Light diodes are low-voltage electroluminescent devices that emit light when electrons pass through an elementary pn junction. Light emission occurs during injection through the pn junction of minority carriers. Diodes can be excited by constant, alternating and pulse voltage.
The diode lamp contains an anode and a cathode. The anode is designed to attract the electrons that the cathode emits; a positive voltage is always applied to the anode. When an electric current is applied to the lamp contacts, an electric field is formed between the anode and cathode; it helps the electrons emitted from the cathode (such electrons are called free electrons) move toward the anode. Currently, LED lamps are the most promising direction in the development of lighting technology and light sources. Diode lamps replace incandescent and halogen lamps, begin to create competition even with energy-saving ones.
A diode lamp has its advantages and disadvantages. Its main advantage is low power consumption. It is about ten times lower than that of an incandescent lamp, and about three times lower than that of a fluorescent one. A small consumption of electric current is due to the fact that the power of diode lamps is quite low.
The second advantage is a long service life - 100,000 hours, or 11 years of continuous operation. The following advantage: the diode lamp is practically harmless, it does not contain mercury and is easy to dispose of. Due to the fact that during operation, the diode lamps practically do not heat up, they are considered fireproof, so they can be used in places with poor ventilation, for example in suspended ceilings. The advantage of the devices is their high mechanical strength, they are not even afraid of falling from a height, and all this thanks to the materials from which they are made.
The disadvantages of LED lamps are more than advantages. The main disadvantage is the very high price. For example, household diode lamps with a power of 9-10 W will cost up to 2000 rubles, and office type (Armstrong ceiling) - from 5000 rubles. The second drawback: the declared 100,000 hours of continuous operation by manufacturers in practice show a much shorter life. This is because there is a degradation effect of the LED crystals. The manufacturer gives a guarantee for his products 3-5 years. Given that the diode lamp pays off after 5 years, you can lose your money. The next disadvantage is narrowly focused light and an unpleasant spectrum of luminescence.
LED lamps have found their application in the automotive industry. Since the 1990s, automakers began to use LEDs in car headlights, brake lights, direction indicators, in dimensions, in interior lighting and the instrument panel, etc. Diode lamps for a car have a different spectrum of light: from red to blue. Now many manufacturers produce high-quality LEDs for cars of different models, this opens up great opportunities for tuning the car.