/gao/wu/wuli80.html In the large family of electric light sources, the incandescent lamp was successfully invented by Edison on October 21, 1879. To this day, incandescent lamps are still benefiting mankind. However, Edison was not the first to study electric light sources. As early as the early 19th century, some people were studying the use of electricity for lighting. Among them, Faraday's teacher David invented the arc lamp. David discovered in a chemical experiment that when two charged carbon rods are close to a certain distance, they will emit extremely bright arc light. After the emergence of generators in the second half of the 19th century, arc lamps were widely used for lighting in squares, theaters, etc. However, arc lamps are too dazzling and consume too much electricity, making them unsuitable for home use. Therefore, research on the invention of electric light sources has continued. Many people have continued to carry out research and exploration, and accumulated a lot of experience and lessons. Among them, one of David's discoveries has important enlightening significance. David discovered that when an electric current passes through a platinum wire, it will heat up and glow, and will quickly burn in the air. This is a typical manifestation of the thermal effect of electric current, and it is also a glimmer of light that points the way for incandescent lamp research. In 1878, while researching the phonograph, Edison also began research on incandescent lamps. Although Edison was only 31 years old this year, he was already a seasoned inventor. His level is mainly reflected in the fact that he has mastered a set of scientific methods. When Edison studied incandescent lamps, he first started by gathering information. He collected various information about lighting, from oil lamps, candles, gas lamps to various electric lamps. He conducted detailed research on a large amount of information, including relevant excerpts and notes. More than 40,000 pages. After repeated demonstrations, Edison was convinced that incandescent lamps save electricity and are low in cost. As long as the problem of filament life is solved, the future is very bright. After the research topic was selected, the institute was busy. Edison organized and directed seven assistants with rich experience and superb skills to launch a fierce attack on the filament problem. They experimented with carbon strips, ruthenium wires, chrome wires, platinum wires, etc., but made no progress. The research continued into the second year, and they tried graphite, wood, straw, flax, horsehair and various metals... They used heuristic methods and experimented with all the materials they could find. They tested more than 1,600 materials, but still failed. Satisfactory results can be obtained at this time. Many people lost confidence in Edison's research. Edison's research institute is facing a severe test. When everyone was at a loss, Edison suddenly thought of "cotton thread". He immediately asked his assistant to find cotton thread, put it into the crucible and carbonize it. Carefully put the carbonized cotton thread into the bulb. The charcoal thread is thin and brittle. It was broken with a little force. The installation was not successful until the evening of the third day. Vacuuming technology has come a long way. Having been able to pump the air pressure in the light bulb to one millionth of an atmosphere, Edison decisively turned on the power switch. After 13 months of hard work. Finally, the dawn of victory came - the light bulb emitted a steady, soft light. The light bulb stayed lit for 45 hours before the filament burned out. Now the world's first incandescent lamp with practical value was finally invented and successfully trial-produced. This day was October 21, 1879. Edison in the experiment The initial victory did not satisfy Edison. In order to improve the life of the filament, they never stopped new exploration for a moment. Edison and his assistants successively tested more than 6,000 plant fibers collected from all over the world, and finally selected a filament made of Japanese bamboo silk. Two years of hard work paid off, and the lifespan of the Edison incandescent lamp has reached thousands of hours. By the spring of 1882, Edison Research Institute produced the first practical incandescent lamps. In the fall of that year, Edison built a power station and began to provide power to electric light users. In order to promote this invention and increase users, Edison announced that all users who install incandescent lamps can use it for free for three months. However, people always have a process of understanding new things, and incandescent lamps are no exception. Although many measures have been taken, There were still not many users, so Edison led his assistants to go door-to-door to solicit opinions. Users generally reported that it was inconvenient to use electric lights. It turned out that at that time, the power supply used AC series connection, and the electric gates were uniformly controlled by the power supply station - all the lights were turned on at the same time; Turn off the lights and darken every house at the same time. If one of the light bulbs is broken, the rest of the light bulbs will also be cut off at the same time, causing darkness.
For the convenience of users, Edison Research Institute changed the series power supply to parallel power supply, and each household installed independent light switches. They also developed a series of new generators, voltage regulators, junction boxes, fuses, etc. to ensure the safety of the lights. Running equipment, New Yorkers finally felt the benefits of electric lights. Within a few years, electric lights replaced gas lights. Incandescent lamps are also being continuously improved during the promotion and use. Especially after the use of tungsten filament, the life of the bulb has been greatly extended, even exceeding 10,000 hours, the incandescent lamp is the greatest invention of the 19th century and one of the brilliant contributions made by the inventor Edison to mankind. However, as a philosopher said: "Any successful invention also "They are all inventions that have not yet been completed." Due to the limitations of his level of understanding and material and technical foundation, Edison's incandescent lamp could not be perfect. Therefore, Edison never stopped researching and improving his incandescent lamp. Taking over the baton from Edison, research on electric light sources continued. Thomas Alva Edison (February 11, 1874 - October 18, 1931) was an American inventor and one of the greatest geniuses in the history of technology. Edison owned 1,093 invention patents such as incandescent lamps, phonographs, carbon microphones, and movie projectors. He also founded the world's first industrial research laboratory. Edison was born in Mylan, Ohio. He only attended elementary school for 3 months, and later learned lessons from his mother. He started to make a living by himself at the age of 12, working as a newsboy, telegraph operator, etc. Later, influenced by Faraday's works, he devoted his life to electrical experimental research and technological inventions. In 1868, the earliest "electric voting recording machine" was invented. In 1869, the "Quote Machine" was invented. In 1870, a laboratory and factory were established in Newark. In 1876, the invention of the carbon microphone made the telephone practical. In 1879, the incandescent light bulb was invented. In 1883, the "Edison Effect" was invented - the basis of the electron tube and the electronic industry. In 1887, Edison Research Institute was founded; the phonograph was invented. In this institute, the mimeograph machine, the fluoroscope, the dictation recorder, etc. were successively invented. In 1889, the movie projector and camera were invented. In 1891, the magnetic concentrator was invented. In 1895, the X-ray machine was invented. In 1909, the Edison battery (alkaline battery) was invented. In 1912, the sound film, which was a combination of a movie camera and a gramophone, was invented. In 1915, in the context of World War I, he served as chairman of the Naval Advisory Committee and guided the research of torpedoes and anti-submarine equipment. In 1912, rubber was successfully extracted from "Autumn Euphorbia". /oblog/user1/panxudong/archives/2006/2332.html