To create artificial lighting, an ordinary incandescent lamp is often used. This element is familiar to everyone since the days of the USSR. Glass bulb, cartridge and spiral are the main visible parts of the product. How an incandescent lamp is arranged inside is interesting for both a novice master and a professional.
History of the invention of the bulb
The product was designed and developed by many scientists in different periods. The first electric arc was ignited by the scientist Petrov V.V. in 1802. The invention consisted of two carbon rods that were connected to the poles of a galvanic battery. At the moment of their approach, an electric discharge arose, and a luminous arc formed over the elements. The use of such a lamp in everyday life was impossible for a number of reasons - the inconvenience of the design, the rapid burning of coal rods. But world scientists began to understand what to make a lamp of.
After 70 years in 1872, Lodygin A.N. received a patent for an incandescent lamp. A retort coal rod, which was located under a glass hood, was used as a spiral in it.
Already in 1880, on May 10, Lodygin's bulb was equipped with street lighting in St. Petersburg on Liteiny Bridge. The life of the light source was only 2 months (until the carbon rod burned out).
In 1880, Thomas Edison introduced the improved Lodygin incandescent lamp in the United States. He managed to achieve the elimination of air from the glass bulb, which ensured a longer burning of the spiral and a brighter glow. Edison also designed a threaded socket for screwing a lamp into a socket.
In 1910, it was decided to twist the tungsten filament in a spiral to increase its service life. Thus, the product now works instead of the initial 50-100 hours for as much as 1000 hours.
The principle of thermal radiation is also used in the production of halogen fluorescent lamps.
What the lamp consists of
The structure and scheme of an incandescent lamp look like this:
- a glass bulb of a pear-shaped or rounded shape;
- glow body (tungsten or charcoal filament) located in it on two hook holders;
- two electrodes;
- fuse;
- leg;
- socle (case) with an insulator;
- his contact (bottom).
Oxidation of a tungsten filament (spiral, glow body) is excluded due to its placement in a vacuum or gaseous medium. They fill a glass flask.
Electrical parameters
All bulbs are made for different voltages. Since tungsten refractory metal has a low resistivity, a long wire is needed for the device of the light element. Thus, the filament in an electric bulb often reaches 50 micrometers. When light is turned on, a current passes through the glowing body, exceeding the working one by 10-14 times. The more the thread warms up, the stronger the resistance of the thread increases and the current decreases.
The principle of operation of an electric incandescent lamp
Having considered what a light bulb consists of, it is important to understand the principle of its operation:
- When light is turned on, a current flows through the bottom of the cap to the glow body.
- The tungsten filament is very hot after the circuit is closed, which leads to its glow.
- At this point, the temperature of the thread reaches 570 degrees.
- Thus, the spectrum of the glow of the bulbs is shifted towards warm temperatures.
For reference: the lower the degree of the tungsten / carbon filament, the lower will be the fraction of energy that comes to the glowing body and provokes its visible radiation. Retro lamps differ in that they heat up the spiral more slowly and more weakly.
Varieties of light elements
All products are classified according to different parameters. By the type of filling of the bulb, these lamps are distinguished:
- the simplest vacuum (when they are made from the flask, all air is sucked out);
- filled with argon gas;
- xenon halogen;
- filled with krypton.
By type of purpose, the bulbs are divided into the following types:
- Decorative. They work according to the usual principle. The flask is made in the form of a candle or ball.
Decorative incandescent bulbs - General purpose. These are familiar to all ordinary elements that are screwed into a chandelier or sconce. Often masters are concerned with the question of how many watts a light bulb consumes. You can buy a product for 40, 60, 90, 100, 120, 150, 200 and more watts. The higher the indicator, the brighter the glow.
- Lamps for local lighting. Structurally, they are no different from ordinary elements. But the operating voltage for them is in the range of 12-42 V.
- Bulbs for illumination. They have a flask painted in bright colors. Operating power in the range of 10-25 watts.
- Signaling. They have extremely low power and are used for lighting devices. Today, such products are confidently superseded by modern LED lamps.
- Spotlights. The glow body is laid in a special way due to its convenient suspension in the bulb. As a result, it is possible to achieve better focusing of the glow. The power of such lamps reaches 10-50 kilowatts.
Mirror lamp - Mirrored. They have a special flask coating. It is partially covered with a film of thermally sprayed aluminum. Thus, it is possible to achieve a narrow directivity of the light beam. DSLRs are used for local lighting.
- Transport. These products are characterized by increased strength, resistance to vibration. For transport lamps, special socles are used, thanks to which you can quickly replace the lighting element in the cramped conditions of the machine. Such elements work from the power supply of a car 6-220 V.
- Products for optical instruments. Today almost never released. Previously used for film projectors, medical equipment. Lamps of this type have a flask of a special shape.
- Switch light. Relate to the class of signal. They have a small bulb size, which allows them to be placed under the buttons of the panels of various installations.
Double-strand warning light
By the number of filaments, all elements are:
- Double thread. They have one glowing body for distant (strong) light and one for dipped (weak) lighting. Used in cars, aviation, railway traffic lights, in the stars of the Moscow Kremlin.
- Single stranded. Familiar tungsten light bulbs.
The body of low-inertia products has an extremely thin spiral. Previously, they were used for optical sound recording systems. There are also heating lamps that are used to arrange drying chambers, electric stoves, office equipment, etc.
Advantages and disadvantages
Incandescent lamps have a number of advantages:
- reasonable cost;
- compact dimensions;
- instant reaction to on / off;
- lack of flicker, adversely affecting the eyes;
- inertia to power surges;
- soft gamma of glow, contributing to relaxation, creating an atmosphere of comfort;
- good color rendering index equal to Ra 90;
- work in any conditions (including high humidity);
- constant availability for the consumer;
- environmental friendliness;
- lack of noise during the work;
- inertness to ionizing radiation.
The disadvantages of incandescent lamps include such moments:
- fragility, sensitivity to mechanical damage;
- relatively short life;
- low efficiency, not exceeding 5-7% (the ratio of consumed power to visible radiation);
- fire hazard with direct contact of the lamp with combustible substances (textiles, straw, etc.);
- the likelihood of an explosion due to thermal shock or rupture of a spiral under tension.
Despite all these shortcomings, familiar bulbs confidently retain their positions. More than 70% of the CIS population still uses them.
Efficiency and Durability
When analyzing how an incandescent lamp is arranged, it is important to understand its efficiency. At a light temperature of 3400 Kelvin, the efficiency of the element is 15%. This refers to the ratio of power consumption to visible light visible to the human eye. At a temperature of 2700 K (average normal for an ordinary household lamp), the efficiency is only 5%.
The higher the temperature of the glow, the greater the efficiency. But at the same time, the life of the product is reduced. For example, if you increase the voltage by 20%, the brightness of the illumination will become stronger - the efficiency of the bulb will increase, however, the service life will be reduced by 90-95%. Accordingly, a decrease in voltage leads to a decrease in the efficiency of the product and an increase in its useful life.
How to increase the life of an incandescent lamp
On average, an ordinary household incandescent light bulb lasts 700-1000 hours. But in fact, the element burns out much faster. To extend the life of the bulb, it is necessary to prevent factors that cause the burnout of the spiral.
- Observe voltage range. It is indicated on the flask of the product. As a rule, it is equal to 125-135 W, 220-230 W, 2.3-2.4 kW. If the voltage in the house is exceeded, the product will burn out sooner. For example, in an apartment the maximum voltage is 220 V, and the lamp was purchased with a range of 125-135 V. Here, the filament will burn out unambiguously faster, since the efficiency of the product increases.
- Repair cartridge malfunction. If the lamps burn out often, it is worth examining it, double-checking the contacts. If necessary, change the cartridge.
- Eliminate vibration. They lead to rapid burnout of the tungsten filament. Therefore, the transfer of mobile fixtures is best done with the bulb turned off.
To extend the life of the incandescent lamp, you can reduce the voltage in the network by only 7-8%. In this case, the product will last 3-3.5 times longer with economical energy consumption.
