What glows in an electric lamp. Incandescent lamp and its features. How to increase the life of an incandescent lamp

Incandescent lamp

Incandescent lamp- an electric light source in which an incandescent body (refractory conductor), placed in a transparent vessel evacuated or filled with an inert gas, is heated to a high temperature due to the flow of electric current through it, as a result of which it emits in a wide spectral range, including visible light . The filament body currently used is mainly a spiral of tungsten-based alloys.

Operating principle

The lamp uses the effect of heating the conductor (incandescent body) when electric current flows through it ( thermal effect of current). The temperature of the filament increases sharply after the current is turned on. A filament body emits electromagnetic thermal radiation in accordance with Planck's law. The Planck function has a maximum, the position of which on the wavelength scale depends on temperature. This maximum shifts with increasing temperature towards shorter wavelengths (Wien's displacement law). To obtain visible radiation, the temperature must be on the order of several thousand degrees. At a temperature of 5770 (the temperature of the surface of the Sun), the light matches the spectrum of the Sun. The lower the temperature, the lower the proportion of visible light, and the more “red” the radiation appears.

The incandescent lamp converts part of the electrical energy consumed into radiation, while part is lost as a result of the processes of heat conduction and convection. Only a small fraction of the radiation lies in the region of visible light, the main share comes from infrared radiation. To increase the efficiency of the lamp and obtain the most “white” light, it is necessary to increase the temperature of the filament, which in turn is limited by the properties of the filament material - the melting point. A temperature of 5771 K is unattainable, because at this temperature any known material melts, collapses and ceases to conduct electric current. Modern incandescent lamps use materials with maximum melting points - tungsten (3410 °C) and, very rarely, osmium (3045 °C).

To assess this quality of light, color temperature is used. At temperatures of 2200-3000 K typical for incandescent lamps, a yellowish light is emitted, different from daylight. In the evening, “warm” (< 3500 K) свет более комфортен и меньше подавляет естественную выработку мелатонина , важного для регуляции суточных циклов организма и нарушение его синтеза негативно сказывается на здоровье.

In ordinary air at such temperatures, tungsten would instantly turn into oxide. For this reason, the filament body is placed in a flask, from which air is pumped out during the manufacturing process of the lamp. The first ones were made using vacuum; Currently, only low-power lamps (for general purpose lamps - up to 25 W) are manufactured in an evacuated flask. The bulbs of more powerful lamps are filled with an inert gas (nitrogen, argon or krypton). The increased pressure in the bulb of gas-filled lamps sharply reduces the rate of evaporation of tungsten, due to which not only the service life of the lamp increases, but it is also possible to increase the temperature of the incandescent body, which allows increasing efficiency and bringing the emission spectrum closer to white. The bulb of a gas-filled lamp does not darken as quickly due to the deposition of filament body material as in a vacuum lamp.

Design

Design of a modern lamp. In the diagram: 1 - flask; 2 - flask cavity (vacuumed or filled with gas); 3 - filament body; 4, 5 - electrodes (current inputs); 6 - hooks-holders of the filament body; 7 - lamp leg; 8 - external link of current lead, fuse; 9 - base body; 10 - base insulator (glass); 11 - contact of the bottom of the base.

The designs of incandescent lamps are very diverse and depend on the purpose. However, the common elements are the filament body, bulb and current leads. Depending on the characteristics of a particular type of lamp, filament holders of various designs can be used; lamps can be made baseless or with different types of bases, have an additional external bulb and other additional structural elements.

In the design of general-purpose lamps, a fuse is provided - a link made of a ferronickel alloy, welded into the gap of one of the current leads and located outside the lamp bulb - usually in the leg. The purpose of the fuse is to prevent destruction of the bulb when the filament breaks during operation. The fact is that in this case, an electric arc occurs in the rupture zone, which melts the remaining filament; drops of molten metal can destroy the glass of the flask and cause a fire. The fuse is designed in such a way that when the arc is ignited, it is destroyed under the influence of an arc current significantly exceeding the rated current of the lamp. The ferronickel link is located in a cavity where the pressure is equal to atmospheric pressure, and therefore the arc easily goes out. Due to their low effectiveness, their use has now been abandoned.

Flask

The bulb protects the filament body from exposure to atmospheric gases. The dimensions of the bulb are determined by the rate of deposition of the filament body material.

Gas environment

The bulbs of the first lamps were evacuated. Most modern lamps are filled with chemically inert gases (except for low-power lamps, which are still made vacuum). Heat losses arising due to thermal conductivity are reduced by choosing a gas with a large molar mass. Mixtures of nitrogen N2 with argon Ar are the most common due to their low cost; pure dried argon is also used, less often krypton Kr or xenon Xe (molar masses: N2 - 28.0134 / mol; Ar: 39.948 g / mol; Kr - 83.798 g/mol; Xe - 131.293 g/mol).

Halogen lamp

The filament body of the first lamps was made of coal (sublimation temperature 3559 °C). Modern lamps use almost exclusively filaments made of tungsten, sometimes an osmium-tungsten alloy. To reduce the size of the filament body, it is usually given the shape of a spiral; sometimes the spiral is subjected to repeated or even tertiary spiralization, obtaining a bispiral or trispiral, respectively. The efficiency of such lamps is higher due to reduced heat loss due to convection (the thickness of the Langmuir layer decreases).

Electrical parameters

Lamps are manufactured for various operating voltages. The current strength is determined by Ohm's law ( I=U/R) and power according to the formula P=UI, or P=U²/R. Since metals have low resistivity, a long and thin wire is needed to achieve such resistance. The wire thickness in conventional lamps is 40-50 microns.

Since the filament is at room temperature when turned on, its resistance is an order of magnitude less than the operating resistance. Therefore, when turned on, a very large current flows (ten to fourteen times the operating current). As the filament heats up, its resistance increases and the current decreases. Unlike modern lamps, early incandescent lamps with carbon filaments worked on the opposite principle when turned on - when heated, their resistance decreased and the glow slowly increased. The increasing resistance characteristic of the filament (as the current increases, the resistance increases) allows the use of an incandescent lamp as a primitive current stabilizer. In this case, the lamp is connected in series to the stabilized circuit, and the average current value is selected so that the lamp operates at full intensity.

In flashing lamps, a bimetallic switch is built in series with the filament. Due to this, such lamps independently operate in flickering mode.

Base

In the USA and Canada, different sockets are used (this is partly due to a different voltage in the networks - 110 V, so different sizes of sockets prevent accidental screwing in of European lamps designed for a different voltage): E12 (candelabra), E17 (intermediate), E26 (standard or medium ), E39 (mogul). Also, similar to Europe, there are bases without threads.

Nomenclature

According to their functional purpose and design features, incandescent lamps are divided into:

general purpose lamps(until the mid-1970s, the term “normal lighting lamps” was used). The most widespread group of incandescent lamps intended for general, local and decorative lighting. Since 2008, due to the adoption by a number of states of legislative measures aimed at reducing production and limiting the use of incandescent lamps for the purpose of energy saving, their production began to decline;
decorative lamps, produced in shaped flasks. The most common are candle-shaped flasks with a diameter of approx. 35 mm and spherical with a diameter of about 45 mm;
local lighting lamps, structurally similar to general-purpose lamps, but designed for low (safe) operating voltage - 12, 24 or 36 (42) V. Area of application - hand-held (portable) lamps, as well as local lighting lamps in industrial premises (on machines, workbenches and etc., where accidental lamp breakage is possible);
illumination lamps, produced in painted flasks. Purpose - illumination installations of various types. As a rule, lamps of this type have low power (10-25 W). Flasks are usually colored by applying a layer of inorganic pigment to their inner surface. Less commonly used are lamps with bulbs painted on the outside with colored varnishes (colored tsaponlac), their disadvantage is the rapid fading of the pigment and shedding of the varnish film due to mechanical stress;
mirror incandescent lamps have a specially shaped flask, part of which is covered with a reflective layer (a thin film of thermally sprayed aluminum). The purpose of mirroring is the spatial redistribution of the light flux of the lamp for the purpose of its most effective use within a given solid angle. The main purpose of mirror LNs is localized local illumination;
warning lights used in various lighting devices (means of visual display of information). These are low power lamps designed to last a long time. Today they are being replaced by LEDs;
transport lamps- an extremely wide group of lamps designed to work on various vehicles (cars, motorcycles and tractors, airplanes and helicopters, locomotives and carriages of railways and subways, river and sea vessels). Characteristic features: high mechanical strength, vibration resistance, the use of special sockets that allow you to quickly replace lamps in cramped conditions and, at the same time, prevent the lamps from spontaneously falling out of the sockets. Designed for power supply from the on-board electrical network of vehicles (6-220 V);
spotlight lamps usually have high power (up to 10 kW; previously lamps up to 50 kW were produced) and high luminous efficiency. They are used in lighting devices for various purposes (lighting and signaling). The filament spiral of such a lamp is usually laid out more compactly in the bulb due to a special design and suspension for better focusing;
lamps for optical instruments, which include those mass-produced until the end of the 20th century. lamps for film projection equipment have compactly laid spirals, many are placed in specially shaped flasks. Used in various devices (measuring instruments, medical equipment, etc.);

Special lamps

Incandescent switch lamp (24V 35mA)

History of invention

Lodygin's lamp

Thomas Edison's lamp with a carbon fiber filament.

In 1809, the Englishman Delarue built the first incandescent lamp (with a platinum filament).
In 1838, the Belgian Jobard invents the carbon incandescent lamp.
In 1854, the German Heinrich Goebel developed the first “modern” lamp: a charred bamboo thread in an evacuated vessel. Over the next 5 years, he developed what many call the first practical lamp.
In 1860, the English chemist and physicist Joseph Wilson Swan demonstrated the first results and received a patent, but difficulties in obtaining a vacuum led to the fact that Swan's lamp did not work for long and was ineffective.
On July 11, 1874, Russian engineer Alexander Nikolaevich Lodygin received patent number 1619 for a filament lamp. He used a carbon rod placed in an evacuated vessel as a filament.
In 1875, V.F. Didrikhson improved Lodygin's lamp by pumping air out of it and using several hairs in the lamp (if one of them burned out, the next one turned on automatically).
English inventor Joseph Wilson Swan received a British patent for a carbon fiber lamp in 1878. In his lamps, the fiber was in a rarefied oxygen atmosphere, which made it possible to obtain very bright light.
In the second half of the 1870s, the American inventor Thomas Edison carried out research work in which he tried various metals as threads. In 1879 he patented a lamp with a platinum filament. In 1880, he returned to carbon fiber and created a lamp with a lifetime of 40 hours. At the same time, Edison invented the household rotary switch. Despite such a short lifespan, its lamps are replacing the gas lighting used until then.
In the 1890s, A. N. Lodygin invents several types of lamps with filaments made of refractory metals. Lodygin proposed using tungsten filaments in lamps (this is what is used in all modern lamps) and molybdenum and twisting the filament in the shape of a spiral. He made the first attempts to pump air out of lamps, which preserved the filament from oxidation and increased their service life many times over. The first American commercial lamp with a tungsten filament was subsequently produced according to Lodygin's patent. He also manufactured gas-filled lamps (with carbon filament and nitrogen filling).
Since the late 1890s, lamps with incandescent filaments made of magnesium oxide, thorium, zirconium and yttrium (Nernst lamp) or filaments of metal osmium (Auer lamp) and tantalum (Bolton and Feuerlein lamp) appeared.
In 1904, Hungarians Dr. Sandor Just and Franjo Hanaman received patent No. 34541 for the use of tungsten filament in lamps. The first such lamps were produced in Hungary, entering the market through the Hungarian company Tungsram in 1905.
In 1906, Lodygin sold a patent for a tungsten filament to General Electric. In the same 1906, in the USA, he built and put into operation a plant for the electrochemical production of tungsten, chromium, and titanium. Due to the high cost of tungsten, the patent finds only limited use.
In 1910, William David Coolidge invented an improved method for producing tungsten filament. Subsequently, the tungsten filament displaces all other types of filaments.
The remaining problem with the rapid evaporation of the filament in a vacuum was solved by an American scientist, a famous specialist in the field of vacuum technology, Irving Langmuir, who, working since 1909 at General Electric, introduced into production the filling of lamp bulbs with inert, or more precisely, heavy noble gases (in in particular - argon), which significantly increased their operating time and increased light output.

Efficiency and durability

Durability and brightness depending on operating voltage

Almost all the energy supplied to the lamp is converted into radiation. Losses due to thermal conductivity and convection are small. However, only a small range of wavelengths of this radiation is accessible to the human eye. The bulk of the radiation lies in the invisible infrared range and is perceived as heat. The efficiency of incandescent lamps reaches its maximum value of 15% at a temperature of about 3400. At practically achievable temperatures of 2700 (regular 60 W lamp), the efficiency is 5%.

As the temperature increases, the efficiency of an incandescent lamp increases, but at the same time its durability decreases significantly. At a filament temperature of 2700, the lamp life is approximately 1000 hours, at 3400 only a few hours. As shown in the figure on the right, when the voltage increases by 20%, the brightness doubles. At the same time, the lifetime is reduced by 95%.

Reducing the supply voltage, although it reduces efficiency, but increases durability. So, lowering the voltage by half (for example, when connected in series) reduces the efficiency by about 4-5 times, but increases the lifetime by almost a thousand times. This effect is often used when it is necessary to provide reliable emergency lighting without special brightness requirements, for example, on staircase landings. Often for this purpose, when powered by alternating current, the lamp is connected in series with a diode, due to which current flows into the lamp only for half the period.

Since the cost of electricity consumed during the service life of an incandescent lamp is tens of times higher than the cost of the lamp itself, there is an optimal voltage at which the cost of the luminous flux is minimal. The optimal voltage is slightly higher than the nominal voltage, so methods for increasing durability by lowering the supply voltage are absolutely unprofitable from an economic point of view.

The limited lifetime of an incandescent lamp is due to a lesser extent to the evaporation of the filament material during operation, and to a greater extent to the inhomogeneities that arise in the filament. Uneven evaporation of the filament material leads to the appearance of thinned areas with increased electrical resistance, which in turn leads to even greater heating and evaporation of the material in such places. When one of these constrictions becomes so thin that the filament material at that point melts or completely evaporates, the current is interrupted and the lamp fails.

The greatest wear on the filament occurs when voltage is suddenly applied to the lamp, so its service life can be significantly increased by using various types of soft-start devices.

A tungsten filament has a cold resistivity that is only 2 times higher than that of aluminum. When a lamp burns out, it often happens that the copper wires that connect the base contacts to the spiral holders burn out. Thus, a regular 60 W lamp consumes over 700 W when switched on, and a 100 W lamp consumes more than a kilowatt. As the coil warms up, its resistance increases, and the power drops to its nominal value.

To smooth out peak power, thermistors with a strongly decreasing resistance as they warm up, reactive ballast in the form of capacitance or inductance, and dimmers (automatic or manual) can be used. The voltage on the lamp increases as the coil warms up and can be used to automatically bypass the ballast. Without turning off the ballast, the lamp can lose from 5 to 20% of power, which can also be beneficial for increasing the resource.

Low-voltage incandescent lamps with the same power have a longer life and light output due to the larger cross-section of the incandescent body. Therefore, in multi-lamp lamps (chandeliers), it is advisable to use sequential switching of lamps at a lower voltage instead of parallel switching of lamps at mains voltage. For example, instead of six 220V 60W lamps connected in parallel, use six 36V 60W lamps connected in series, that is, replace six thin spirals with one thick one.

Type	Relative luminous efficiency	Luminous Efficacy (Lumen/Watt)
Incandescent lamp 40 W	1,9 %	12,6
Incandescent lamp 60 W	2,1 %	14,5
Incandescent lamp 100 W	2,6 %	17,5
Halogen lamps	2,3 %	16
Halogen lamps (with quartz glass)	3,5 %	24
High temperature incandescent lamp	5,1 %	35
Absolute black body at 4000 K	7,0 %	47,5
Absolute blackbody at 7000 K	14 %	95
Perfect white light source	35,5 %	242,5
Ideal monochromatic 555 nm (green) source	100 %	683

Below is an approximate ratio of power and luminous flux for conventional transparent incandescent lamps in the shape of a “pear”, popular in Russia, base E27, 220V.

Types of incandescent lamps

Incandescent lamps are divided into (arranged in order of increasing efficiency):

Vacuum (the simplest)
Argon (nitrogen-argon)
Krypton (approximately +10% brightness from argon)
Xenon (2 times brighter than argon)
Halogen (filler I or Br, 2.5 times brighter than argon, long service life, do not like underheating, since the halogen cycle does not work)
Halogen with two flasks (more efficient halogen cycle due to better heating of the inner flask)
Xenon-halogen (Xe + I or Br filler, the most effective filler, up to 3 times brighter than argon)
Xenon-halogen with an IR radiation reflector (since most of the lamp radiation is in the IR range, the reflection of IR radiation into the lamp significantly increases the efficiency, produced for hunting flashlights)
Filament with a coating that converts IR radiation into the visible range. Development of lamps with high-temperature phosphor is underway, which emits a visible spectrum when heated.

Advantages and disadvantages of incandescent lamps

Advantages:

well-established mass production
low cost
small sizes
lack of ballasts
insensitivity to ionizing radiation
purely active electrical resistance (unity power factor)
quick access to working mode
low sensitivity to power failures and voltage surges
absence of toxic components and, as a result, no need for collection and disposal infrastructure
ability to work on any type of current
insensitive to voltage polarity
the ability to manufacture lamps for a wide variety of voltages (from fractions of a volt to hundreds of volts)
no flickering when operating on alternating current (important in enterprises).
no buzzing when running on alternating current
continuous emission spectrum
pleasant and familiar spectrum
resistance to electromagnetic pulse
Possibility of using brightness controls
not afraid of low and high ambient temperatures, resistant to condensation

Flaws:

Import, procurement and production restrictions

Due to the need to save electricity and reduce carbon dioxide emissions into the atmosphere, many countries have introduced or are planning to introduce a ban on the production, purchase and import of incandescent lamps in order to force their replacement with energy-saving (compact fluorescent, LED, induction, etc.) lamps.

In Russia

According to some sources, in 1924, an agreement was reached between the cartel participants to limit the life of incandescent lamps to 1000 hours. At the same time, all lamp manufacturers belonging to the cartel were required to maintain strict technical documentation to comply with measures to prevent lamp life cycles from exceeding 1000 hours.

In addition, the cartel developed the current Edison base standards.

Notes

White LED lamps suppress melatonin production - Gazeta.Ru | The science
Buy Tools, Lighting, Electrical and DataComm Supplies at GoodMart.com
Photo lamp // Photocinema technology: Encyclopedia / Chief editor E. A. Iofis. - M.: Soviet Encyclopedia, 1981.
E. M. Goldovsky. Soviet film technology. Publishing house of the USSR Academy of Sciences, Moscow-Leningrad. 1950, p. 61
History of the invention and development of electric lighting
David Charlet. King of Invention Thomas Alva Edison
Electrical Engineering Encyclopedia. History of the invention and development of electric lighting
A. de Ladyguine, U.S. Patent 575,002 "Illuminant for Incandescent Lamps". Application on January 4, 1893 .
G.S. Landsberg. Elementary textbook of physics (Russian). Archived from the original on June 1, 2012. Retrieved April 15, 2011.
en:Incandescent light bulb
[Incandescent lamp]- article from the Small Encyclopedic Dictionary of Brockhaus and Efron
The History of Tungsram (PDF). Archived(English)
Ganz and Tungsram - the 20th century (English). (inaccessible link - story) Retrieved October 4, 2009.
A. D. Smirnov, K. M. Antipov. Energy engineer's reference book. Moscow, "Energoatomizdat", 1987.
Keefe, T.J. The Nature of Light (2007). Archived from the original on June 1, 2012. Retrieved November 5, 2007.
Klipstein, Donald L. The Great Internet Light Bulb Book, Part I (1996). Archived from the original on June 1, 2012. Retrieved April 16, 2006.
Black body visible spectrum
See luminosity function.
Incandescent lamps, characteristics. Archived from the original on June 1, 2012.
Taubkin S.I. Fire and explosion, features of their examination - M., 1999 p. 104
On September 1, the EU will stop selling 75-watt incandescent lamps.
The EU is restricting the sale of incandescent lamps from September 1, Europeans are unhappy. Interfax-Ukraine.
Medvedev proposed banning “Ilyich light bulbs”, Lenta.ru, 07/02/2009.
Federal Law of the Russian Federation of November 23, 2009 No. 261-FZ “On energy saving and increasing energy efficiency and on introducing amendments to certain legislative acts of the Russian Federation.”
Sabotage the veto , Lenta.ru, 01/28/2011.
"Lisma" has started producing a new series of incandescent lamps, State Unitary Enterprise RM "LISMA".
The need for invention is cunning: 95W incandescent lamps have appeared on sale, EnergoVOPROS.ru.

Currently, a 100 W incandescent lamp has the following design:

Hermetic pear-shaped glass flask. The air has been partially pumped out of it or replaced with inert gas. This is done to prevent the tungsten filament from burning out.
Inside the flask there is a leg to which two electrodes and several metal (molybdenum) holders are attached, which support the tungsten filament, preventing it from sagging and breaking under its own weight during heating.
The narrow part of the pear-shaped bulb is fixed in a metal base housing, which has a spiral thread for screwing into the plug socket. The threaded part is one contact, one electrode is soldered to it.
The second electrode is soldered to the contact on the bottom of the base. It has an annular seal around it from the threaded body.

Depending on the special operating conditions, some structural elements may be absent (for example, a base or holders), modified (for example, a base), or supplemented with other parts (an additional bulb). But parts such as filament, bulb and electrodes are the main parts.

The operating principle of an electric incandescent lamp

The glow of an electric incandescent lamp is caused by the heating of a tungsten filament through which an electric current passes. The choice in favor of tungsten in the manufacture of the luminescent body was made for the reason that, of many refractory conductive materials, it is the least expensive. But sometimes the filament of electric lamps is made of other metals: osmium and rhenium.
The power of the lamp depends on the size of the filament used. That is, it depends on the length and thickness of the wire. So a 100 W incandescent lamp will have a longer filament than a 60 W incandescent lamp.

Some features and purposes of the structural elements of a tungsten lamp

Each part in an electric lamp has its own purpose and performs its functions:

Flask. It is made of glass, a fairly cheap material that meets the basic requirements:
– high transparency allows light energy to pass through and absorb it to a minimum, avoiding additional heating (this factor is of paramount importance for lighting devices);
– heat resistance makes it possible to withstand high temperatures due to heating from a hot filament (for example, in a 100 W lamp the bulb heats up to 290 ° C, 60 W - 200 ° C; 200 W - 330 ° C; 25 W - 100 ° C, 40 W - 145°C);
– hardness allows it to withstand external pressure when pumping out air, and not collapse when screwed in.
Filling the flask. A highly rarefied environment allows minimizing heat transfer from the hot filament to the lamp parts, but enhances the evaporation of particles of the hot body. Filling with an inert gas (argon, xenon, nitrogen, krypton) eliminates strong evaporation of tungsten from the coil, prevents the filament from igniting and minimizes heat transfer. The use of halogens allows the evaporated tungsten to return back to the helical filament.
Spiral. It is made of tungsten, which can withstand 3400°C, rhenium – 3400°C, osmium – 3000°C. Sometimes, instead of a spiral filament, a ribbon or a body of a different shape is used in the lamp. The wire used has a round cross-section; to reduce size and energy loss for heat transfer, it is twisted into a double or triple helix.
Holder hooks are made of molybdenum. They do not allow the spiral, which has increased due to heating during operation, to sag much. Their number depends on the length of the wire, that is, on the power of the lamp. For example, a 100 W lamp will have 2 - 3 holders. Lower wattage incandescent lamps may not have holders.
Base made of metal with external thread. It performs several functions:
— connects several parts (flask, electrodes and central contact);
— serves for fastening in a plug socket using a thread;
- is one contact.

There are several types and shapes of bases depending on the purpose of the lighting fixture. There are designs that do not have a base, but with the same operating principle of an incandescent lamp. The most common types of base are E27, E14 and E40.

Here are some types of sockets used for different types of lamps:

In addition to different types of base, there are also different types of flasks.

In addition to the listed structural details, incandescent lamps may also have some additional elements: bimetallic switches, reflectors, bases without threads, various coatings, etc.

The history of the creation and improvement of the incandescent lamp design

Over its more than 100-year history of existence of an incandescent lamp with a tungsten filament, the operating principle and basic design elements have undergone almost no changes.
It all started in 1840, when a lamp was created that used the incandescent principle of a platinum spiral for lighting.
1854 – the first practical lamp. A vessel with evacuated air and a charred bamboo thread were used.
1874 - a carbon rod placed in a vacuum vessel is used as a filament body.
1875 - a lamp with several rods that glow one after another if the previous one burns out.
1876 - the use of a kaolin filament, which did not require pumping out air from the vessel.
1878 - the use of carbon fiber in a rarefied oxygen atmosphere. This allowed for bright lighting.
1880 - a carbon fiber lamp was created with a glow time of up to 40 hours.
1890 - the use of spiral threads made of refractory metals (magnesium oxide, thorium, zirconium, yttrium, metallic osmium, tantalum) and filling the flasks with nitrogen.
1904 – production of lamps with a tungsten spiral.
1909 – filling of flasks with argon.
More than 100 years have passed since then. The principle of operation, the materials of the parts, and the filling of the flask have remained virtually unchanged. Only the quality of materials used in the production of lamps, technical characteristics and small additions have undergone evolution.

Advantages and disadvantages of incandescent lamps over other artificial light sources

Created for lighting. Many of them were invented in the last 20 - 30 years using high technology, but a regular incandescent lamp still has a number of advantages or a set of characteristics that are more optimal for practical use:

Cheap in production.
Insensitive to voltage changes.
Fast ignition.
No flicker. This factor is very relevant when using alternating current with a frequency of 50 Hz.
Possibility of adjusting the brightness of the light source.
Constant spectrum of light radiation, close to natural.
Sharpness of shadows, as in sunlight. Which is also common for humans.
Possibility of operation in conditions of high and low temperatures.
The ability to produce lamps of various powers (from several W to several kW) and designed for different voltages (from several Volts to several kV).
Easy disposal due to the absence of toxic substances.
Possibility of using any type of current with any polarity.
Operation without additional starting devices.
Quiet operation.
Does not create radio interference.

Along with such a large list of positive factors, incandescent lamps also have a number of significant disadvantages:

The main negative factor is the very low efficiency. It reaches only 15% for a 100 W lamp; for a 60 W device this figure is only 5%. One way to increase efficiency is to increase the filament temperature, but this sharply reduces the service life of the tungsten filament.
Short service life.
High surface temperature of the bulb, which can reach 300°C for a 100-Watt lamp. This poses a threat to the life and health of living beings and poses a fire hazard.
Sensitivity to shake and vibration.
Use of heat-resistant fittings and insulation of current-carrying wires.
High power consumption (5-10 times rated) during startup.

Despite the presence of significant disadvantages, the incandescent electric lamp is the only lighting device. Low efficiency is compensated by low cost of production. Therefore, in the next 10–20 years it will be a highly sought-after product.

An incandescent lamp is an electric lighting device whose operating principle is determined by heating a filament of refractory metal to high temperatures. The thermal effect of current has been known for a long time (1800). Over time, it causes intense heat (above 500 degrees Celsius), causing the filament to glow. In the country, little things are named after Ilyich; in fact, advanced historians are powerless to give a definitive answer as to who should be called the inventor of the incandescent lamp.

Construction of incandescent lamps

Let's study the structure of the device:

History of incandescent lamps

Spirals were not immediately made from tungsten. Graphite, paper, and bamboo were used. Many people followed a parallel path, creating incandescent lamps.

We are powerless to give a list of 22 names of scientists called by foreign writers as the authors of the invention. It is wrong to attribute merit to Edison and Lodygin. Today, incandescent lamps are far from perfect and are rapidly losing their marketing appeal. Exceeding the amplitude of the supply voltage by 10% (half of the way - 5% - the Russian Federation did in 2003, raising the voltage) of the nominal value reduces the service life by four times. Reducing the parameter naturally reduces the output of the luminous flux: 40% is lost with an equivalent relative change in the characteristics of the supply network downward.

The Pioneers are much worse off. Joseph Swan was desperate to achieve sufficient rarefaction of air in the bulb of an incandescent lamp. The (mercury) pumps of that time were unable to complete the task. The thread burned using the oxygen preserved inside.

The purpose of incandescent lamps is to bring the spirals to the point of heating, the body begins to glow. Difficulties were added by the absence of high-resistance alloys in the mid-19th century - the quota for converting electric current was formed by the increased resistance of the conductive material.

The efforts of pundits were limited to the following areas:

Choice of thread material. The criteria were both high resistance and combustion resistance. Bamboo fibers, which are an insulator, were coated with a thin layer of conductive graphite. The small area of the conductive layer of coal increased the resistance, giving the desired result.
However, the wood base quickly ignited. We consider the second direction to be attempts to create a complete vacuum. Oxygen has been known since the end of the 18th century; scientists quickly proved that the element participates in combustion. In 1781, Henry Cavendish determined the composition of the air, starting to develop incandescent lamps, the servants of science knew: the earth's atmosphere destroys heated bodies.
It is important to convey the tension of the thread. Work was underway with the goal of creating detachable, contact parts of the circuit. It is clear that a thin layer of coal is equipped with a large resistance, how to supply electricity? It’s hard to believe that, trying to achieve acceptable results, they used valuable metals: platinum, silver. Obtaining acceptable conductivity. Using expensive methods, it was possible to avoid heating the external circuit and contacts; the filament became heated.
Separately, we note the thread of the Edison base, which is still used today (E27). A successful idea that formed the basis of quickly replaceable incandescent light bulbs. Other methods of creating contact, such as soldering, are of little use. The connection can disintegrate when heated by the action of current.

Glassblowers of the 19th century reached professional heights; flasks were easily made. Otto von Guericke, when constructing a static electricity generator, recommended filling a spherical flask with sulfur. The material will harden and break the glass. The result was an ideal ball; when rubbed, it collected a charge, giving it to a steel rod passing through the center of the structure.

Industry pioneers

You can read: the idea of subordinating electricity for lighting purposes was first realized by Sir Humphry Davy. Soon after the creation of the voltaic column, the scientist experimented with metals with all his might. I chose noble platinum for its high melting point - other materials were quickly oxidized by air. They simply burned out. The light source turned out to be dim, giving the basis for hundreds of subsequent developments, showing the direction of movement for those who wanted to get the final result: illumination, with the help of electricity.

It happened in 1802, the scientist was 24 years old, later (1806) Humphry Davy presented to the public a fully functional discharge lighting device, in the design of which two coal rods played a leading role. The short life of such a brilliant luminary in the firmament of science, who gave the world an idea of chlorine, iodine, and a number of alkali metals, should be attributed to constant experiments. Lethal experiments on inhalation of carbon monoxide, work with nitric oxide (a powerful toxic substance). The authors saluted the brilliant exploits that shortened the scientist’s life.

Humphrey abandoned it, cutting out a whole decade of research into lighting devices, always busy. Today Davy is called the father of electrolysis. The Felling Colliery tragedy of 1812 left a deep imprint, darkening the hearts of many. Sir Humphry Davy joined the ranks of those involved in the development of a safe light source that would protect miners. Electricity was scarce and there were no powerful reliable sources of energy. To prevent firedamp from exploding at times, various measures were used, such as a metal mesh diffuser that prevented the spread of flame.

Sir Humphry Davy was far ahead of his time. About 70 years ago. The end of the 19th century brought forth new designs like an avalanche, designed to snatch humanity out of eternal darkness, thanks to the use of electricity. Davy was one of the first to note the dependence of the resistance of materials on temperature, allowing Georg Ohm to later obtain. Half a century later, the discovery formed the basis for the creation of the first electronic thermometer by Carl Wilhelm Siemens.

On October 6, 1835, James Bowman Lindsay demonstrated an incandescent light bulb surrounded by a glass bulb to protect it from the atmosphere. As the inventor put it: one could read a book by dispelling darkness at a distance of one and a half feet from such a source. James Bowman, according to generally accepted sources, is the author of the idea of protecting the filament with a glass bulb. Is it true?

We are inclined to say that this is where world history gets a little confused. The first sketch of such a device dates back to 1820. For some reason attributed to Warren de la Roux. Who was... 5 years old. A lone researcher noticed the absurdity when he set the date... 1840. A kindergartener is powerless to make such a great invention. Moreover, James Bowman’s demonstrations were forgotten in a hurry. Many historical books (one from 1961, by Lewis) interpreted the picture that came from out of nowhere in this way. Apparently, the author was mistaken; another source, 1986 by Joseph Stoer, attributes the invention to Augustus Arthur de la Riva (born 1801). Much better suited to explain James Bowman's demonstrations fifteen years later.

It went unnoticed by the Russian-language domain. English sources interpret the problem as follows: the names de la Roux and de la Rive are clearly mixed up and may concern at least four individuals. Physicists Warren de la Roux and Augustus Arthur de la Rive are mentioned; the first attended kindergarten in 1820, figuratively speaking. The fathers of the men mentioned can clarify the story: Thomas de la Roux (1793 - 1866), Charles Gaspard de la Rive (1770 - 1834). An unknown gentleman (lady) conducted a whole study, convincingly proved that the reference to the de la Roux surname is untenable, citing a mountain of scientific literature from the early 20th to the end of the 19th century.

The unknown person took the trouble to look through Warren de la Roux's patents, and there were nine of them. There are no incandescent lamps of the described design. It is difficult to imagine Augustus Arthur de la Riva, who began publishing scientific works in 1822, inventing the glass flask. He visited England, the birthplace of the incandescent light bulb, and studied electricity. Those interested can write to the author of the article on the English-language site by email [email protected]. “Ezhkov” writes: he will be happy to take into account information related to the issue.

The true inventor of the incandescent light bulb

It is reliably known that in 1879 Edison patented (US Patent 223898) the first incandescent light bulb. Descendants recorded the event. Regarding earlier publications, the authorship is questionable. The commutator engine that gave the world the gift is unknown. Sir Humphry Davy refused to take out a patent for the invented safety lamp for the mine, making the invention publicly available. Such whims create considerable confusion. We are powerless to find out who was the first to come up with the idea of placing a filament inside a glass bulb, ensuring the functionality of the design that is used everywhere.

Incandescent lamps are going out of fashion

An incandescent lamp uses a secondary principle of light production. The thread reaches a high temperature. The efficiency of devices is low, most of the energy is wasted. Modern standards dictate the country to conserve energy. Discharge, LED light bulbs are in fashion. Humphry Davy, de la Roux, de la Rive, Edison, who had a hand and worked to pull humanity out of darkness, will forever remain in the memory.

Please note that Charles Gaspard de la Rive died in 1834. The following fall, the first public demonstration took place... Has anyone found the records of the deceased researcher? Time will resolve the question, for everything secret will be revealed. Readers noticed: an unknown force was pushing Davy to try to use the protective flask to help the miners. The scientist's heart turned out to be too big to see the obvious hint. The Englishman had the necessary information...

After the circuit is closed (for example, when a switch is pressed), electric current begins to pass through the filament, which, when it reaches a certain temperature, emits radiation visible to the human eye. When the temperature reaches 570 o C, a person is able to see a red glow emitted by the body in the dark, and the standard operating temperature of the filament in an incandescent lamp is in the range of 2000-2800 ° C. The lower the temperature of the incandescent body, the more “red” the radiation will look (more details about color rendition are written in the article). To better understand the principle of operation of a conventional light bulb, it is necessary to understand the design and required elements, which include the bulb, filament body and current leads.

A standard light bulb is pear-shaped and consists of the following parts:

Flask. Made from soda-lime silicate glass, it can be transparent, matte, milky, opal, mirror (reflective). If a light bulb is used without a shade in a small room, then pay attention to light bulbs with a frosted or milky bulb, since their luminous fluxes are 3% and 20%, respectively, less than the luminous flux of transparent lamps. Flasks can also be coated on the outside with decorative dyes, varnishes, and ceramics.
Buffer gas(bulb cavity). To prevent oxidation of the coil (the filament body), air is pumped out of the flask, creating a vacuum inside. However, today vacuum is used only in low-power light bulbs, and most modern models are filled with an inert gas, which increases the glow intensity. According to the composition of the gaseous medium, incandescent lamps can be divided into: vacuum, gas-filled (xenon, krypton, a mixture of nitrogen with argon, etc.), halogen.
filament body. Most often it is made of round wire, less often - from strip metal. The first models of light bulbs used a carbon filament, while modern ones used a spiral made of tungsten or an osmium-tungsten alloy.
Current inputs(lead wire).
Filament holders(molybdenum holders).
Leg(extension rod and lamp leg).
External link of current lead.
Fuse link(fuse)
Base housing.
Glass base insulator.
Base contact.

What are the types/types of incandescent lamps?

The classification of incandescent lamps is quite extensive, as it takes into account many characteristics.

By type of base The most common are threaded and pin. In everyday life, you can most often find a threaded Edison base, designated by the letter E, next to which its diameter is written in millimeters, for example, E10, E14, E27 and E40.

According to the shape of the flask incandescent light bulbs come in a variety of varieties, from standard pear-shaped to curly, twisted, etc. In some cases, the size and shape of the bulb (as well as the presence of reflective areas) are related to where the incandescent lamp is used, in other cases it is related to the decorative function.

Incandescent lamps: characteristics and markings

To know how to choose an incandescent lamp, you need to learn to read its markings, which are a combination of letters and numbers. The letter part of the marking indicates the properties and design of the product, for example:

B– double-spiral

BO– double-spiral with an opal flask filled with argon

BC– double-spiral, flask filled with krypton

DB– diffuse with matting inside the flask

IN– vacuum

G— gas-filled

ABOUT– with opal flask

M– with milk flask

Sh– spherical

Z– specular (ZK – concentrated light curve, ZSh – extended curve)

MO– used for local lighting

The numbers indicate the voltage range and power. Thus, the marking B 220..230 60 can be deciphered as follows: a 60W incandescent incandescent lamp, designed for a voltage range from 220 to 230 V.

What are the disadvantages/advantages of an incandescent lamp?

The advantages of incandescent light bulbs include:

low cost;
wide power range;
uninterrupted operation at low voltage (with reduced lighting intensity);
resistance to minor voltage drops (with a possible reduction in service life);
comfortable color temperature (warm);
Possibility of use in wet areas;
ease of operation.

The disadvantages include:

strong heating (creating a fire hazard);
short service life;
low light output (efficiency<4%)
dependence of light output on voltage;
risk of flask rupture;
fragility.

How to increase the life of an incandescent lamp?

As mentioned earlier, the service life of incandescent light bulbs expected by the manufacturer reaches an average of 750-1000 hours, but in practice they burn out much more often. This occurs due to the occurrence of cracks and destruction of the tungsten filament (due to overheating and evaporation). To extend the life of the lamp, you should first eliminate the possible causes of burnout.

Voltage range. For different incandescent lamps, manufacturers indicate not one voltage value, but a range: 125..135, 220..230, 230..240V, etc. If the voltage in your apartment circuit exceeds the specified values, the lamp will burn out faster, therefore, with a voltage of 230V, you cannot choose a lamp with parameters 215..220V. So, if the voltage is only 6% higher, the service life will be halved.
Vibrations. Under vibration conditions, the filament wastes its resource faster, so when using portable devices it is better to move with the light bulb turned off.
Cartridge. If you notice that light bulbs most often burn out in the same socket, then you should replace it or check the contacts. You should also place lamps of equal power in a chandelier with several sockets.
Voltage reduction. If you lower the network voltage by just 8%, the light bulb will last 3.5 times longer. To reduce it, you can connect a semiconductor diode in series with the lamp.

The longest-burning incandescent light bulb is called the "Hundred Year Lamp" and is located at a fire station in Livermore, California. Thanks to its operation at very low power (4 watts), a thick carbon filament (8 times thicker than conventional light bulbs of our time), and uninterrupted use without turning off and on, it has been working there since 1901.

How to connect an incandescent lamp via a diode

To extend the life of the light bulb (and at the same time save on electricity), you can connect it via a diode. When choosing a diode, you need to pay attention to such parameters as the maximum forward current (+ in the pulse) and the maximum reverse voltage. To make the task easier and not have to calculate all the parameters, here is a table:

To assemble the structure you will need:

1 working E27 light bulb
1 non-working E27 light bulb (or socket from it);
diode;
soldering iron

Build process. Solder the diode to the spot on the base of the working light bulb. Carefully separate the base from the burnt-out light bulb, make a hole in it and thread the second “leg” of the diode through it. We solder the lead-out end to the lead-out point, then solder both bases together.

An easier way: connect one end of the diode to the switch terminal, and the other to the wire that leads to the light bulb.

How does a diode extend the life of an incandescent light bulb?

In most cases, the filament burns out when power is applied (the switch is turned on) due to the cold coil heating up too quickly. The semiconductor diode reduces the current and allows the tungsten to heat up gradually, at a slower rate. The light bulb begins to flicker noticeably, as the current passes in half waves.

It turns out that a body heated by an electric current can not only emit heat, but also glow. The first light sources operated precisely on this principle. Let's look at how an incandescent lamp, the most widely used lighting device in the world, works. And, although over time it will have to be completely replaced by compact fluorescent (energy-saving) and LED light sources, humanity 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 mounted on supporting elements, the outermost of which serve 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 terminal.

Molybdenum holders hold the tungsten helix

Air has been 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. Additionally, this measure prevents oxidation of the filament. When making a lamp, air is pumped out through part of the bulb, which is then hidden by the base.

The principle of operation of an incandescent lamp is based on heating its filament by electric current to a temperature at which it begins to emit light into the surrounding space.

Incandescent lamps can be manufactured with a power from 15 to 750 W. Depending on the power, different types of threaded sockets are used: E10, E14, E27 or E40. For decorative, signal and backlight lamps, BA7S, BA9S, BA15S sockets are used. When installed, such products are stuck inside the cartridge and rotated 90 degrees.

In addition to the usual pear-shaped shape, decorative lamps are also produced in which the bulb is shaped like a candle, drop, cylinder, or ball.

A lamp with a bulb that does not have a coating glows with a yellowish light, the composition most reminiscent of sunlight. But when special coatings are applied to the inner surface of the glass, it can become matte, red, yellow, blue or green.

The design of a reflective incandescent lamp is of interest. A reflective layer is applied to part of its bulb. As a result, due to reflection from it, the light flux is redistributed in one direction.

Advantages of incandescent lamps

The most important advantage in favor of using incandescent light bulbs is the ease of their manufacture and, accordingly, the price. It’s impossible to think of a simpler lighting device.

Lamps are manufactured in a wide range of wattages and overall dimensions. All other modern light sources contain devices that convert the supply voltage to the value necessary for their operation. Although they manage to squeeze them into the standard overall dimensions of a 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 lamps have replaced conventional lamps as 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. And they work more successfully as part of Christmas tree garlands.

It is worth noting another advantage inherent in incandescent light bulbs - their luminescence spectrum is closest to that of the sun than that of 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 the radiation from other devices, especially luminescent ones, which use a regular inductor rather than a semiconductor circuit as a ballast. And electronics, especially cheap ones, do not always suppress ripple from the network properly. This also affects vision.

But not only health can be damaged by the pulsating nature of the operation of 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 operation of other electrical appliances in the network.

Disadvantages of incandescent lamps

A significant drawback of incandescent light bulbs, which shortens their service life, is its dependence on the value of the supply voltage. As the voltage increases, the filament wears out faster. Lamps are produced for different values of this parameter (up to 240 V), but at the nominal value they shine worse.

A decrease in voltage leads to a sharp change in the intensity of the glow. And vibrations have an even worse effect on the lighting device; with sudden fluctuations, the lamp can burn out.

But the worst thing is that the filament is designed to operate for a long time 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 current surge at the moment of ignition, leading to the evaporation of tungsten. The greater the number of switches, the shorter the lamp will last.

Devices for smooth starting or that allow you to adjust the brightness of the glow over a wide range help correct the situation.

The most important disadvantage of incandescent light bulbs is their low efficiency. The overwhelming majority 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.

Well, one more thing: the glass of the flask is easy to break. But unlike compact fluorescent lamps, which contain a small amount of mercury vapor inside, a broken incandescent lamp, apart from a possible cut, does not threaten the owner in any way.

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 current surge when turned on melts it at its thinnest point.

Halogen lamps filled with bromine or iodine vapor are designed to eliminate this drawback. When burned, evaporated tungsten combines with halogen. The resulting substance is not able to deposit on the walls of the flask or other relatively cold internal surfaces.

Near the filament, tungsten, under the influence of temperature, is removed from the connection and returned to its place.

The use of halogens solves another problem: the temperature of the spiral can be increased, increasing the luminous output and reducing the size of the lighting device. Therefore, at the same power, the dimensions of halogen lamps are smaller.