Who knows the change and development of lights?

The bold imagination of physics professor 1802, in the medical college of surgery in Petersburg, Russia, a physics professor named Petrov announced that he intended to "use electricity to get light". /kloc-At the beginning of the 9th century, when bonfires, Song and Ming Dynasties, animal and vegetable oils and gas were still the main lighting methods, and electricity was still a new thing, this decision was tantamount to a fable. However, Petrov's enthusiasm was not suppressed by the public's cynicism, because not long ago, American physicist Franklin got inspiration by flying a kite and drawing sparks: Can the sparks generated when the two ends of the battery are connected by wires become a lasting lamp for lighting? In order to achieve the expected results, Petrov made unremitting efforts. Although he had never seen "lasting light" before his death, Petrov discovered "electric arc"-"If two carbon rods are close to each other, there will be a very bright white light or white flame between them, which will make the carbon rods burn faster or slower and completely illuminate the dark room." This is the earliest statement about electric lighting. The discovery of electric arc marks a decisive step in the transformation from electricity to light.

From arc lamp to incandescent lamp

Almost at the same time, 1809, the famous British chemist David, who was immersed in electrochemical research, also discovered the arc. He made a big battery himself, used 2000 voltaic cells, and got a stronger and brighter arc.

Petrov's experimental device is similar to David's, and it is actually the prototype of a new type of lamp-carbon electrode arc lamp. At that time, this kind of lamp used carbon rods made of ordinary charcoal, which burned too fast and the dazzling arc seemed to be a flash in the pan.

About 30 years later, someone remembered and applied hard and dense coke instead of ordinary charcoal. Because the burning speed of coke is slower than that of charcoal, the time of arc light is much longer.

Later, French scientists and technicians installed a clock device on the arc device, which enabled it to automatically adjust the distance between two carbon rods. In this way, the first carbon arc lamp was officially born.

1876, Russian electrician Ya Bu Lochekov transformed the arc lamp. He canceled the complicated clock mechanism and the magnetic lamp adjusting device, and let two carbon rods stand side by side, separated by an insulating piece made of clay or gypsum. He also used a device that can constantly change the direction of current, so that two carbon rods alternately act as anode and cathode, so that the combustion speed of the two carbon rods is basically the same, and the distance between the two ends can remain unchanged. Because these two carbon rods stand side by side and glow like candles, people give it a nice name "electric candle". Electric candles emit beautiful reddish or lavender light, and each candle can last for about two hours.

In the late 1970s, electric candles were all the rage. The electric candles invested and manufactured by the French General Electric Association were once used as street lamps and lit one by one in the street. In Paris alone, thousands of electric candles have replaced the original 70,000 kerosene lamps on the street, making the bustling Paris a veritable city that never sleeps. Electric candles also lit up the streets of London, Britain and ancient Persia, shining on the Grand Theatre of Rome and the Royal Palace of Cambodia. ...

The advent of arc lamp has opened up a new era of electric lighting, which is of great significance in the history of human lighting. Because of its strong luminosity, high luminous efficiency and good color rendering, arc lamp has unparalleled advantages in printing, plate making, film projection and other fields, and still occupies a place today. The electric candle consumes a lot of electricity, has a short life and produces harmful gases, so it almost disappeared in the lighting field after the incandescent lamp appeared.

From 65438 to 0879, Edison made the first batch of practical carbon filament incandescent lamps in the world on the basis of previous research and practice. Edison used an improved carbonization method to spread a cotton thread with carbon powder, bend it into a horseshoe shape, put it in a clay crucible and heat it at high temperature to make a filament, then sealed it in a glass bulb, and carefully evacuated the air inside. In those two days, 10 and 2 1, this light bulb began to light up and lasted for 45 hours! Edison made a great contribution to the invention of incandescent lamp.

From immaturity to maturity

The brilliance of incandescent lamps is deeply rooted in people's hearts, and a large number of inventors are committed to the improvement of incandescent lamps. In fact, before the birth of carbon filament incandescent lamp, people tried to use all kinds of refractory metals as filament, and after the advent of incandescent lamp, people spared no effort to find the ideal filament. Finally, in the ninth year of the 20th century, American Coolidge discovered tungsten, a filament material with excellent performance. Tungsten has many remarkable characteristics, its melting point is higher than any other metal element, and it evaporates little when heated, so tungsten is the most suitable material for filament. Using tungsten filament as filament to make incandescent lamp is a milestone in the development history of lighting technology. The introduction of tungsten filament made incandescent lamp win a decisive victory in the competition with kerosene lamp, gas lamp and gasoline lamp. The application of tungsten wire has strongly promoted the development of electric lighting industry and opened up a new era of electric lighting technology.

The improvement of incandescent lamps is not complacent. 19 13, Langmuir filled the glass bulb with nitrogen for the first time, which was another major innovation of incandescent lamp after the filament was changed from carbon filament to tungsten filament. When the glass bulb is filled with nitrogen, a thin protective layer of stable gas is formed around the filament, which enables the filament to work at a higher temperature, effectively inhibits the evaporation of tungsten filament, and overcomes the performance defects of tungsten filament in the use process (until today, inflation is still an important process in the bulb manufacturing process).

Later, in order to improve the luminous efficiency of incandescent lamps and prolong the service life of bulbs, people once again made great efforts on the composition and structure of filaments. The inventor introduced a new element-rhenium. Rhenium has the advantages of high melting point, corrosion resistance, good mechanical properties and much higher resistivity than tungsten. After rhenium plating, the strength and resistance of tungsten wire are greatly enhanced, and the service life can be extended by 5 times! At the same time, people began to make the filament spiral. On the one hand, it can reduce the occupied space and improve the luminous efficiency, on the other hand, it can continue to reduce the evaporation of tungsten and prolong the service life, which can be described as killing two birds with one stone. 1936, people made a double helix filament, which raised the working temperature of inflatable incandescent lamps to over 2500, and even reached 3000 for photographic incandescent lamps: the first generation of incandescent lamps was mature.

Throughout the 20th century until the 20th century, incandescent lamps have been a beautiful landscape in the big family of lighting appliances. Although in today's life, there have been more excellent fluorescent lamps, fluorescent lamps and neon lights than incandescent lamps ... but in ordinary people's home life, ordinary incandescent lamps still play an irreplaceable role.

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