How to choose the right LED for your device?

SMD, THT, ultra-thin LEDs, emitting extremely bright light, with the possibility of inverted mounting, transparent, translucent, there are countless options … How to quickly and easily find yourself in a wide range of LEDs available on the market. Here is some background information.

Regardless of whether the LED diode is used in professional work or as a hobby, below we present the basic criteria that should be followed when choosing an LED diode.

At first glance, the LED diode seems to be a fairly simple component, it is worth paying more attention to several parameters of this small device to make sure that it will serve us long and reliably.

What type of diode, what color, what brightness?

1. Diode type SMD or THT?

SMD diodes are definitely easier and more convenient to use, both due to the simple, automatic assembly and the possibility of reflow soldering. On the other hand, classic LEDs with THT wires are still very popular. A fairly simple and inexpensive solution is to place the signaling element eg on the front plate; thanks to this, there is no need to use additional optical fibers. It is worth considering the use of spacers for LEDs, which greatly simplify the installation and guarantee that the LEDs are securely attached.

2. LED color or exact wavelength?

The choice of color is usually an individual matter. Most likely associate green light with positive status and red light with error status. In general, colors are assigned to the appropriate status at the discretion of the device designer. The wavelength of the light emitted is the best indicator of the true color of the LED.

By the term “wavelength” is meant the following two parameters:

  • The peak value of the lambda coefficient – that is, the exact value at which the LED lights up as brightly as possible.
  • The dominant of the lambda coefficient – that is the actual value of the wavelength, therefore the light that is lit by the diode. It should be remembered that the brightness waveform depends on the lambda factor and is not symmetrical on both sides of the peak value.


Color markings often depend on the manufacturers. Nevertheless, with the basic names of colors such as green, red, yellow, orange etc., we find a wide range of wavelengths. When choosing an LED, consider the wavelength first of all, not just the general classification of the color categories.

Manufacturers do not have one unified method of classifying colors. Thus, often LEDs with a wavelength of around 600 nm are classified by some as orange LEDs and others as red LEDs. The same applies to the classification of green LEDs (green can often have a yellowish tinge). It is also worth remembering that “pure green” LEDs have appeared on the market, which emit light of a shorter wavelength, in the case of which the green color is “cleaner” or cooler (the color is similar to blue). In addition, it must be mentioned here that InterElcom stands for pure green and yellow green on the products it distributes.

3. The efficiency of the diode

The brightness parameter indicates the emission of light by the selected diode at a given intensity of the current. The unit for which the brightness is usually given is mcd (milikandele), and the luminous flux – lm (lumens). The brightness in mcd determines the brightness level of the LED when viewed at right angles. On the other hand, the luminous flux corresponds to the total light output emitted by the LED diode.

If we compare two LEDs equipped with the same chip and two different optical systems, then a diode with a narrower beam angle will have much higher brightness, because the luminous flux in the main radiation axis reaches a much higher value expressed in lumens. In practice, however, this is not always an advantage as such LEDs appear much darker when viewed from a non-straight angle.

4.Transparent or translucent housing?

THT LEDs are most often available in transparent, translucent and even colored or translucent colored housings. The advantage of the translucent housing is the LED chip, which remains invisible, thanks to which we get the impression that the entire surface of the LED is lit. In addition, this type of LED has a slightly wider beam angle. Also in the case of two-color LEDs, a translucent housing is definitely the better choice due to smoother color transitions. Of course, you also need to remember that the LED can also be transparent, transparent (transparent with a color), diffusive milky and diffusive (with a color).

On the other hand, it often seems that the LED with a transparent housing shines brighter. For applications exposed to direct sunlight, transparent LEDs are better suited because translucent housings when illuminated by the sun or other strong light source appear white, making it much more difficult to tell whether the LED is lit or not.

When choosing a diode, one should also take into account the lifetime of the diode, i.e. the brightness of the light it emits depending on the operating time, usually given in tens of thousands of hours. The aforementioned value indicates the time until the brightness of the LED in question drops to 50% of its original value under certain conditions. After this time, the LED will still work, but the brightness will be much lower.

The above article has outlined the most important criteria that will help you choose the right model from the wide range of LEDs available from InterElcom . At the same time, it should be remembered that we can meet many other criteria depending on specific applications.

The InterElcom assortment includes LED diodes in standard versions and a wide range of additional equipment, including housings, various types of connectors and accessories.

Select the appropriate LEDs from our range or send us an inquiry. If you need more information about LEDs , we are happy to answer your questions.



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