The history of incandescent lamps dates back to the nineteenth century. Consider the main points associated with this unique invention of mankind.
Peculiarities
An incandescent light bulb is an item that is familiar to many people. At present, it is difficult to imagine the life of mankind without the use of artificial and electric light. At the same time, rarely does anyone think about how the first lamp looked like, in what historical period it was created.
To begin with, consider the device of an incandescent lamp. This electric light source is a high melting point conductor that is found in a bulb. Air is previously pumped out of it, instead of it the flask is filled with an inert gas. Passing through the lamp, an electric current emits a stream of light.
The essence of functioning
What is the working principle of an incandescent lamp? It lies in the fact that when flowing electric current through the filament, the element heats up, while the tungsten filament itself heats up. It is she who emits radiation of the thermal and electromagnetic type according to Planck's law. To create a full-fledged glow, you need to heat the tungsten filament to several hundred degrees. As the temperature decreases, the spectrum turns red.
The first incandescent lamps had many disadvantages. For example, it was difficult to regulate the temperature, as a result of which the lamps quickly failed.
Technical features
What is the construction of a modern incandescent lamp? Since she became the first light source, she has enough simple construction... The main elements of the lamp are:
- glow body;
- flask;
- current inputs.
At present, various modifications have been developed, a fuse is introduced into the lamp, which is a link. For the production of this part, an iron-nickel alloy is used. The link is welded into the current input leg in order to prevent the destruction of the glass bulb when the tungsten filament is heated.
Considering the main advantages and disadvantages of incandescent lamps, we note that since their inception, the lamps have been significantly modernized. For example, the use of a fuse has reduced the likelihood of rapid lamp rupture.
The main disadvantage of such lighting elements is their high energy consumption. That is why they are now used much less frequently.
How artificial light sources appeared
The history of incandescent lamps is associated with many inventors. Until the time when the Russian physicist Alexander Lodygin began to work on its creation, the first models of incandescent lamps had already been developed. In 1809, the English inventor Delarue developed a model that was fitted with a platinum coil. The history of incandescent lamps is also associated with the inventor Heinrich Gebel. In a sample created by a German, a charred bamboo thread was placed in a vessel, from which air was first pumped out. Gebel has been modernizing his incandescent lamp model for fifteen years. He managed to get a working version of the incandescent light bulb. Lodygin achieved a high-quality glow of a coal rod placed in glass vessel from which air has been removed.
Practical model variant
The first incandescent lamps that could be produced in large quantities appeared in England at the end of the nineteenth century. Joseph Wilson Swan even managed to get a patent for his own design.
Speaking about those who invented the incandescent lamp, it is also necessary to dwell on the experiments conducted by Thomas Edison.
He tried to use as filaments various materials... It was this scientist who proposed a platinum filament as a filament.
This invention of the incandescent lamp marked a new stage in the field of electricity. Initially, Edison's lamps only functioned for forty hours, but despite this, they quickly replaced gas lighting.
During the period when Edison was engaged in his research, in Russia Alexander Lodygin managed to create several different types lamps in which the role of filaments was played by refractory metals.
The history of incandescent lamps testifies to the fact that it was the Russian inventor who first began to use refractory metals in the form of an incandescent body.
In addition to tungsten, Lodygin also experimented with molybdenum, twisting it in a spiral.
The specifics of the Lodygin lamp
Modern analogs are characterized by excellent luminous flux, as well as high-quality color rendition. Their efficiency is 15% at the highest heating temperature. Such light sources consume a significant amount of electrical energy, therefore, their operation is carried out for no more than 1000 hours. This is more than compensated for by the low cost of lamps, therefore, despite the variety of artificial light sources presented on modern market, they are still considered popular and in demand among buyers.
Interesting facts from the history of the incandescent lamp
At the end of the nineteenth century, Didrichson managed to make significant changes to the model proposed by the Russian inventor Lodygin. He completely evacuated air from it, used several hairs in the lamp at once.
This improvement made it possible to use the lamp even when one of the hairs burned out.
English engineer Joseph Wilson Swan owns a patent confirming his creation of a carbon fiber lamp.
The fiber was positioned in a rarefied oxygen atmosphere, as a result of which the light was brighter and more uniform.
In the second half of the nineteenth century, in addition to the lamp itself, Edison invented a rotary switch for household appliances.
Large-scale appearance of lamps on the market
From the end of the nineteenth century, lamps began to appear in which oxides of yttrium, zirconium, thorium, magnesium were used as filament.
At the beginning of the last century, Hungarian researchers Sandor Yust and Franjo Hanaman received a patent for the use of a tungsten filament in incandescent lamps. It was in this country that the first copies of such lamps were made, which entered the large-scale market.
In the USA, in the same time period, plants were built and launched, engaged in the production of titanium, tungsten, chromium, by means of electrochemical reduction.
The high cost of tungsten has made adjustments to the rate at which incandescent lamps are introduced into everyday life.
In 1910, Coolidge developed new technology the manufacture of thin tungsten filaments, which contributed to the reduction in the cost of production of artificial incandescent lamps.
The problem of its rapid evaporation was solved by the American scientist Irving Langmuir. It was he who introduced into industrial production the filling of glass flasks with inert gas, which increased the life of the lamp and made them cheaper.
Efficiency
Almost all the energy that is received in the lamp gradually turns into thermal radiation. The efficiency reaches 15 percent at temperature indicator 15 percent.
As the temperature rises, the efficiency increases, but this causes a significant decrease in the operating life of the lamp.
At 2700 K, the full-fledged use of an artificial light source is 1000 hours, and at 3400 K - several hours.
In order to increase the durability of the incandescent lamp, the developers propose to reduce the value of the supply voltage. Of course, in this case, the efficiency will also decrease by about 4-5 times. Engineers use this effect in cases where reliable lighting of minimum brightness is required. For example, this is true for evening and night lighting. construction sites, flights of stairs.
To do this, carry out a serial connection alternating current lamps with a diode, which guarantees the supply of current to the lamp for half of the entire period of current supply.
Considering that the price of an ordinary incandescent lamp is significantly less than its average service life, the purchase of such lighting sources can be considered a rather profitable measure.
Conclusion
The history of the appearance of that model of an electric lamp, to which we are accustomed, is associated with the names of many Russian and foreign scientists and inventors. Over the course of two centuries, this artificial source of illumination has undergone transformations, modernizations, the purpose of which was to increase the operational life of the device and reduce its cost.
The greatest wear on the filament occurs when the voltage is suddenly applied to the lamp. To solve this problem, inventors began to equip lamps with a variety of devices to ensure their smooth start.
Cold tungsten filament has a resistivity that is only twice that of aluminum. To avoid power peaks, designers use thermistors whose resistance decreases as the temperature rises.
For low-voltage lamps with equal power, the service life and luminous efficiency are much higher, since they have a larger section of the incandescent body. In luminaires designed for multiple lamps, it is effective to connect several lamps of lower voltage in series. For example, instead of six 60 W lamps connected in parallel, you can use only three.
Certainly, these days there have appeared different models electric lamps, which have much more effective characteristics than ordinary light bulbs invented during the time of Lodygin and Edison.
Hello everyone. Glad to see you on my website. Topic of today's article: the device of an incandescent lamp. But first I would like to say a few words about the history of this lamp.
The very first incandescent light bulb was invented by the English scientist Delarue back in 1840. It had a platinum coil. A little later, in 1854, the German scientist Heinrich Goebel presented a lamp with a bamboo filament, which was located in a vacuum flask. At that time, there were still a lot of different lamps presented by various scientists. But they all had a very short term services, and were not efficient.
In 1890, the scientist A.N. Lodygin presented for the first time a lamp with a tungsten filament and had the form of a spiral. This scientist also made attempts to evacuate air from the flask and fill it with gases. This significantly increased the life of the lamps.
But the serial production of incandescent lamps began in the 20th century. Then it was a real breakthrough in technology. Now, in our time, many enterprises, and simply ordinary people refuse these lamps due to the fact that they consume a lot of electricity. And in some countries they even banned the production of incandescent lamps with a capacity of more than 60 watts.
Incandescent lamp device.
Such a lamp consists of the following parts: base, bulb, electrodes, hooks for holding the filament, filament, plug, insulating material, contact surface.
In order to make it clearer for you, I will now write about each detail separately. Also see the picture and video.
Flask - made from ordinary glass and is needed to protect the filament from external environment... A plug with electrodes and hooks that hold the thread itself is inserted into it. A vacuum is specially created in the flask, or it is filled with a special gas. This is usually argon, as it does not lend itself to heating.
On the side where the electrode leads are located, the bulb is melted with glass and glued to the base.
The base is needed so that the bulb can be screwed into the socket. It is usually made from aluminum.
An incandescent filament is a part that emits light. Manufactured mainly from tungsten.
And now, to consolidate your knowledge, I suggest you look very interesting video, which explains and shows how incandescent bulbs are made.
Operating principle.
The principle of operation of an incandescent lamp is based on heating the material. It is not for nothing that the filament has such a name. If an electric current is passed through a light bulb, the tungsten filament heats up to a very high temperature and begins to emit a luminous flux.
The filament does not melt, because tungsten has a very high melting point, somewhere between 3200-3400 degrees Celsius. And when the lamp is working, the filament heats up somewhere up to 2600-3000 degrees Celsius.
Advantages and disadvantages of incandescent lamps.
Main advantages:
Not a high price.
Small size.
Easily tolerate voltage drops in the network.
When turned on, it instantly lights up.
Flickering is almost imperceptible to the human eye when operating on AC power.
You can use the device to adjust the brightness.
Can be used at both low and high ambient temperatures.
Such lamps can be produced for almost any voltage.
It does not contain hazardous substances in its composition, and therefore does not need special disposal.
No triggering devices are required to ignite the lamp.
It can work on AC and DC voltage.
It is very quiet and does not cause radio interference.
And this is far from full list benefits.
Flaws:
Has a very short service life.
Very low efficiency. Usually it does not exceed 5 percent.
Luminous flux and service life directly depend on the mains voltage.
The lamp housing gets very hot during operation. Therefore, such a lamp is considered fire hazardous.
If the filament breaks, the bulb may explode.
Very fragile and shock-sensitive.
It breaks down very quickly under vibration conditions.
And at the end of the article, I would like to write about one amazing fact... In the United States, in one of the fire departments in the city of Livermore, there is a 60-watt lamp that has been glowing continuously for over 100 years. It was lit back in 1901, and in 1972 it was entered into the Guinness Book of Records.
The secret of its longevity is that it works in deep undershoot. By the way, the work of this lamp is continuously recorded by the webcam. So anyone interested can look for a live broadcast on the Internet.
That's all for me. If the article was useful to you, then share it with your friends in in social networks and subscribe to updates. Till.
Sincerely, Alexander!
A body heated by an electric current, it turns out, can not only emit heat, but also glow. The first light sources functioned precisely on this principle. Let's take a look at how an incandescent lamp, the most widely used lighting fixture in the world, works. And, although it will eventually have to be completely replaced by compact fluorescent (energy-saving) and LED light sources, mankind will not be able to do without this technology for a long time.
Incandescent lamp design
The main element of the light bulb is a spiral made of a refractory material - tungsten. To increase its length and, accordingly, resistance, it is twisted into a thin spiral. It is not visible to the naked eye.
The spiral is fixed on supporting elements, the outermost of which are used to connect its ends to the electrical circuit. They are made of molybdenum, the melting point of which is higher than the temperature of the heated coil. One of the molybdenum electrodes is connected to the threaded part of the base, and the other - to its central outlet.
Molybdenum holders hold the tungsten coil
Air is pumped out of a flask made of glass. Sometimes, instead of air, an inert gas is pumped inside, for example, argon or its mixture with nitrogen. This is necessary to reduce the thermal conductivity of the internal volume, as a result of which the glass is less susceptible to heating. In addition, this measure prevents oxidation of the filament. When making a lamp, air is pumped out through a part of the bulb, then hidden by the base.
The principle of operation of an incandescent lamp is based on the heating of its filament by an electric current to the temperature at which it begins to emit light into the surrounding space.
Incandescent lamps can be manufactured with power from 15 to 750 W. Depending on the power, they are used different types threaded plinths: E10, E14, E27 or E40. For decorative, signal and backlight lamps, the bases BA7S, BA9S, BA15S are used. When installed, such products are stuck inside the cartridge and rotated 90 degrees.
In addition to the usual, pear-shaped, also decorative lamps, in which the bulb is made in the form of a candle, drop, cylinder, ball.
A lamp with an uncoated bulb glows with a yellowish light, the composition most reminiscent of the sun. But when special coatings are applied to the inner surface of the glass, it can become dull, red, yellow, blue or green.
Of interest is the device of an incandescent mirror lamp. A reflective layer is applied to part of its bulb. As a result, due to reflection from it, the luminous flux is redistributed in one direction.
Advantages of incandescent lamps
The most important advantage in favor of using incandescent bulbs is the ease of their manufacture and, accordingly, the price. It is impossible to come up with a simpler lighting device.
Lamps are manufactured for a wide range of powers and dimensions. All other modern light sources contain devices that convert the supply voltage to the value necessary for their operation. Although they manage to fit them into the standard overall dimensions of the light bulb, the design becomes more complicated and the number of parts in the device increases. And this does not always improve cost and reliability indicators. The incandescent lamp switching circuit does not require any additional elements.
LED bulbs have superseded the conventional portable devices: portable light sources powered by batteries and rechargeable batteries. With the same light output, they consume less current, and the overall dimensions of the LED are even smaller than the bulbs previously used in flashlights. Yes, and in the composition Christmas tree garlands they work better.
It is worth noting one more advantage inherent in incandescent light bulbs - their glow spectrum is closest to that of the sun than all other artificial light sources. And this is a big plus for vision, because it is adapted specifically to the sun, and not to monochrome LEDs.
Due to the thermal inertia of the heated filament, the light from it practically does not pulsate. The same cannot be said about radiation from other devices, especially luminescent ones, using a conventional choke as a ballast, and not a semiconductor circuit. And electronics, especially cheap ones, do not always suppress the ripple from the mains properly. This also affects vision.
But not only health can damage the pulsating nature of the semiconductor devices used in modern light bulbs... Their massive use leads to a sharp change in the shape of the current consumed from the network, which ultimately affects the shape of the voltage. It changes so much in relation to the original (sinusoidal) that it affects the quality of the work of other electrical appliances in the network.
Disadvantages of incandescent bulbs
A significant drawback of incandescent bulbs, which reduces their service life, is its dependence on the magnitude of the supply voltage. When the voltage is increased, the wear of the filament is faster. They produce lamps for different values of this parameter (up to 240 V), but at the nominal value they shine worse.
Lowering the voltage leads to a sharp change in the glow intensity. And even worse, its vibrations affect the lighting device; with sudden jumps, the lamp can burn out.
But the worst thing is that the filament is designed to long work in a heated state. When heated, its resistivity increases. Therefore, at the moment of switching on, when the thread is cold, its resistance is much less than that at which the glow occurs. This leads to an inevitable surge in current at the moment of ignition, leading to the evaporation of tungsten. How more quantity inclusions - the less the lamp will live.
Devices for a smooth start or that allow you to adjust the brightness of the glow over a wide range help to correct the situation.
The main disadvantage of incandescent light bulbs is their low efficiency. The overwhelming part of electricity (up to 96%) is spent on useless heating of the surrounding air and radiation in the infrared spectrum. Nothing can be done about this - this is the principle of operation of an incandescent lamp.
And one more thing: the glass of the flask is easy to break. But unlike compact fluorescent ones, containing a small amount of mercury vapor inside, a broken incandescent lamp, apart from a possible cut, does not threaten the owner.
Halogen lamps
The cause of incandescent lamp burnout is the gradual evaporation of the tungsten from which the filament is made. It becomes thinner, and then the next surge in current, when turned on, melts it in the thinnest place.
This disadvantage is intended to eliminate halogen lamps filled with bromine or iodine vapor. During combustion, the evaporated tungsten combines with the halogen. The resulting substance is not capable of settling on the walls of the flask or other, relatively cold, internal surfaces.
In the vicinity of the filament, the tungsten is removed from the joint under the influence of temperature and returned to its place.
The use of halogens solves another problem: the temperature of the coil can be raised, increasing the luminous efficiency and reducing the size of the lighting device. Therefore, at the same power, the dimensions of halogen lamps are smaller.
Modern market lighting fixtures today it is represented not only by a variety of lamps, but also by light sources. Incandescent lamps (incandescent lamps) are among the oldest light bulbs of our time.
Even taking into account the fact that today there are more advanced light sources, incandescent lamps are still widely used by people to illuminate various kinds of premises. Here we will consider such an important parameter of these lamps as the heating temperature during operation, as well as the color temperature.
Light source features
Incandescent light bulbs represent the very first source of electric light that was invented by man... These products can be of different power (from 5 to 200 W). But the most commonly used models are 60 watts.
Note! The biggest disadvantage of incandescent lamps is their high power consumption. Because of this, the number of LNs, which are actively used as a light source, decreases every year.
Before proceeding to consider such parameters as heating temperature and color temperature, it is necessary to understand the design features of such lamps, as well as in the principle of its operation.
An incandescent lamp, in the course of its operation, converts electrical energy passing through a tungsten filament (spiral) into light and heat.
Today, radiation, in its own way physical characteristics, is divided into two types:
Incandescent lamp device
- thermal;
- luminescent.
Thermal, which is typical for incandescent lamps, means light emission. It is on thermal radiation that the glow is based light bulb incandescent.
Incandescent lamps consist of:
- glass flask;
- refractory tungsten filament (part of the spiral). An important element the entire lamp, since if the filament is damaged, the lamp stops glowing;
- basement.
During the operation of such lamps, an increase in t0 of the filament occurs due to the passage of electric energy through it in the form of a current. To avoid rapid burnout of the filament in the spiral, air is pumped out of the flask.
Note! In more advanced models of incandescent lamps, which are halogen bulbs, instead of a vacuum, an inert gas is pumped into the bulb.
The installation of the tungsten filament takes place in a spiral, which is fixed on the electrodes. In a spiral, the thread is in the middle. The electrodes to which the spiral and the tungsten filament are installed, respectively, are soldered to different elements: one to the metal sleeve of the base, and the other to the metal contact plate.
As a result of this design of an electric bulb, the current passing through the spiral causes heating (increase in t0 inside the bulb) of the filament, since it overcomes its resistance.
How a light bulb works
Working incandescent lamp
Heating of the LN during operation occurs due to design features light source. It is because of the strong heating during operation that the operating time of the lamps is significantly reduced, which makes them not so profitable today. In this case, due to heating of the filament, t0 of the flask itself increases.
The principle of operation of the LN is based on the conversion of electrical energy that passes through the filaments of the spiral into light radiation. In this case, the temperature of the heated filament can reach 2600-3000 ° C.
Note! The melting temperature for tungsten, from which the filaments are made, is 3200-3400 ° C. As you can see, normally the heating temperature of the thread cannot lead to the beginning of the melting process.
The spectrum of lamps with this structure differs markedly from the spectrum of daylight. For such a lamp, the spectrum of the emitted light will be characterized by a predominance of red and yellow rays.
It should be noted that the flasks have more modern models LN (halogen) are not evacuated, and also do not contain a spiral thread. Instead, inert gases (argon, nitrogen, krypton, xenon and argon) are pumped into the flask. These design improvements have led to a slight decrease in the heating temperature of the bulb during operation.
Light source advantages and disadvantages
Despite the fact that today the market for light sources abounds in a wide variety of models, incandescent lamps are still found quite often on it. Here you can find products on different amount W (5 to 200 W and above). The most demanded bulbs are from 20 to 60 watts, as well as 100 watts.
Assortment of choice
LNs continue to be widely used because they have their own advantages:
- when turned on, the ignition of the light occurs almost instantly;
- small size;
- low cost;
- models with only vacuum inside the flask are environmentally friendly products.
It is these advantages that determined the fact that LN are still quite in demand in modern world... In homes and in production today, you can easily find representatives of this lighting product for 60 W and above.
Note! A large percentage of LN is used in industry. Powerful models (200 W) are often used here.
But incandescent lamps also have a fairly impressive list of disadvantages, which include:
- the presence of a blinding brightness of the light emanating from the lamps during operation. As a result, the use of special protective screens is required;
- during operation, heating of the thread is observed, as well as the flask itself. Due to the strong heating of the flask, if even a small amount of water hits its surface, an explosion is possible. Moreover, the heating of the bulb occurs in all light bulbs (at least by 60 W, at least lower or higher);
Note! An increase in the heating of the bulb still carries a certain degree of danger of injury. The increased temperature of the glass bulb, if touched with unprotected areas of the skin, can cause burns. Therefore, such lamps should not be placed in those lamps that a child can easily reach. In addition, damage to the glass bulb can cause cuts or other injuries.
Tungsten filament heating
- high power consumption;
- in case of failure, they cannot be repaired;
- low service life. Incandescent lamps quickly fail due to the fact that at the moment the light is turned on or off, the filament of the spiral can be damaged due to frequent heating.
As you can see, the use of LN has many more disadvantages than advantages. The most important disadvantages of incandescent legs are considered to be heating due to an increase in the temperature inside the bulb, as well as high energy consumption. Moreover, this applies to all versions of lamps with a power of 5 to 60 W and above.
Important evaluation parameters
One of the most important parameters of LN operation is the light coefficient. This parameter has the form of the ratio of the radiation power of the visible spectrum and the power of the consumed electricity. For this product, this is a fairly small value, which does not exceed 4%. That is, LN is characterized by low light output.
Other important performance parameters include:
- light flow;
- color t0 or glow color;
- power;
- life time.
Let's consider the first two parameters, since we figured out the service life in the previous paragraph.
Light flow
The luminous flux is physical quantity, which determines the amount of light power in a particular flux of light emission. In addition to this, there is one more important aspect like light output. It determines for the lamp the ratio of the luminous flux emitted by the lamp to the power that it consumes. Luminous efficacy is measured in lm / W.
Note! Luminous efficiency is an indicator of the economy and efficiency of light sources.
Luminous flux and luminous efficacy table for incandescent lamps
As you can see, for our light source, the above values are at a low level, which indicates their low efficiency.
Glow color of bulbs
Color temperature (t0) is also an important indicator.
The color t0 is a characteristic of the course of the light intensity of the lamp and is a function of the wavelength defined for the optical range. This parameter is measured in kelvin (K).
Color temperature for incandescent lamp
It is worth noting that the color temperature for LN is approximately at the level of 2700 K (for light sources with a power of 5 to 60 W and above). The color t0 LN is in the red and thermal tint regions of the visible spectrum.
The color t0 fully corresponds to the degree of heating of the tungsten filament, which prevents the LN from quickly failing.
Note! For other light sources (such as LED bulbs), the color temperature does not indicate how much they have warmed up. With the LN heating parameter of 2700 K, the LED warms up by only 80 ° C.
Thus, the more the LN power is (from 5 to 60 W and higher), the more heating of the tungsten filament and the bulb itself will occur. Accordingly, the larger the color t0 will be. Below is a table by which you can compare efficiency and power consumption different types light bulbs. As the control group, with which the comparison is made, here are taken LN with a power from 20 to 60 and up to 200 W.
Comparative table of powers of different light sources
As you can see, incandescent lamps in this parameter are significantly inferior in terms of power consumption to other light sources.
Lighting technology and glow color
In lighting engineering, the most important parameter for a light source is its color t0. Thanks to it, you can determine the color tone and chromaticity of light sources.
Color temperature options
The color t0 of bulbs is determined by the color tone and is of three types:
- cold (from 5000 to 120,000K);
- neutral (from 4000 to 50,000K);
- warm (from 1850 to 20000K). It is given by a stearic candle.
Note! Considering the color temperature of LN, it should be remembered that it does not coincide with the actual thermal temperature of the product, which is felt when touched with a hand.
For LN, the color temperature ranges from 2200 to 30,000K. Therefore, they can have radiation close to ultraviolet.
Conclusion
For all types of light sources important parameter the evaluation is the color temperature. Moreover, for LN, it serves as a reflection of the degree of heating of the product during its operation. Such bulbs are characterized by an increase in the heating temperature during operation, which is a clear disadvantage that modern light sources, such as LED bulbs, lack. Therefore, today many people give their preference to fluorescent and LED bulbs, and incandescent bulbs are gradually becoming a thing of the past.
How does an incandescent light bulb work?
A retro light bulb is a beautiful thing, no doubt about it. But how does it all work? How is an Edison bulb different from a regular bulb? To be honest, almost nothing. Now let's put everything on the shelves.
First, the definition.Incandescent lamp- Light source , in which light is emitted by a spiral, it is a filament, it is also a filament, heated by an electric current to a high temperature. The most commonly used spiral is made of a refractory metal, for example tungsten , or charcoal thread. To exclude the oxidation of the glowing body upon contact with air, it is placed in a vacuum, pumping air out of the glass bulb.
Operating principle
In any incandescent lamp, whether it is ordinary or retro light bulb, the effect of heating the conductor when flowing through it is used electric current... The filament temperature rises after the electrical circuit is closed. To obtain visible radiation, it is necessary that the temperature of the emitting body exceed 570 degrees (the temperature of the beginning of the red glow, visible to the human eye in the dark). For human vision, the optimal, physiologically most convenient, spectral composition of visible light corresponds to radiation with a surface temperature of the solar photosphere of 5770 K. However unknown solids, capable of withstanding the temperature of the solar photosphere without destruction, therefore the operating temperatures of filaments of incandescent lamps are in the range of 2000-2800 C. Refractory and relatively inexpensive tungsten is used in the incandescent bodies of modern incandescent lamps ( melting temperature 3410 ° C), rhenium and (very rarely) osmium. Therefore, the spectrum of incandescent lamps is shifted to the red part of the spectrum. Only a small fraction electromagnetic radiation lies in the region of visible light, the main share falls on infrared radiation and is perceived as heat... The lower the incandescent body temperature, the lower the proportion energy supplied to the heated wire is converted into useful visible radiation , and the more "red" the radiation seems. Accordingly, retro light bulbs differ from ordinary ones in that they heat up the filament weaker. This allows the filament to evaporate more slowly and last longer.
Retro light bulbs, by the way, are also useful. At temperatures typical for incandescent lamps, 2200-2900 K, a yellowish light is emitted that is different from daylight. V evening time"warm" (< 3500 K) свет более комфортен для человека и меньше подавляет естественную выработку melatonin, important for regulation daily cycles organism (violation of its synthesis negatively affects health).
V atmospheric air at high temperatures, tungsten is rapidly oxidized, forming a characteristic white bloom on the inner surface of the lamp when it loses its tightness. For this reason, the tungsten filament is placed in a sealed bulb, from which air is evacuated during the lamp manufacturing process. Also, there are, even more often, gas-filled lamps: in them, the bulb is filled with an inert gas - usually argon. The increased pressure in the bulb of gas-filled lamps reduces the rate of evaporation of the tungsten filament. This not only extends the life of the lamp, but also increases the temperature of the incandescent body. Thus, the luminous Efficiency increases, and the radiation spectrum approaches white. Inner surface The bulb of a gas-filled lamp darkens more slowly when the filament material is sprayed during operation, as in an evacuated lamp. Retro bulbs are usually made with vacuum bulbs, but some manufacturers make them gas-filled.
Design
Incandescent lamp design. In the diagram: 1 - flask; 2 - flask cavity; 3 - thread (heating body); 4, 5 - electrodes; 6 - thread holder hooks; 7 - lamp leg; 8 - fuse; 9 - base case; 10 - base insulator (glass); 11 - contact of the bottom of the base.
The designs of incandescent lamps are very diverse, but consumer differences are mainly power, the shape and size of the bulb and the type of cap.
In the design of general-purpose lamps, a fuse is provided - a link made of a ferronickel alloy, welded into the rupture of one of the current leads and located outside the lamp bulb - as a rule, in the leg. The purpose of the fuse is to prevent the destruction of the bulb if the filament breaks during operation.
Filament
The shapes of the incandescences are very diverse and depend on functional purpose lamps. The incandescent body of the first lamps was made of coal... V modern lamps applied almost exclusively spirals of tungsten. To reduce the size of the body, the incandescence is usually given the shape of a spiral. In the case of retro light bulbs, when artistic effect is important, the spiral is attached as required for artistic effect, for example, imitates the spiral in the historic Edison bulbs. In the case of conventional light bulbs, the spiral is often hexagonal in order to ensure a uniform glow.
Plinth
Base / plinth shape with carving of a conventional incandescent lamp was offered By Joseph Wilson Swan or, according to other sources, by Lewis Howard Latimer - in the Edison firm. The plinth sizes are standardized. For household lamps, the most common Edison plinths E14, E27 and E40 (number indicates outside diameter in mm).
Different plinths are used in the USA and Canada (this is partly due to other voltage in networks- 110 V, therefore, other sizes of caps prevent accidental screwing of European lamps designed for a different voltage): E12 (candelabra), E17 (intermediate), E26 (standard or medium), E39 (mogul).
Interesting Facts
"Centenary lamp"
- In the United States, in one of the fire departments in the city of Livermore, California, there is a 60-watt lamp self made known as the "Centennial Lamp". It has been constantly burning for over 114 years, since 1901. The unusually high resource of the lamp was provided mainly by work on low power(4 watts), in deep sub-core, with very low efficiency. Lamp is included inGuinness book of records in 1972. Photos of this particular light bulb are often published as a "retro light bulb" ...
- In the USSR, after the implementation of Lenin's GOELRO plan, the incandescent lamp was nicknamed "Ilyich's light bulb." Nowadays, this is most often called a simple incandescent lamp hanging from the ceiling on an electric cord without a shade.
- A regular light bulb requires at least 7 metals to make.