The filament bodies of modern incandescent lamps are made of. Types of electric lamps

Two bulbs from a Christmas garland are connected in series

Today, when the people are preparing to meet New Year, on the SamElektrik.ru blog, we are already thinking about Summer. More precisely, about summer, the first article of which is published today!

The article can be considered scientific and theoretical, but rather engineering and practical.
There is no doubt that the article may be of interest to engineers and technicians whose activities are related to the operation of such a simple and familiar device to all of us as an incandescent light bulb. And also - for everyone who is interested in physics.

I remind you that I already had an attempt to explore this issue on my blog - in my article ““

Despite the commonness of the light bulb, despite its “everyday life”, the features of its operation have what is commonly called “white spots”.

At the moment, the electrical parameters of an incandescent lamp cannot be calculated if the operating mode differs from the passport one (from the mode for which the light bulb is designed). The author proposes a physical model within which it is possible to obtain a number of formulas suitable for solving a wide range of practical engineering problems.

I express my gratitude to the owner of the resource for the kindly given the opportunity to publish this memoir.

Matrosov S.

incandescent lamp

This article is proposed to be understood as an expanded interpretation (or explanation) of the article "Kepler's law for an incandescent light bulb" - https://www.proza.ru/2016/09/19/1858

This article provides a formula that allows you to calculate the parameters of an incandescent lamp in arbitrary modes, including modes that differ from passport ones.

The formula for the dependence of voltage and power of a light bulb

This is the main formula of the article, the derivation of which will be given below. The formula looks like this:

For any incandescent lamp, there is a parameter that is stable over a wide range of electrical modes. This parameter is the ratio of the cube of voltage to the square of power.

The technique for using the formula is simple.

We take a light bulb, read on the bulb or on the base the parameters for which it is designed - voltage and power, calculate the constant, then insert any arbitrary voltage into the formula and calculate the power that will be released on the light bulb.

Knowing the power, it is easy to calculate the current.

Knowing the current, it is easy to calculate the resistance of the filament.

Let's take a look at issues related to proper operation formulas, as well as with those restrictions that are inevitable due to the fact that "absolute" formulas simply do not exist.

However, first a little "theory" ...

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Basic "theoretical" premises

The formula was obtained on the assumption that in the metal (of which the filament consists) current and resistance have a single physical essence.

In a simplified form, it can be argued something like this.

According to modern views, the current is an ordered movement of charge carriers. For metal it will be electrons.

It was assumed that the electrical resistance of the metal is determined by the CHAOTIC motion of the same electrons.

As the temperature of the filament increases, the chaotic motion of electrons increases, which ultimately leads to an increase in electrical resistance.

Again. Current and resistance in a filament are the same thing. The only difference is that current is an ordered movement under the influence of an electric field, and resistance is a chaotic movement of electrons.

A bit of "algebraic scholasticism"

Now that the “theory” is over (smiled), I will give algebraic calculations for the derivation of the “main” formula.

The canonical notation of Ohm's law looks like:

I*R=U

To align quantitative values, it is necessary to enter the appropriate coefficients of proportionality, for the current component - Kt and for the resistive component - Kp:

The most general considerations lead to the idea that these coefficients should be mutually reciprocal, which means:

In this case, multiplying in pairs the right and left sides (in the system of equations), we return to the original Ohm's law:

I*R=U

The final derivation of the formula

Let's take a closer look at the system of equations:

We square the first equation and multiply them in pairs.

On the left side we see the expression for the power, and also bearing in mind that the product of the coefficients is equal to one, we finally rewrite:

From here we get the expression for the current coefficient:

And for the resistive coefficient (they are mutually inverse):
where Rnom and Unom are the rated power and voltage marked on the base or on the lamp bulb.

It remains to substitute these values ​​of the coefficients in the "SPLIT" formula of Ohm's Law, and we will get the final expressions for current and resistance.

Multiplying the last relation by Ux, we get:

In order not to bother yourself with these squares, cubes and roots, it is enough to remember the simple dependence that follows from the last relation. Squaring the last relation, we get a clear and understandable formula:

For any light bulb with a tungsten filament, the ratio of the cube of voltage to the square of power is a CONSTANT value.

The relations obtained showed excellent agreement with practical results (measurements) in a wide range of voltage parameters and for very various types incandescent lamps, ranging from indoor, automotive and ending with bulbs for flashlights ...

Some general reasoning on the resistance of incandescent bulbs

Of course, for small voltage values ​​(when the applied voltage is SIGNIFICANTLY different from the nameplate), our formulas will “twist”.

For example, when calculating the resistance of a room incandescent bulb 95W, 230V, connected to a voltage source of 1 volt, the formula

gives a filament resistance value of 36.7171 ohms.

If we assume that we applied a voltage of 0.1 volts to the lamp, then design resistance thread will be 11.611 ohms ...

Intuition tells us that this is not at all the case, but rather not at all…

In the region of low voltages, the formula will stably “lower” the value of the calculated resistance compared to the actual one, and here's the thing...

In the concept under consideration, it is implicitly assumed that the chaotic motion of electrons “FREEZES” in the absence of an external applied voltage. However, it is obvious that the movement of electrons does not “freeze” even in the absence of an applied external voltage (if the lamp just lies on the table and is not turned on anywhere).

The chaotic motion of electrons has a THERMAL nature and is due to the NATURAL TEMPERATURE of the filament.

This moment is not taken into account by the formula and direct measurement of the thread resistance by the device will inevitably show the difference between the measured resistance value and the calculated one.

Radiation and efficiency of an incandescent light bulb

Before dealing with the question of the applicability of the formula for calculating “low voltage” modes, attention should be focused on one point.

A light bulb is an almost perfect converter of electrical power into radiant energy.

The fact that light bulb developers are stubbornly fighting to increase the efficiency of a light bulb does not affect this statement in any way. An incandescent lamp is an ideal converter of electrical power into radiation.

The fact is that developers strive to increase the output of LIGHT energy, and it is in this sense that they calculate the efficiency. The developer seeks to increase the coefficient of conversion of electrical power into LIGHT radiation, into radiation in the visible range.

This efficiency of the light bulb is really small. However, the light bulb radiates beautifully IN THE WHOLE spectrum and very much in the infrared range, where our eye does not see.

To calculate purely electrical parameters, it does not matter to us at all, IN WHAT range the light bulb emits. It is only important for us to remember that the light bulb ALWAYS radiates, if only some (even the smallest) voltage is applied to it. And it's important to remember that the input power is dissipated in the form of radiation.

How much electrical power is supplied to the lamp, it is SUCH power that will be dissipated in the form of radiation.

Nobody canceled the law of conservation of energy and nobody canceled the second law of thermodynamics either. So, how much has arrived - so much should go. And it will decrease precisely in the form of radiation, because there is simply NO WHERE to go to more energy - only in radiation. This is a very important circumstance.

Structurally, the filament is a thin tungsten wire with a diameter of about 50 microns and a length of about half a meter, coiled into a spiral of intricate configuration.

Vacuum in the flask eliminates the possibility of convection heat transfer - ONLY THROUGH RADIATION.

Of course, some part of the heat escapes through the antennae of the lamp on which the spiral is attached, but this is minuscule.

To visualize this smallness, we can draw an analogy.

I repeat, the tungsten filament itself is exactly the size of a hair from a first grader's pigtail, 50 cm long and 50 microns in diameter.

If you visually enlarge this hair ... it's like if we have wires with a diameter of 1 mm and a length of 10 meters! Common sense dictates that this wiring is NOT cooled by heat transfer at the edges. Yes, something will go away at the points of contact, but the main power will be dissipated along the entire length of the wiring.

For the case of a spiral located in a vacuum, all the power will go into the RADIATION and it doesn’t matter in what range of the spectrum…

An important experiment with measuring resistance with an ohmmeter

Any, even the smallest current WILL have a thermal effect on the wiring, HEATING it ...

By measuring the resistance of a light bulb with a tester, we ... pass a CURRENT through it. The current from the tester is small, but it IS. Therefore, when measuring the resistance of a thread, we HEAT the thread and, as a result, change the value of the parameter by the very fact of measurement.

Roughly speaking, the tester ALSO LIES. Tester shows NOT TRUE coil resistance value.

In order to verify this circumstance, you can do a simple experiment. It's available to anyone.

You can use the SAME tester to select two light bulbs with the same (close) values ​​of the “cold” resistance of the thread, and measure the resistance of TWO bulbs, first each separately, and then connected in series.

Repeated measurements show that the sum of the resistances measured separately DOES NOT COME WITH the total resistance of the series connection ...

We measure the resistance of light bulbs separately.

We then measure the series resistance.

And we STEADY observe that the sum of the resistances measured “single” turns out to be MORE than the total resistance of the bulbs connected in series.

The device is the same, the measurement range was not switched, so that methodological measurement errors are excluded.

And everything becomes clear.

The series resistance of the two coils REDUCE the current from the tester, and the filaments heat up less.

And when we measure the light bulbs separately, then the measurement current is greater and, accordingly, the readings of the device increase due to even a small, but INCREASE in the temperature of the filaments due to heating during the measurement process ...

Previously (a quarter of a century ago, when digital testers were still exotic), it was impossible to catch this difference with a pointer indicator. Now in any house there is a Chinese digital tester and anyone can do this simple experiment.

The difference in resistances is small, but the difference is OBVIOUS, which excludes even a hint of a possible incorrectness of the experiment.

I connected the light bulbs, connected the tester and photographed the results of such experiments. The photographs clearly show that the tester shows a reduced resistance of light bulbs connected in series.

In the photographs for household light bulbs 60 watts 220 volts, the sum of the resistances measured separately: 72.0 + 65.2 = 137.2 ohms.

However, by measuring the resistance in series, the instrument will “lower” the reading to 136.8 ohms!

A similar picture is observed for garland light bulbs:

Conclusion. The calculation formula shows the LOWER value of the resistance of the “cold” coil.

Tester measurement shows INCREASED cold coil resistance.

A natural thought arises - How scary to live !!! Who to believe?

Let's try to figure this out...

Radiation power in relation to the surrounding background

Let us estimate the radiation power of the lamp corresponding to the ambient background temperature.

It is known that the Stefan-Boltzmann constant σ = 5.670373 10 -8, then the radiation power per square meter

P \u003d σ ST 4

As an arbitrary estimated value, we will take a spiral diameter of 40 microns and a length of 50 cm. The temperature of normal conditions is 293K (20C). Substituting these data into the Stefan-Boltzmann formula, we obtain the radiation power at a temperature of 0.026258 watts.

For interest, we calculate the power for some various temperatures environment:

Minus 40 (233K) 0.0105 Watt

Minus 20 (253K) 0.0146 Watt

Zero (273K) 0.0198 Watts

Plus 20 (293K) 0.026258 Watt (normal conditions)

Plus 40 (313K) 0.0342 Watt

For curiosity, you can calculate the radiation of the lamp when the ambient temperature is 2300K:

P = 99.7 watts.

Which, in general, is in good agreement with the real state of affairs - a lamp designed for 100 watts heats up to a temperature of 2300K.

It can be stated with a high degree of certainty that this spiral geometry corresponds to a "hundred-watt" light bulb rated at 220 volts.

Now let's recalculate these power values ​​to the "reduced" voltage. As if the ambient temperature corresponded to Absolute Zero, and some voltage was applied to the lamp, heating the coil.

For recalculation, we use the resulting ratio that voltages and powers correspond to the powers of "three" and "two".

The table shows that the “current” power of the light bulb at a voltage of 0.902 ... Volt heats the coil to a temperature of 293K. Similarly, "current" power at a voltage of 1.0758 volts will heat the coil to a temperature of 313K (20 degrees higher).

Again, this is assuming that the ambient temperature is Absolute Zero.

Conclusion. A very small change in voltage has a significant effect on the temperature of the filament. We changed the voltage by some seventeen hundredths of a Volt (1.0758 - 0.902 \u003d 0.1738) and the temperature increased by 20 degrees.

These calculations are very conditional, but they can be used as ESTIMATED values.

The estimate is naturally very rough, because the Stefan-Boltzmann law describes the radiation of an “ideal” emitter - a blackbody (blackbody), and the spiral is very different from the blackbody, but, nevertheless, we got a very plausible “number” ...

From the Excel plate it can be seen that already at a voltage of 1 volt on the lamp, the temperature of the spiral will be 40 degrees Celsius. We put in more, there will be more.

A natural conclusion suggests itself that at a voltage of 10-15 volts, the thread will be quite hot, although this will not be visible visually.

To the eye, the thread will appear "BLACK" (cold) up to temperatures of 600 degrees (the beginning of radiation in the visible range).

Those who wish to “drive numbers” can do this on their own using the Stefan-Boltzmann formula.

The results will be conditional, due to the fact that (as mentioned above) the spiral has some albedo and does not correspond to the blackbody emitter, BUT (!) The temperature estimate will be quite reliable ...

I repeat - it is an EVALUATION. The thread begins to glow at about 20 volts.

In addition, I would like to draw attention to the spread of the parameters of the light bulbs.

In the photo with the tester, the small bulbs (garland) were selected and calibrated by me very carefully. For various measuring purposes and experiments. That is why they show the same resistance, which is called “bullet to bullet”.

Expressions for currents are equal. Small algebraic transformations. And the final square equation is obtained with respect to the unknown Us.

From the figure it is clear that Us is the voltage on the lamp.

From the Blog Administrator.

This article participates in the Summer 2018 Article Contest. Summing up (tentatively) - in June 2018. Subscribe to receive new articles and join the VK group, there is always more news than on the blog!

Incandescent lamps cannot contain air, nitrogen, or any other gases other than inert ones (argon, krypton, xenon). The fact is that the temperature of the spiral is more than 2000 degrees Celsius. At these temperatures, tungsten will react with ANY gases, except inert ones. But filling light bulbs with helium or neon is too expensive, so the cheapest argon is mainly used. Krypton and xenon are more expensive, but I don’t know what advantage they give, nevertheless they are also used. When water gets on the switched on (and therefore hot) light bulb, the glass simply cracks, but no "explosion" of the light bulb occurs.

You are completely wrong about halogen lamps. Yes, halogens include fluorine, chlorine, bromine, iodine, astatine. As for the ununseptium, you were a bit hasty. Yes, of course, if it can be obtained, then it will undoubtedly refer to halogens. But it has not yet been received, and therefore does not have its own name, only serial number(the number of protons in the nucleus).

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A light bulb is a small but very useful item. Creation video attached.

By definition, an incandescent lamp is an electrical light source where the filament body, which is usually a refractory conductor, is located inside a bulb, evacuated or filled with an inert gas, and heated to a high temperature with the help of an electric current that is passed through it. As a result, visible light is emitted. For the filament, a tungsten-based alloy is used.

incandescent lamp general purpose(230 V, 60 W, 720 lm, base E27, overall height approx. 110 mm

The principle of operation of an incandescent lamp

Well, everything is very simple here. An electric current passes through the incandescent body and heats it up. The filament emits electromagnetic heat radiation, which is in accordance with Planck's law. Its function has a maximum depending on temperature. If the temperature rises, then the maximum shifts towards shorter wavelengths. To...

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Incandescent light bulb

The variety of light sources is quite large, but the incandescent lamp has found the greatest distribution and application. The question arises: "Why exactly did she get such huge popularity and is found at every step?" However, we see other lamps, and if there are alternatives to it, then there will be disadvantages.

In order to evaluate all the advantages and disadvantages, it is necessary to consider the structure of the light source.

Incandescent light bulb consists of:

The variety of flask shapes in most cases is explained by the aesthetic appearance, and sometimes by the possibility of convenient installation. The function of the bulb is to protect the filament from atmospheric precipitation.

Initially, when electric light sources were just being manufactured, a vacuum was created in the glass bulb of the lamp. Currently, this technology is used only for low power(up to 25 W), and light sources of higher power are filled with an inert gas (argon, nitrogen, krypton)....

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The filament in the lamps is heated to high temperatures, which are close to the melting point of tungsten (3422°C). Tungsten, as well as coal, which was used in the first lamps, with room temperature they do not differ in chemical activity, however, a hot tungsten spiral (as well as a carbon filament) burns out in air in a few seconds. This can be easily verified by trying to turn on the incandescent lamp with the bulb removed.

So that the tungsten filament (spiral) does not burn out, it must be isolated from the action of air. The first lamps were vacuum, i.e. air was evacuated from their flasks. Chemists are well aware that glass vessels that work under vacuum can cause a lot of trouble. The slightest damage to the glass or mechanical stress inside the glass - and such a vessel can explode.

Modern lamps are filled with argon or a mixture of krypton and xenon. This is beneficial not only in terms of safety, but also to extend the life of the lamp. Main...

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When did the first incandescent light bulb appear?

In 1809, the Englishman Delarue builds the first incandescent lamp (with a platinum spiral). In 1838, the Belgian Jobar invents the charcoal incandescent lamp. In 1854, the German Heinrich Göbel developed the first "modern" lamp - charred bamboo thread in an evacuated vessel. In 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 long and inefficiently.

First American commercial tungsten filament lamp.

On July 11, 1874, Russian engineer Alexander Nikolaevich Lodygin received a patent number 1619 for a filament lamp. As a filament, he used a carbon rod placed in an evacuated vessel.

In 1875, V. F. Didrikhson improved Lodygin's lamp by pumping ...

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I do not advise, you will not be able to pull it out on your own.

Remember the story about how a taxi driver took a man to the hospital who, on a dare, put an electric light bulb in his mouth, but could not put it back out? The intrigued taxi driver decided to check this story for himself, saying, "how is it, if it enters, then it must exit." And... also went to the doctor. What's the matter?..
EXAMINATION. For the experiment, we bought a standard 60 W light bulb. The “Sloboda” correspondent Dmitry Buzin volunteered to check the anecdote “about the light bulb” on himself: he could not believe that it was impossible to get the light bulb out of his mouth. But... Dmitry still couldn't get it! According to doctors, it is impossible to do this because of a spasm of the muscles of the jaws. Opening the mouth to the maximum width is possible only if the mouth is closed first. If the mouth is already open (for example, two-thirds when the light bulb is in the mouth), the muscles are too tense to open the mouth even more. Only doctors can pull out the light bulb - either with the help of a special ...

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Modern lighting technology is impossible without inert gases. In most types and designs of various light sources, their presence is detected. In some lamps, the noble gases create an inert protective environment. In others, under the influence of electrical discharges, a beautiful colored glow is produced.

When passing electrical discharges in layers of various noble gases, a glow occurs different color. The hue of the glow depends on the properties of the gas itself and on the additional conditions applied to it.

Argon.
It is mainly used in mixtures with other gases. Today, argon is in great demand in lighting engineering. Modern economic, energy-saving or, as they are also called, compact fluorescent lamps filled with a mixture of argon and mercury. The production of such lamps is gaining momentum. Due to their economy, they are becoming more in demand among the population. Therefore, already now, a fairly large part of the argon produced by the industry is used ...

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The most familiar lighting device for us is an ordinary incandescent light bulb. It is a source of illumination, consisting of a glass bulb, an incandescent body, electrodes, a base and an insulator.

They are simple, reliable, and can be purchased at a very low price. Despite the popularity of incandescent lamps, they have several disadvantages. The efficiency of such a device is about 2%, low light output within 20 Lm / W and a short, about 1000 hours, service life.

Principle of operation

When connected to an electrical network, an incandescent lamp converts electrical energy into light energy by heating the conductor (filament) of the filament. Made of refractory tungsten or its alloys, the filament is in a glass bulb filled with an inert gas or vacuum (for low-power lamps up to 25 W).

The device of the light bulb "Ilyich"

The flask serves to protect against exposure external factors, and an inert gas (krypton, nitrogen, xenon, argon and their mixtures) does not allow tungsten ...

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Definition
An incandescent lamp is a light source that converts the energy of an electric current passing through the lamp spiral into heat and light. According to the physical nature, two types of radiation are distinguished: thermal and luminescent.
Thermal radiation is the light emitted
when heating the body. Glow is based on the use of thermal radiation electric lamps incandescent.

Advantages and disadvantages

Advantages of incandescent lamps:
when turned on, they light up almost instantly;
are of small size;
their cost is low.

The main disadvantages of incandescent lamps:
lamps have blinding brightness, which negatively affects human vision, therefore, they require the use of appropriate fittings that limit glare;
have a short service life (about 1000 hours);
life time...

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Halogen lamps, depending on the level of mains voltage, are divided into two types: mains voltage 220-230 V and low-voltage - 12 V or 24 V.

The first group includes a large number of types that differ in power, size, base and purpose. Most often they are used in industry and outdoor lighting. But among them there are lamps and “home” applications with the usual screw base E27 or E14 up to 250 watts. They perfectly replace conventional incandescent lamps. They compare favorably with an almost twofold increase in service life and luminous flux. The main difference from conventional incandescent lamps is that halogen lamps have higher operating temperatures, so you should be guided by the rule: if the cartridge is rated for 150 W, then the power of the "halogen" should not exceed 100 watts.

There are also many types in the low-voltage group, but they have one thing in common - a step-down transformer is required to connect to the network, usually 12 V. V ...

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Among artificial sources Incandescent lamps are the most common lighting. Wherever there is electricity, you can detect the transformation of its energy into light, and incandescent lamps are almost always used for this. Let's figure out how and what heats up in them, and what they are.

Principle of operation and design features

General principle The action of an incandescent lamp consists in the strong heating of the filament body by a stream of charged particles. To emit the spectrum visible to the human eye, the temperature of a luminous object must reach 570 ...

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12

Modern types of lamps that are used to illuminate residential, office, household premises today impress with their diversity. They differ from each other not only in the power of lighting, but also in the principle of operation, as a result - in a variety of shades of light, durability and the amount of electricity consumed.

Accordingly, there are types of lighting lamps that consume a small amount of electricity and at the same time emit bright lighting and a minimum of heat - these lamps are classified as energy-saving lamps, their types are also diverse in design.

New generation types of electric lamps are those that are resistant to voltage drops in the network and have large quantity operating hours and on/off cycles, which, combined with low energy consumption, makes them significantly different from traditional incandescent lamps.

However, modern lighting lamps are not limited to this, they have not only ...

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Incandescent lamps are the most widespread among artificial light sources. Wherever there is an electric current, a transformation of its energy into light can be found, and incandescent lamps are almost always used for this. Let's figure out how and what heats up in them, and what they are.

The features of a particular lamp can be found by examining the index stamped on its metal base.

The index uses the following alphanumeric designations:

• B - Bispiral, argon filling
• BK - Bispiral, krypton filling
• B - Vacuum
• G - Gas-filled, argon filling
• DS, DSh - Decorative lamps
• RN - various purposes
• A - Lampshade
• B - Twisted form
• D - Decorative form
• E - With screw base
• E27 - Plinth version
• Z - Mirror
• ZK - Concentrated light distribution of a mirror lamp
• ЗШ - Wide light distribution
• 215-230V - Recommended voltage scale
• 75 W - Electric power consumption

Types of incandescent lamps and their functional purpose

1. General purpose incandescent lamps

According to their functional purpose, the most common are general purpose incandescent lamps (LON). All LON produced in Russia must comply with the requirements of GOST 2239-79. They are used for outdoor and indoor, as well as for decorative lighting, in household and industrial networks with a voltage of 127 and 220 V and a frequency of 50 Hz.

LONs have a relatively short life, on average, about 1000 hours, and low efficiency - they convert only 5% of electricity into light, and the rest is released as heat.

A feature of low-power (up to 25 W) LON is the carbon filament used in them as a filament. This outdated technology was used in the first "" and was preserved only here.

Seismic-resistant lamps, also included in the LON group, are structurally capable of withstanding a seismic shock with a duration of up to 50 ms.

2. Projector incandescent lamps

Incandescent projector lamps are much more powerful than other types and are designed for directional lighting or giving light signals over long distances. According to GOST, they are divided into three groups: film projection lamps (GOST 4019-74), for general-purpose spotlights (GOST 7874-76) and beacon lamps (GOST 16301-80).

The use of three-wire wiring in a home network provides high level fire safety and reduce the risks to human life. In solving the issue - - it is enough to follow the elementary rules and installation scheme.

For equipment electrical networks residential premises with security equipment, it is necessary to make a choice between installing an RCD or a difavtomat. Can help with this. You can install a difavtomat in several ways, which you can read about.

The filament body in projector lamps is longer and at the same time located more compactly, to enhance the overall brightness and subsequent focusing of the light flux. The task of focusing is solved by special focusing plinths provided in some models, or optical lenses in the designs of searchlights and lighthouses.

The maximum power of projector lamps produced in Russia today is 10 kW.

3. Incandescent mirror lamps

Mirrored incandescent lamps are distinguished by a special bulb design and a reflective aluminum layer. The light-conducting part of the bulb is made of frosted glass, which softens the light and smooths out contrasting shadows from objects. Such lamps are marked with indices indicating the type of light flux: ZK (concentrated light distribution), ZS (medium light distribution) or ZSh (wide light distribution).

This group also includes neodymium lamps, the difference of which is the addition of neodymium oxide to the formula of the composition from which the glass bulb is blown. Due to this, part of the yellow spectrum is absorbed, and the color temperature shifts to the region of brighter white radiation. This allows the use of neodymium lamps in interior lighting for greater brightness and maintaining shades in the interior. The letter "H" has been added to the index of neodymium lamps.

The scope of mirror lamps is huge: shop windows, stage lighting, greenhouses, greenhouses, livestock farms, lighting medical offices and much more.


4. Halogen incandescent lamps

Before you determine which incandescent lamp you need, you should study the features and markings existing types. With all their diversity, you need to accurately understand the purpose of the selected lamp and how and where it will be used. If the characteristics of the lamp do not correspond to the tasks for which it was purchased, it can not only lead to unnecessary costs, but also lead to emergencies up to power failure and fire.

An entertaining video characterizing the work of three types of light bulbs

Despite the active offensive of energy-saving light bulbs, incandescent lamps remain by far the most common source of light. The fundamental design of an electric incandescent lamp has not changed for more than 100 years and consists of a base, contact conductors and a glass bulb that protects the thin spiral of the filament from the environment. The principle of operation of incandescent lamps is based on optical radiation obtained from a conductor heated to a high temperature in an inert environment.

Story

The first electric light source - an electric arc was lit in 1802 by the Russian scientist V.V. Petrov. As a current source, he used a huge battery of 2100 copper-zinc cells, named after one of the creators of electricity Volta, "voltaic". Petrov used a pair of carbon rods connected to different poles of a galvanic battery. When the ends of the rods approached at a close distance, an electric discharge broke through the air gap, while the ends of the rods became white-hot, and a fiery arc appeared between them. It was difficult to use such a lamp - the carbon rods burned quickly and unevenly, and the arc gave out too hot and bright light.

Alexander Nikolaevich Lodygin in 1872 filed an application, and then received a patent (No. 1619, dated July 11, 1874) for a device - an incandescent lamp and a method of cheap electric lighting. He patented this invention first in Russia, and then also in Austria, Great Britain, France, Belgium. In the Lodygin lamp, the heating body was a thin rod of retort coal placed under a glass cap. In 1875, Lodygin's bulbs illuminated Florent's shop on Bolshaya Morskaya Street in St. Petersburg, which was honored to become the world's first shop with electric lighting. The first in Russia installation of outdoor electric lighting with arc lamps was put into operation on May 10, 1880 on the Liteiny Bridge in St. Petersburg. Lodygin's bulbs served for about two months until the coals burned out (there were four such coals in Lodygin's new lamp - when one coal burned out, another took its place).

The Russian scientist Pavel Nikolaevich Yablochkov arranged the coal rods in parallel, separating them with a layer of clay, which gradually evaporated. Yablochkov's "candles" burned with a beautiful pink and purple. In 1877 they illuminated one of the main streets in Paris. And electric lighting began to be called "la lumiere russe" - "Russian light".

Nevertheless, the inventor of the modern electric light bulb is called Thomas Edison. On January 1, 1880, in Menlo Park (USA), a demonstration of electric lighting for houses and streets, proposed by Thomas Edison, was held, which was attended by three thousand people. Edison made the most important improvements in the design of Lodygin's incandescent lamp: he achieved a significant removal of air from the lamp, due to which the incandescent filament shone without burning out.

Edison designed the well-known threaded base of modern lamps, which is named after him. Today, only the first letter "E" in its designation has survived from the full name. In addition, Edison proposed a system for the production and distribution of electricity for lighting.

The improvement of the incandescent lamp continues to this day. Instead of coal, filaments began to be made from heat-resistant metals - first from osmium and tantalum, and then from tungsten. To reduce evaporation and increase strength, since the 1910s, they learned to twist a metal thread into single and repeatedly repeating spirals. In order to prevent metal vapors from settling on the glass, the flasks began to fill it with nitrogen or inert gases.

All this made it possible to increase the luminous efficiency of incandescent lamps from the original 4-6 to 10-15 lm / W, and the service life from 50-100 to the now familiar value of 1000 hours. Development thermal principle obtaining light has found application in halogen incandescent lamps.

Note. Why does hot metal glow? According to quantum theory, if sufficient energy is imparted to an electron in any way, then it will move to a higher energy level, and after 10–13 s it will return to its original ground state, emitting a photon. This fact is due not only to the glow of a hot metal, but also to the "cold" fluorescence of fireflies, in which electrons are excited due to the energy of ATP splitting, as well as the glow of phosphors that have been in the sun, emitting green light in the dark.

Technical information

The luminous efficiency of incandescent lamps is relatively low. It is the lowest among modern electric lamps and lies in the range from 4 to 15 lm / W. The high brightness of the filament, combined with its miniature size, allows the use of incandescent lamps in optical systems and spotlights. Incandescent lamps have a wide range of rated voltages and powers. This type of lamp can operate in a wide range of ambient temperatures, which is limited only by the heat resistance of the materials used in its manufacture (-100...+300°C). The luminous flux of incandescent lamps is regulated by changing the operating voltage, which can be achieved with a dimmer (dimmer) of any design.

However, the disadvantage is the high working temperature and the amount of heat generated during operation. Incandescent lamps are sensitive to water ingress, as a part of the glass bulb will break due to the sudden cooling of a part of the glass bulb, and are potentially fire hazardous due to the high operating temperature.

Today in the world there is a steady downward trend in the share of incandescent lamps in the total volume of lighting fixtures. In the professional sector of the lighting market in developed countries, this share already today does not exceed 10%, being displaced by more economical halogen and LED lighting devices.

The incandescent light bulb is a very important item in human life. With it, millions of people can do business regardless of the time of day. At the same time, the device is very simple in execution: light is emitted by a special filament inside a glass vessel, from which the air is evacuated, and in some cases replaced by a special gas. The filament is made of a conductor with high temperature melting, which makes it possible to heat with a current to a visible glow.

General purpose incandescent lamp (230 V, 60 W, 720 lm, base E27, overall height approx. 110 mm

How an incandescent light bulb works

Working method this device as simple as execution. Under the influence of electricity passed through a refractory conductor, the latter is heated to a high temperature. The heating temperature is determined by the voltage applied to the light bulb.

Following Planck's law, a heated conductor generates electromagnetic radiation. According to the formula, when the temperature changes, the maximum radiation also changes. The greater the heat, the shorter the wavelength of the emitted light. In other words, the color of the glow depends on the temperature of the filament conductor in the light bulb. The wavelength of the visible spectrum is reached at several thousand degrees Kelvin. By the way, the temperature of the Sun is about 5000 Kelvin. A lamp with this color temperature will shine with daylight neutral light. With a decrease in the heating of the conductor, the radiation will turn yellow, then turn red.

In a light bulb, only a fraction of the energy is converted into visible light, the rest is converted into heat. Moreover, only part of the light radiation is visible to a person, the rest of the radiation is infrared. Hence, there is a need to increase the temperature of the radiating conductor so that there is more visible light and less infrared radiation (in other words, an increase in efficiency). But the maximum temperature of the incandescent conductor is limited by the characteristics of the conductor, which does not allow it to be heated up to 5770 Kelvin.

A conductor made of any substance will melt, deform, or cease to conduct current. Currently, light bulbs are equipped with tungsten filaments that can withstand 3410 degrees Celsius.
One of the main properties of an incandescent lamp is the glow temperature. Most often, it is between 2200 and 3000 Kelvin, which allows only yellow light to be emitted, and not daylight white.
It should be noted that in air the tungsten conductor at this temperature will immediately turn into oxide, in order to avoid which contact with oxygen must be prevented. To do this, air is pumped out of the bulb, which is enough to create 25-watt lamps. More powerful light bulbs contain a pressurized inert gas inside them, which allows the tungsten to last longer. This technology allows you to slightly increase the temperature of the glow of the lamp and get closer to daylight.

Incandescent light bulb device

Light bulbs vary slightly in design, but the main components include a filament of a radiating conductor, a glass vessel, and terminals. At the lamps special purpose there may not be a base, there may be other holders of the radiating conductor, one more bulb. Some incandescent lamps also have a ferronickel fuse located in the gap of one of the terminals.

The fuse is located mainly in the leg. Thanks to him, the bulb is not destroyed when the radiating conductor breaks. When the lamp filament breaks, an electric arc appears, melting the remains of the conductor. The molten substance of the conductor, falling on the glass flask, is able to destroy it and provoke a fire. The fuse is destroyed by high current electric arc and stops the filament from melting. But they did not install such fuses due to their low efficiency.

The design of the incandescent lamp: 1 - bulb; 2 - the cavity of the flask (vacuum or filled with gas); 3 - glow body; 4, 5 - electrodes (current inputs); 6 - hooks-holders of the body of heat; 7 - lamp leg; 8 - external link of the current lead, fuse; 9 - base case; 10 - base insulator (glass); 11 - contact of the bottom of the base.

Flask

The glass bulb of an incandescent lamp protects the radiating conductor from oxidation and destruction. The bulb size depends on the deposition rate of the conductor material.

Gas medium

The first light bulbs were produced with a vacuum flask, in our time only low-power devices are made this way. More powerful lamps are produced filled with an inert gas. Radiation of heat by an incandescent conductor depends on the value of the gas molar mass. Most often, the flasks contain a mixture of argon and nitrogen, but it can also be just argon, as well as krypton and even xenon.

Molar masses of gases:

• N2 - 28.0134 g/mol;
• Ar: 39.948 g/mol;
• Kr - 83.798 g/mol;
• Xe - 131.293 g/mol;

Separately, it is worth considering halogen lamps. Halogens are pumped into their vessels. The filament conductor material evaporates and reacts with the halogens. The resulting compounds decompose again at high temperatures and the substance returns to the radiating conductor. This property allows you to increase the temperature of the conductor, as a result of which the efficiency and duration of the lamp increases. In addition, the use of halogens makes it possible to reduce the size of the flask. Of the minuses, it is worth noting the small resistance of the filament conductor at the start.

Filament

The forms of the radiating conductor are different, depending on the specifics of the light bulb. Most often, light bulbs use a round filament, but sometimes a ribbon conductor can also be found.
The first light bulbs were produced even with coal heated up to 3559 degrees Celsius. Modern light bulbs are equipped with a tungsten conductor, sometimes with an osmium-tungsten conductor. The type of spiral is not accidental - it significantly reduces the dimensions of the filament conductor. There are bispirals and trispirals obtained by the method of repeated twisting. These types of filament conductor make it possible to increase efficiency by reducing heat radiation.

Incandescent light bulb properties

Light bulbs are produced for various purposes and installation locations, which is the reason for their difference in circuit voltage. The magnitude of the current is calculated according to the law of the well-known Ohm (voltage divided by resistance), and the power using a simple formula: multiply the voltage by the current or divide the voltage squared by the resistance. To make an incandescent bulb of the required power, a wire with the necessary resistance is selected. Typically, a conductor with a thickness of 40-50 microns is used.
When starting, that is, turning on the light bulb in the network, a current surge occurs (an order of magnitude greater than the nominal one). This is due to the low temperature of the filament. After all, at room temperature, the conductor has little resistance. The current is reduced to the nominal only when the filament is heated due to an increase in the resistance of the conductor. As for the first carbon lamps, it was the other way around: a cold bulb had more resistance than a hot one.

plinth

The base of the incandescent lamp has a standardized shape and size. Thanks to this, it is possible to replace a light bulb in a chandelier or other device without problems. The most popular are threaded bulb sockets marked E14, E27, E40. The numbers after the letter "E" indicate the outer diameter of the base. There are also light bulb bases without thread, held in the cartridge by friction or other devices. Light bulbs with E14 sockets are more often required when replacing old ones in chandeliers or floor lamps. The E27 base is used everywhere - in cartridges, chandeliers, special devices.
Please note that in America the circuit voltage is 110 volts, so they use different plinths from European ones. In American stores there are light bulbs with E12, E17, E26 and E39 sockets. This was done in order not to accidentally confuse a European light bulb rated for 220 volts and an American one for 110 volts.

Efficiency

The energy supplied to an incandescent light bulb is spent not only on the production of a visible spectrum of light. Part of the energy is spent on the emission of light, part is converted into heat, but the largest share is spent on infrared light, which is inaccessible to the human eye. At an incandescent conductor temperature of 3350 Kelvin, the light bulb efficiency is only 15%. And a standard 60-watt lamp with a glow temperature of 2700 Kelvin has an efficiency of about 5%.
Naturally, the efficiency of a light bulb directly depends on the degree of heating of the radiating conductor, but with more strong heat thread will not last long. At a conductor temperature of 2700K, the bulb will shine for about 1000 hours, and when heated to 3400K, the service life is reduced to several hours. When the lamp supply voltage is raised by 20%, the luminous intensity will increase by about 2 times, and the operating time will decrease by up to 95%.
To increase the life of the light bulb, you should lower the supply voltage, but this will also reduce the efficiency of the device. At serial connection incandescent bulbs will last up to 1000 times longer, but their efficiency will be 4-5 times less. In some cases, this approach makes sense, for example, on flights of stairs. High brightness is not required there, but the service life of the bulbs should be considerable.
To achieve this goal, a diode must be connected in series with the light bulb. A semiconductor element will cut off the half-period current flowing through the lamp. As a result, the power is reduced by half, and after it the voltage is reduced by about 1.5 times.
However, this method of connecting an incandescent lamp is unprofitable from the economic point of view. After all, such a chain will consume more electricity, which makes it more profitable to replace a burned-out light bulb with a new one than the kilowatt-hours spent to extend the life of the old one. Therefore, to power incandescent bulbs, a voltage is applied that is slightly larger than the nominal voltage, which saves electricity.

How long does a lamp last

The life of the lamp is reduced by many factors, for example, the evaporation of a substance from the surface of the conductor or defects in the filament conductor. With different evaporation of the conductor material, sections of the thread appear with high resistance, causing overheating and even more intense evaporation of the substance. The filament under the influence of such a factor becomes thinner and completely evaporates locally, which causes the lamp to burn out.
The filament conductor wears out the most during startup due to the inrush current. To avoid this, soft start lamp devices are used.
Tungsten is characterized by a specific resistivity of the substance 2 times greater than, for example, aluminum. When the lamp is connected to the network, the current flowing through it is an order of magnitude greater than the nominal one. Current surges are what cause incandescent bulbs to burn out. To protect the circuit from surges in light bulbs, there is sometimes a fuse.

Looking closely at the light bulb fuse seen more thin conductor going to the plinth. When a conventional electric 60-watt light bulb is connected to the network, the power of the filament can reach 700 watts and more, and when a 100-watt one is turned on, more than 1 kilowatt. When heated, the radiating conductor increases resistance and the power decreases to normal.

To ensure a smooth start of the incandescent lamp, you can use a thermistor. The temperature resistance coefficient of such a resistor must be negative. When included in the circuit, the thermistor is cold and has a high resistance, so the light bulb will not receive full voltage until this element warms up. These are just the basics, the topic of smoothly connecting incandescent bulbs is huge and requires more in-depth study.

Thanks to the table below, you can approximately find out the ratio of power and luminous flux for ordinary light bulb"pears" (base E27, 220 V).

What are incandescent light bulbs

As mentioned above, air has been evacuated from the incandescent lamp vessel. In some cases (for example, at low power), the flask is left vacuum. But much more often the lamp is filled with a special gas, which prolongs the life of the filament and improves the light output of the conductor.
According to the type of filling the vessel, light bulbs are divided into several types:
Vacuum (all the first light bulbs and low-power modern ones)
Argon (in some cases filled with a mixture of argon + nitrogen)
Krypton (this type of light bulbs shines 10% more than the above-mentioned argon lamps)
Xenon (in this version, the lamps already shine 2 times stronger than lamps with argon)
Halogen (iodine, possibly bromine, is placed in the vessels of such bulbs, allowing it to shine as much as 2.5 times stronger than the same argon ones. This type light bulb is durable, but requires a good filament glow to operate the halogen cycle)
Xenon-halogen (such lamps are filled with a mixture of xenon with iodine or bromine, which is considered best gas for light bulbs, because such a source shines 3 times brighter than a standard argon lamp)
Xenon-halogen with IR reflector (a huge proportion of the glow of incandescent bulbs is in the IR sector. By reflecting it back, you can significantly increase the efficiency of the lamp)
Lamps with an incandescent conductor with an IR radiation converter (a special phosphor is applied to the glass of the bulb, which emits visible light when heated)

Pros and cons of incandescent lamps

Like other electrical appliances, light bulbs have a lot of pluses and minuses. That is why some people use these light sources, while the other part has opted for more modern lighting fixtures.

Pros:

Good color rendering;
Large-scale established production;
Low cost of the product;
Small size;
Ease of execution without unnecessary knots;
Radiation resistance;
Has only active resistance;
Instant start and restart;
Resistance to voltage drops and network failures;
Contains no chemical harmful substances;
Work both from AC and DC;
Lack of input polarity;
Production under any tension is possible;
Doesn't flicker off alternating current;
Does not buzz from AC;
Full light spectrum;
Habitual and comfortable color glow;
Resistance to electromagnetic field impulses;
It is possible to connect the brightness control;
Glow at low and high temperatures, resistance to condensation.

Minuses:

• Low luminous flux;
  Short duration of work;
  Sensitivity to shake and shock;
  Large current surge at start-up (an order of magnitude higher than the nominal);
  If the filament conductor breaks, the bulb may be destroyed;
  Lifetime and light output depends on voltage;
  Fire hazard (half an hour of glow of an incandescent lamp heats up its glass depending on the power value: 25W to 100 degrees Celsius, 40W to 145 degrees, 100W to 290 degrees, 200W to 330 degrees. Upon contact with the fabric, the heating becomes more intense. 60-watt light bulb can, for example, set fire to straw after an hour of work.);
  The need for heat-resistant lamp holders and fasteners;
  Low efficiency (the ratio of the strength of visible radiation to the amount of electricity consumed);
  Undoubtedly, the main advantage of an incandescent lamp is its low cost. With the spread of luminescent and, moreover, LED light bulbs her popularity has declined significantly.

Do you know how incandescent lamps are made? Not? Then here is an introductory video from Discovery

And remember, a light bulb stuck in your mouth won't come out, so don't do it. 🙂