LEDs (light-emitting diodes), also known by the more familiar English name LED (abbreviation for light-emitting diode), are the real unsung heroes in the world of electronics. They perform dozens of different functions and are now used in almost every electronic device. So, for example, they display symbols on illuminated panels, transmit information from a remote control to a signal receiver, illuminate houses, or inform you about the current status of an appliance. Collected together, green, red and blue LEDs can form an image on a huge TV screen or control traffic at a traffic light.
Shines, but does not heat
In principle, LEDs are just miniature light bulbs that fit perfectly into any electrical circuit. But at the same time, they do not have an incandescent filament, which is mandatory for conventional lamps, as a result of which they do not heat up much. The light emitted by LEDs is only due to the movement of electrons in the semiconductor, so they have the same lifespan as a conventional transistor.
When comparing he alth resourceLED and incandescent lamps, then LED has thousands of hours more. Tiny LEDs have replaced the tubes that illuminate high-definition LCD screens, making them much thinner.
Where did this strange light come from?
Without delving into the jungle of physical processes, let's see what makes the LED glow.
Light is a form of energy given off by an atom, consisting of many small packets of particles with energy and momentum called photons. They are produced when electrons move from a distant orbit to a closer one. The greater the distance traveled by the electron, the greater the energy of the photon emitted by it, which is characterized by a higher frequency. This frequency is precisely responsible for the wavelength of light, which determines the color of the radiation. For example, the atoms in a standard silicon diode are arranged in such a way that an electron is incident over a relatively short distance. As a result, the frequency of photons is so low that it is invisible to the human eye - it is in the infrared part of the light spectrum. Of course, this is not necessarily a bad thing: infrared LEDs are ideal for remote controls in particular.
Red-lit LEDs open up a section of light radiation visible to humans and are already able, for example, to highlight numbers in electronic watches. Depending on the materials used in the LED, they can be configured to glow in infrared,ultraviolet and all colors of the spectrum visible between them.
Two from the chest, identical from the face
Shortly after the development of the red LED, LEDs of other colors appeared. Almost immediately they began to be combined, placing them in a single shell. A two-color LED is a device with two leads, where two oppositely directed diodes of different color radiation are installed in parallel in one housing. In this case, the color will depend on the polarity of the voltage supplied to the device.
Red-green LEDs are widely used as an indicator of device readiness for operation (red on - off, green - on).
There is no perfection in the world, or A couple of shortcomings of an ideal light source
Obviously, LED technology is still imperfect. One disadvantage is their vulnerability to high temperatures. Too much current flow and the consequent overheating of the LED circuit causes permanent burn-in, often referred to as LED melting. In addition, LEDs based on advanced semiconductor materials were, until recently, too expensive to be used as natural lighting. But since the 2000s, with the launch of mass production, the price of LEDs has fallen several times and has become commensurate with the cost of conventional lamps, and given the long life, bright light, environmental friendliness and amazing energy efficiency, the use of LEDs has become a more economical lighting option forat home.
The Great and Terrible Red Lantern
Let's dwell in more detail on where the red LED is used. It can rightly be considered the "big brother" in the LED family, if only because it was the first LED operating in the visible radiation spectrum. Naturally, they began to use it for practical needs earlier than others and, first of all, to attract attention in the event of equipment malfunction. Agree, when instead of a uniform rumbling of the engine, a red LED blinks rhythmically, highlighting one or another icon on the panel of your favorite car or beloved washing machine, then at least this causes a feeling of mild anxiety. Yes, it is for warning about such emergencies that this type of indicator is most often used.
The Mystery of Red
Red color has the longest wavelength and is the least susceptible to scattering, respectively, it is visible from the farthest distance. Therefore, it is not surprising that a flashing red LED is widely used for emergency and alarm lights. Moreover, the level of electricity consumption of LEDs of this color is the smallest among all other LEDs in the visible spectrum, which ensures the maximum operating time of the used lighting device.
Red LED lights are usually used where there is a need for high intensity light, while not disturbing other people. For example, they are preferred in the theatre, cinema and for reading astronomical maps. Red light is notstrains the eyes, contributing to a better expansion of the pupils, and allows you to perfectly see reflective objects.
And LED-technologies have found worthy application for gardeners. Blue light stimulates the initial growth of the plant, and the use of red LEDs improves the flowering and fruit set process. Here, LEDs are beyond competition, because, emitting a huge amount of light, they do not overheat and do not dry the air, unlike other types of lamps that can harm future crops.
The further, the more "wonderful"
Replacing old incandescent bulbs with LEDs is just the tip of the iceberg, the LED story is just beginning. Thanks to new developments, LED solutions are reaching new horizons that were previously inaccessible to them. The most likely development direction is organic light-emitting diodes, or OLEDs.
The organic materials used to make these semiconductors are malleable, allowing flexible light sources and even displays to be built today. It seems that OLED technology will pave the way for the next generation of TVs and smartphones. After all, it is really convenient to remove your TV from the wall, roll it into a tube and take it with you, for example, to the country house.
It's hard to say where LED technology will go in the future, but one thing is clear - there will be no return to the Edison light bulb.
