystal temperature, the following data were obtained. Moreover, LED # 3 produces 120 lumens at a current of only 300 mA. Those. we conclude that the data on the passport is not always correct. Choose diodes with the condition that the true lumens are 10-15 percent less. Then, in the end, you will not be disappointed, and in the case of a 3 diode, you will also be glad.
Another unpleasant news. With an increase in the temperature of the crystal, the luminous flux decreases. This characteristic is ALWAYS indicated in the data, in the form of a graph. Don't be lazy and watch. Typically, when the crystal is operating at 85 degrees, the luminous flux of most LEDs is reduced by 12 percent.
Scattering angle
Well, the last thing worth paying attention to is the scattering angle. Most diodes come with a 120 degree scattering angle. But this is not the final figure. The spread of angles starts from 15 and ends with 360 degrees (for example, filaments). Here you should decide again what you want to get. Spot light or diffused light throughout the room. 120 degrees is fine for a room, but it is better to use lenses to increase the angle. For a narrow beam, diodes with a dispersion of 40 degrees are more than enough.
There are several more characteristics of LEDs. But they are more interesting for industrial production. And for us, ordinary people, these are more than enough.
I can understand that for someone this information is difficult to understand, but this is only the first time. If you figure it out once, then in the future it will not be difficult to choose the right LED for your needs. In any case, I no longer "get sick" with the pangs of selection.
In contact with
