Today LEDs have a wide range of applications: backlighting, indication, holiday and household lighting. In order to choose LEDs, a complex of factors and characteristics must be considered.
Main characteristics and selection criteria for LEDs
The main characteristics of LEDs are voltage, lifespan, brightness, color, color temperature, luminous efficiency.
When choosing LEDs, you first need to determine the required power indicators and color parameters, which depend on the intended area of their use. Today, the following division of LEDs has developed depending on the power:
- low power LEDs (operating current 20mA per LED);
- high current LEDs (operating current from 50mA to 150mA);
- high power LEDs (from 150mA to> 1000mA).
The power of LEDs determines their applications. The first group is used in display systems, the second - for backlighting in cars, the third - in lighting systems.
The higher the LED power, the higher its temperature, and the faster aging occurs and the shorter the service life of the devices.
According to their color characteristics, they are distinguished: blue, green and ultraviolet high-brightness LEDs; red and infrared LEDs; yellow, green, orange and red LEDs. The most popular LEDs are green and red, which are used in display systems - information boards, aircraft dashboards and other information visualization systems. White LEDs are used for lighting. There are no such devices in their pure form, almost all white LEDs are three-component LEDs, consisting of three semiconductor emitters of red, green and blue light.
When choosing an LED, you should pay attention to the expected service life of the device. As of today, there is no standard that defines the lifespan of LEDs. The life span depends on how much current is passed through the LED during its life.
The higher the LED power, the higher its temperature, and the faster aging occurs and the shorter the service life of the devices.
It is worth choosing LEDs from trusted large manufacturers, such devices will last longer.
The brightness parameter is less important when selected, because the brightness of the LED can be controlled and changed up or down. Depending on the brightness, LEDs are divided into three main groups: LEDs of standard brightness (tens of millicandel); high brightness LEDs (hundreds of millicandel); ultra-high brightness LEDs (tens of candelas).
When choosing LEDs for lighting systems, it is worth considering the color temperature and luminous efficacy of the LEDs. Warm and cold colors are distinguished by color temperature. The light becomes warmer as the color temperature decreases, and colder as the color temperature rises. The color temperature of the sun is considered normal, i.e. 5500 degrees Kelvin, it is also considered the most comfortable for the eyes. White LEDs can have a color temperature ranging from 2,700 to 10,000 degrees.
The luminous efficiency of modern LEDs is an order of magnitude superior to traditional lighting sources.
In laboratory conditions, the luminous efficiency of LEDs of 100–150 lm / W has already been obtained. For comparison, for incandescent and fluorescent lamps it is equal to 15 and 80 lm / W.
According to this parameter, they are second only to fluorescent lamps, but LED production technologies are constantly being improved.
How much do LEDs cost
The cost of LEDs varies depending on power, color and other parameters. The price of devices with a power of 1 W or more starts at $ 0.9, and more than 10 W starts at $ 10. White LEDs are always more expensive than colored ones.
To estimate the cost of lighting LEDs, a price value of 1 lm (illuminance units) is used. This allows the cost of LEDs to be compared with the cost of other lighting systems. The average cost of 1lm of LED lighting today is about 2.5 rubles. For comparison - for incandescent lamps it is 0.01 rubles, CFL - 0.02 rubles / lm. At the same time, the cost of LEDs is reduced by about 4-5% per year.
