The common incandescent light bulb, which is used in almost every home, is often referred to as the Edison light bulb. The history of its invention was not so simple. Before giving artificial light to billions of people, it has come a long way of development.
Edison light bulb
American Thomas Alva Edison is one of the most enterprising people in this world. He owns about 4 thousand patents for various inventions. This man became the author of the phonograph, telegraph, carbon microphone, kinetoscope, iron-nickel battery and other devices. It is with his name that the idea of creating an incandescent light bulb is associated.
However, Edison's light bulb with a carbon filament inside was far from the first in the world. More than ten inventors worked on the problem of creating lamps of various shapes and sizes, inside of which bamboo, platinum and carbon filaments were located. Many of them were officially registered.
Why, among so many inventors, only Edison gained world fame? His main role was not in the idea of creating a lamp, but in developing a way to make the mechanism easy to use, cheap and accessible to everyone.
First attempts
It is difficult to say exactly who came up with the idea to create a light bulb. But before Edison's light bulb appeared, hundreds of experiments were carried out and many similar inventions were announced. Arc bulbs appear first, and then incandescent bulbs. In the 19th century, the discovery of the phenomenon led inventors to the idea of creating artificial light. This required connecting two connected wires to electricity and then moving them slightly apart. This is how a glow appeared between the wires.
There is information that the Belgian Gerard was the first to create a lamp with a carbon rod. Current was applied to the device and the rod produced light. Later it became known about the Englishman Delarue, who replaced coal with a platinum thread.
Such light bulbs were considered valuable discoveries, but their application was accompanied by great difficulties. Platinum filament was an expensive pleasure; not everyone could afford to use such a lamp. The carbon rod was much cheaper, but it was not enough for a long time.
Solid progress
In 1854, the German watchmaker Heinrich Goebel created a lamp with a thin carbon rod that shines much longer than the previous ones. The inventor managed to achieve this by creating a vacuum. Goebel's lamp went unnoticed for a long time, and only years later it was declared the first light bulb suitable for practical use (declaring Edison's patent invalid).
Joseph Swan and Alexander Lodygin worked on improving the mechanism. The latter patents the invention of a “filament lamp” operating on a carbon rod in a vacuum. In 1875, he distinguished himself noticeably by inventing “electric candles.” The Russian engineer used a kaolin filament that did not require a vacuum. Yablochkov lamps were used for street lighting and became widespread in Europe.
Mechanism improvement
The main direction has long been known. A rod of a certain material is placed in a vacuum and connected to an electric current. All that remained was to choose the right material for the electrode for a long-lasting glow.
In 1878, Edison became interested in finding a successful solution for light bulbs. The inventor acted using the method of practical trials: he carbonized a mass of plants and substituted various materials as a filament. After 6 thousand experiments, he manages to make a lamp from bamboo coals that lasts 40 hours. Edison's light bulb begins to be mass produced, displacing other lamps on the market. In 1890, engineer Lodygin registered the use of a tungsten rod, and later sold the patent to General Electric.
Edison's merits
While developing the lamp, Edison understood that in addition to the choice of materials, the design of the mechanism was also important. So, he invents a screw base, creates fuses, meters, the first switches, and electric generators. Many of the lighting components that Edison invented are standard and are still used throughout the world.
The inventor made light bulbs available to everyone. To do this, he began selling them at a reduced price. Edison cost a little more than a dollar. The enterprising American’s plans were to make the invention so affordable that even wax candles would seem like a luxury in comparison. Rapid automation of production made it possible to reduce costs while still producing large quantities of goods. Soon the cost of the lamp became about 22 cents. The inventor's dream came true - light bulbs appeared in every home.
Edison light bulbs in the interior
Nowadays, light bulbs are commonplace. They are affordable and very convenient to use. Moreover, many different types and models of lamps have appeared. Their practical importance has faded into the background; now they have become an important addition to the home interior.
“Edison's light bulb” (see photo above) is the name of a certain one. They are decorated in a retro style and are similar to those used in the time of Thomas Edison. Such lamps emit a soft, pleasant light and look like a glass bulb or ball on a durable cord. Edison light bulbs are often used to design public spaces - bars, cafes, or to decorate living rooms and bedrooms.
The electric incandescent lamp has long become an object without which it is difficult to imagine our lives. In the evening, when entering a house or apartment, the first thing we do is flip the switch in the hallway and within a moment a bright light flashes, dispelling the darkness around us. And at the same time, we don’t think about where such an ordinary light bulb came to us from and who invented the light bulb. The electric lamp has long become commonplace for us, but once upon a time it was akin to a real miracle.
Before the invention of electricity, people lived in twilight. With the onset of darkness, the dwellings were plunged into darkness and their inhabitants, in order to somehow disperse the darkness that frightened them, lit a fire.
To illuminate houses in different countries, lamps of various designs, torches, candles, and torches were used, and fires were lit in the open air, for example, on the road or in military camps. People treasured these light sources; they invented legends and composed songs about them.
However, the inquisitive human mind already in ancient times was looking for an alternative to all these devices. After all, they all gave little light, smoked heavily, filling the room with smoke, and besides, they could go out at any minute. Archaeologists who discovered amazing paintings inside the ancient Egyptian pyramids could not help but wonder how the ancient artists made these drawings despite the fact that natural light did not penetrate into the pyramids, and no soot was found on the walls and ceiling from torches or lamps. It is likely that the answer to this question has already been found in the city of Dendera, in the temple of the goddess Hathor. It is there that there are bas-reliefs, which may depict an ancient electric lamp similar to a gas-discharge lamp.
In the 9th century AD. In the Middle East, an oil lamp was invented, which became the prototype of a kerosene lamp, but it did not become widespread and remained a rare curiosity.
Thus, until the middle of the 19th century, the most popular light sources remained oil and fat lamps, candles, lanterns and torches, and in camp conditions - the same fires as in ancient times.
The kerosene lamp, invented in the middle of the 19th century, supplanted all other sources of artificial lighting, although not for long: until the electric light bulb appeared - the most common for us, but absolutely amazing for the people of that time.
At the dawn of discovery
The operation of the first incandescent lamps was based on the principle that conductors glow when electric current is passed through them. This very property of such materials was known long before the invention of the light bulb. The problem was that for a very long time the inventors could not find a suitable material for an incandescent filament that would provide long-lasting and effective, and also inexpensive lighting.
Background to the appearance of incandescent lamps:
Who first invented the light bulb
In the 1870s, serious work began on the invention of the electric light bulb. Many prominent scientists and inventors devoted years and decades of their lives to working on this project. Lodygin, Yablochkov and Edison - these three inventors worked in parallel on the design of incandescent lamps, so disputes still continue about which of them can be considered the world's first inventor of the incandescent electric lamp.
Lamp by A. N. Lodygin
He began his experiments on the invention of the incandescent lamp in 1870 after his retirement. At the same time, the inventor was simultaneously working on several projects: creating an electric plane, a diving apparatus and a light bulb.
In 1871-1874, he conducted experiments to find the most suitable material for an incandescent coil. Having initially tried to use iron wire and failed, the inventor began experimenting with a carbon rod placed in a glass container.
In 1874, Lodygin received a patent for the incandescent lamp he invented, not only Russian, but also international, patenting his invention in many European countries and even in India and Australia.
In 1884, for political reasons, the inventor left Russia. For the next 23 years he worked alternately in France and in the USA. Even in exile, he continued to develop new designs for incandescent lamps, patenting those that used refractory metals as the material for the spiral. In 1906, Lodygin sold these patents to the General Electric Company in the USA. During his research, the inventor came to the conclusion that the best materials for incandescent filaments are tungsten and molybdenum. And the first incandescent lamps produced in the USA were made according to his design and with tungsten filament.
Yablochkov's lamp P.N.
In 1875, finding himself in Paris, he began inventing an arc lamp without a regulator. Yablochkov had begun work on this project even earlier, while living in Moscow, but failed. The capital of France became the city where he was able to achieve outstanding results.
By the beginning of the spring of 1876, the inventor completed work on the design of an electric candle, and on March 23 of the same year he received a patent for it in France. This day became significant not only in the fate of P. N. Yablochkov himself, but also a turning point for the further development of electrical and lighting engineering.
Yablochkov's candle was simpler and cheaper to operate than Lodygin's coal lamp. In addition, it did not have any springs or any mechanisms. It looked like two rods clamped in two separate terminals of a candlestick, which were separated by a kaolin partition, isolating them from each other. An arc charge was ignited at the upper ends, after which the arc flame slowly burned the coal and vaporized the insulating material, at the same time emitting a bright glow.
Later, Yablochkov tried to change the color of the lighting, for which he added salts of various metals to the insulating material for the partition.
In April 1876, the inventor demonstrated his candle at an electrical exhibition in London. The large audience was delighted with the bright bluish-white electric light that flooded the room.
The success was incredible. The scientist and his invention were written about in the foreign press. And already at the end of the 1870s, streets, shops, theaters, hippodromes, palaces and mansions were illuminated with electric candles not only in Europe, but also in the USA, Brazil, Mexico, India, Burma and Cambodia. And in Russia, the first test of Yablochkov’s electric candles took place in the fall of 1878.
It was a real triumph for the Russian inventor. After all, before his candle, there was not a single invention in the field of electrical engineering that would so quickly become popular throughout the world.
Edison lamp T.A.
He conducted his experiments with incandescent lamps in the late 1870s, that is, he worked on this project simultaneously with Lodygin and Yablochkov.
In April 1879, Edison experimentally came to the conclusion that without a vacuum, none of the incandescent lamps would work, or if they did, it would be extremely short-lived. And already in October of the same year, an American researcher completed work on a project for a carbon incandescent lamp, which is considered one of the most important inventions of the 19th century.
In 1882, together with several prominent financiers, the inventor founded the company Edison General Electric c, where they began to manufacture various electrical appliances. To win the market, Edison even went so far as to set the selling price of the lamp at 40 cents, despite the fact that its production cost 110 cents. Subsequently, the inventor suffered losses for four years, although he tried to reduce the cost of incandescent lamps. And when the cost of their production dropped to 22 cents, and the output reached a million pieces, he was able to cover all previous costs within a year, so that further production brought him only profit.
But what was Edison's innovation in inventing the incandescent lamp, other than the fact that he was the first to consider this subject as a means of making a profit? His merit lies not at all in the invention of lamps of this type, but in the fact that he was the first to create a practical and widespread system of electric lighting. And he came up with the modern, familiar shape of the lamp to all of us, as well as a screw base, socket and fuses.
Thomas Edison was distinguished by his high efficiency and always took a very responsible approach to business. So, in order to finally decide on the choice of material for the incandescent filament, he tried more than six thousand samples until he came to the conclusion that the most suitable material for this was carbonized bamboo.
Based on chronology, the inventor of the light bulb is Lodygin. It was he who invented the first lamp for lighting, and he was the first who guessed to pump out air from a glass bulb and use tungsten as an incandescent filament. Yablochkov’s “electric candle” is based on slightly different operating principles and does not require a vacuum, but for the first time, streets and premises began to be illuminated en masse with his candles. As for Edison, it was he who invented the lamp of modern forms, as well as the base, socket and fuses. Therefore, while giving the palm of invention to the first of these three inventors, the role of other researchers cannot be underestimated.
The answer to this seemingly elementary and simple question is still ambiguous. It is believed that the light bulb was invented in the not so distant 1879 by the American Thomas Edison. Well, or at least that's what our schoolchildren are taught.
But it’s worth looking into the issue and finding out: is this so? After all, in fact, the history of the well-known light bulb is a consistent chain of inventions and discoveries that were made at different times by different people.
- It is known for certain that the “progenitor” of the modern lamp appeared a long time ago. Since ancient times, attempts have been made to create devices capable of illuminating the darkness at night. And some attempts were quite successful and impressive. According to historical data:
- Not far from the Appian Way, a luminous lamp was discovered in one of the Roman tombs. It turns out that she worked, on average, 1,600 years.
- At the same time, a unique Pollanta lantern was discovered in another tomb in Rome. It shone for an average of 2,000 years.
- The “progenitor” of the light bulb was known to the Egyptians and the inhabitants of the Mediterranean. They were the first to use olive oil to illuminate their homes. It was poured into special clay vessels with inserted cotton wicks. An image of an object very reminiscent in its structure of an incandescent lamp was found in the Temple of Hathor, built by the ancient Egyptians.
- But the inhabitants of the Caspian Sea coast poured not olive oil, but oil into clay vessels.
- Data on the existence of intense and long-lasting lamps are found in famous authors of various eras. In particular, Aurelius Augustine, Plutarch, Lucian, Pausanias and many others wrote about them. Cyrano de Bergerac also wrote about the “eternal lamp” in his works.
In the Middle Ages, clay vessels were replaced by the first candles, which included natural beeswax and lard. Further, over the centuries, many of the greatest scientists, geniuses and inventors of our Earth worked on the invention of a lighting device that was safe for humans.
Nevertheless, the first safe design suitable for mass production appeared approximately in the mid-19th century.At this time, a wave of various discoveries closely related to electricity swept across the world. We can say that a kind of chain reaction began: one relatively small discovery paved the way for even larger plans and grandiose ideas.
“Authors” of light bulbs from different countries
Vasily Petrov (Russia)
In 1803, he produced an electric arc using a capacitive battery. Having constructed this huge and very powerful battery, he was the first in the world to declare that an electric voltaic arc can illuminate objects and rooms at night. It was difficult for the discoverer to conduct experiments, since the charcoal used as an electrode burned out in a matter of minutes.
British inventor Delarue
Work on creating and improving the light bulb continued. In 1809, a Briton designed the world's first model of a lamp with an incandescent filament, which was made of platinum. But the platinum spiral was too fragile and at the same time too expensive. Therefore, it did not receive recognition and active dissemination.
Belgian scientist Jobard
Considering the shortcomings of previous light bulb designs, he set out to optimize and in 1938 introduced the carbon incandescent lamp to the world. But his lamp also had a flaw: it contained oxygen, so the carbon rod burned out quite quickly.
Jean Bernard Foucault (France)
Taking over the “baton,” a scientist from France in 1844 replaced charcoal electrodes in an arc lamp with retort carbon electrodes. He also equipped the lamp with manual control of the arc length, while the source of electricity was a fairly powerful battery for that time.
Heinrich Goebel (Germany)
The light bulb continued to change. The “author” of the first modern lamp was a scientist from Germany, who in 1855 placed a charred bamboo thread in a vacuum container. The lamp was still far from perfect, but it had become more practical.
Alexander Lodygin (Russia)
In 1874, he patented a unique filament lamp. The scientist placed a stick of coal in a evacuated flask. Tungsten served as the material for filaments. Thanks to this, it was possible to significantly extend the life of these lamps.
Vasily Didrikhson (Russia)
Having improved the design of his compatriot, in 1875 he pumped out the air from the lamp. In addition, this time the scientist used several hairs so that if one of them burns out, the next hair starts working automatically.
Pavel Yablochkov (Russia)
Through his efforts, long and fruitful experiments grew into mass electric lighting. In 1875, he came up with the idea of creating a simple and at the same time very reliable arc lamp. In 1876 and 1877, he received several patents: for the design of the arc lamp itself, as well as for their power supply systems.
Production was soon put on an industrial basis, but gradually the Yablochkov Candle was replaced by a more durable, modern and economical incandescent lamp.
Joseph Wilson Swan (England)
Against the background of these discoveries, in 1878 an Englishman patented a slightly different lamp. In his invention, he placed carbon fiber in a rather rarefied oxygen atmosphere. Thanks to this, the light from the lamp became noticeably brighter.
Thomas Edison (USA)
He refined and optimized technologies that already existed at that time. In 1880, he patented a coal lamp that was capable of shining for about 40 hours. He also managed to significantly reduce the cost of the lamp. Soon his lamps replaced gas lighting.
Thus, a significant contribution was made to the development of technology by several hardworking scientists and inventors from Germany, Russia, Belgium, the USA, France, England and other countries. That is why some attribute the authorship directly to Thomas Edison, while others are firmly convinced that Alexander Lodygin is right.
Undoubtedly, the lamp was invented long before the American patented it. However, his enormous and undeniable merit is that, combining all the best, he opened the practical lamp to the world along with the electrical system. It is for this achievement that he is usually credited with being the first author of the light bulb.
And finally, an interesting video where a girl “investigates” the invention of lamps.
The question of who first developed the idea of the light bulb again and again gives rise to various theories.
There are so many options that every nation strives to attribute this merit to its compatriots.
The idea of a constant light source dates back to the early 19th century. During this period, scientists all over the world created various projects.
So in 1820, the French scientist Delacru created the first copy of an electric light bulb with a platinum wire. When an electric current was passed through it, the thread glowed and gave off light.
Unfortunately, this expensive metal (platinum) was not available for mass production and remained a sample of an experimental laboratory.
Heinrich Goebel
In the second half of the 19th century, the German scientist Heinrich Goebel first proposed pumping air out of a lamp.
This allowed it to burn much longer. His project still required additional work and was not continued.
Yablochkov
At the same time, the invention of the Russian experimental mechanic Yablochkov was gaining momentum on the streets of France.
His candles in the lanterns illuminated the city streets. Automatic replacement of lamps made it possible to increase the burning time to one and a half hours.
A. N. Lodygin
In 1872, the tests of the scientist A. N. Lodygin were crowned with success. His newest invention was radically different from all previous ones. The cost of producing the light bulb was minimal.
The carbon filament rod allowed the lamp to burn for about half an hour. Lodygin received a patent for his invention, and soon his lamps began to illuminate the streets of St. Petersburg.
Subsequently, interest in his work subsides. The scientist made every effort, but never achieved worldwide fame.
Thomas Edison
Thomas Edison became Lodygin's competitor in the 1870s. It was he, in collaboration with other famous scientists and an American energy company, who improved the well-known model and thus obtained a new invention.
The incandescent lamp has become an integral part of everyday life in every home. The device we are familiar with was obtained through the efforts of many scientists.
The continuity of their inventions gave rise to discussions about the right of primacy that continue to this day.
But we will not belittle the merits of any of the scientists, since everyone is worthy of glory.
The electric incandescent lamp has long become an object without which it is difficult to imagine our lives. In the evening, when entering a house or apartment, the first thing we do is flip the switch in the hallway and within a moment a bright light flashes, dispelling the darkness around us. And at the same time, we don’t think about where such an ordinary light bulb came to us from and who invented the light bulb. The electric lamp has long become commonplace for us, but once upon a time it was akin to a real miracle.
Before the invention of electricity, people lived in twilight. With the onset of darkness, the dwellings were plunged into darkness and their inhabitants, in order to somehow disperse the darkness that frightened them, lit a fire.
To illuminate houses in different countries, lamps of various designs, torches, candles, and torches were used, and fires were lit in the open air, for example, on the road or in military camps. People treasured these light sources; they invented legends and composed songs about them.
However, the inquisitive human mind already in ancient times was looking for an alternative to all these devices. After all, they all gave little light, smoked heavily, filling the room with smoke, and besides, they could go out at any minute. Archaeologists who discovered amazing paintings inside the ancient Egyptian pyramids could not help but wonder how the ancient artists made these drawings despite the fact that natural light did not penetrate into the pyramids, and no soot was found on the walls and ceiling from torches or lamps. It is likely that the answer to this question has already been found in the city of Dendera, in the temple of the goddess Hathor. It is there that there are bas-reliefs, which may depict an ancient electric lamp similar to a gas-discharge lamp.
In the 9th century AD. In the Middle East, an oil lamp was invented, which became the prototype of a kerosene lamp, but it did not become widespread and remained a rare curiosity.
Thus, until the middle of the 19th century, the most popular light sources remained oil and fat lamps, candles, lanterns and torches, and in camp conditions - the same fires as in ancient times.
The kerosene lamp, invented in the middle of the 19th century, supplanted all other sources of artificial lighting, although not for long: until the electric light bulb appeared - the most common for us, but absolutely amazing for the people of that time.
At the dawn of discovery
The operation of the first incandescent lamps was based on the principle that conductors glow when electric current is passed through them. This very property of such materials was known long before the invention of the light bulb. The problem was that for a very long time the inventors could not find a suitable material for an incandescent filament that would provide long-lasting and effective, and also inexpensive lighting.
Background to the appearance of incandescent lamps:
Who first invented the light bulb
In the 1870s, serious work began on the invention of the electric light bulb. Many prominent scientists and inventors devoted years and decades of their lives to working on this project. Lodygin, Yablochkov and Edison - these three inventors worked in parallel on the design of incandescent lamps, so disputes still continue about which of them can be considered the world's first inventor of the incandescent electric lamp.
Lamp by A. N. Lodygin
He began his experiments on the invention of the incandescent lamp in 1870 after his retirement. At the same time, the inventor was simultaneously working on several projects: creating an electric plane, a diving apparatus and a light bulb.
In 1871-1874, he conducted experiments to find the most suitable material for an incandescent coil. Having initially tried to use iron wire and failed, the inventor began experimenting with a carbon rod placed in a glass container.
In 1874, Lodygin received a patent for the incandescent lamp he invented, not only Russian, but also international, patenting his invention in many European countries and even in India and Australia.
In 1884, for political reasons, the inventor left Russia. For the next 23 years he worked alternately in France and in the USA. Even in exile, he continued to develop new designs for incandescent lamps, patenting those that used refractory metals as the material for the spiral. In 1906, Lodygin sold these patents to the General Electric Company in the USA. During his research, the inventor came to the conclusion that the best materials for incandescent filaments are tungsten and molybdenum. And the first incandescent lamps produced in the USA were made according to his design and with tungsten filament.
Yablochkov's lamp P.N.
In 1875, finding himself in Paris, he began inventing an arc lamp without a regulator. Yablochkov had begun work on this project even earlier, while living in Moscow, but failed. The capital of France became the city where he was able to achieve outstanding results.
By the beginning of the spring of 1876, the inventor completed work on the design of an electric candle, and on March 23 of the same year he received a patent for it in France. This day became significant not only in the fate of P. N. Yablochkov himself, but also a turning point for the further development of electrical and lighting engineering.
Yablochkov's candle was simpler and cheaper to operate than Lodygin's coal lamp. In addition, it did not have any springs or any mechanisms. It looked like two rods clamped in two separate terminals of a candlestick, which were separated by a kaolin partition, isolating them from each other. An arc charge was ignited at the upper ends, after which the arc flame slowly burned the coal and vaporized the insulating material, at the same time emitting a bright glow.
Later, Yablochkov tried to change the color of the lighting, for which he added salts of various metals to the insulating material for the partition.
In April 1876, the inventor demonstrated his candle at an electrical exhibition in London. The large audience was delighted with the bright bluish-white electric light that flooded the room.
The success was incredible. The scientist and his invention were written about in the foreign press. And already at the end of the 1870s, streets, shops, theaters, hippodromes, palaces and mansions were illuminated with electric candles not only in Europe, but also in the USA, Brazil, Mexico, India, Burma and Cambodia. And in Russia, the first test of Yablochkov’s electric candles took place in the fall of 1878.
It was a real triumph for the Russian inventor. After all, before his candle, there was not a single invention in the field of electrical engineering that would so quickly become popular throughout the world.
Edison lamp T.A.
He conducted his experiments with incandescent lamps in the late 1870s, that is, he worked on this project simultaneously with Lodygin and Yablochkov.
In April 1879, Edison experimentally came to the conclusion that without a vacuum, none of the incandescent lamps would work, or if they did, it would be extremely short-lived. And already in October of the same year, an American researcher completed work on a project for a carbon incandescent lamp, which is considered one of the most important inventions of the 19th century.
In 1882, together with several prominent financiers, the inventor founded the company Edison General Electric c, where they began to manufacture various electrical appliances. To win the market, Edison even went so far as to set the selling price of the lamp at 40 cents, despite the fact that its production cost 110 cents. Subsequently, the inventor suffered losses for four years, although he tried to reduce the cost of incandescent lamps. And when the cost of their production dropped to 22 cents, and the output reached a million pieces, he was able to cover all previous costs within a year, so that further production brought him only profit.
But what was Edison's innovation in inventing the incandescent lamp, other than the fact that he was the first to consider this subject as a means of making a profit? His merit lies not at all in the invention of lamps of this type, but in the fact that he was the first to create a practical and widespread system of electric lighting. And he came up with the modern, familiar shape of the lamp to all of us, as well as a screw base, socket and fuses.
Thomas Edison was distinguished by his high efficiency and always took a very responsible approach to business. So, in order to finally decide on the choice of material for the incandescent filament, he tried more than six thousand samples until he came to the conclusion that the most suitable material for this was carbonized bamboo.
Based on chronology, the inventor of the light bulb is Lodygin. It was he who invented the first lamp for lighting, and he was the first who guessed to pump out air from a glass bulb and use tungsten as an incandescent filament. Yablochkov’s “electric candle” is based on slightly different operating principles and does not require a vacuum, but for the first time, streets and premises began to be illuminated en masse with his candles. As for Edison, it was he who invented the lamp of modern forms, as well as the base, socket and fuses. Therefore, while giving the palm of invention to the first of these three inventors, the role of other researchers cannot be underestimated.