Light sources

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Light sources

The basic division of light sources distinguishes between natural and artificial ones. The first group includes stars, active volcanoes, but also some living organisms. Artificial light sources are primarily various types of lamps and light bulbs.

Due to the way electricity is converted into visible radiation, the following electric light sources can be distinguished:

temperature (e.g. light bulbs) - luminous flux is generated as a result of thermal radiation in the filament,
discharge (e.g. fluorescent lamps - fluorescent lamps, mercury lamps, sodium lamps) - luminous flux is created as a result discharge electric in rarefied in pairs mercury,
temperature discharge (e.g. mercury-incandescent lamps, xenon lamps, arc lamps),
other (special purpose).

When designing or analyzing the condition of electric lighting, it is necessary to determine its basic parameters, i.e. lighting class, type of light source, required and actual intensity lighting, types and arrangement of luminaires and lighting uniformity.

Basic types of artificial light sources

Light sources should be selected primarily depending on their intended use, and thus the expected properties. A different bulb will be needed in a dark workshop and a different one in a desk lamp. It is important e.g. whether the models are resistant to moisture, dust and impacts, how much energy they use in operation and how long they last.

Here are the most important parameters that determine the purpose and use of a given light source:

luminous flux,
luminous efficiency,
light color,
color rendering index,
durability understood as the time during which the light source was lit before it expired or ceased to meet certain requirements,
power,
sensitivity to voltage fluctuations,
construction of a lighting fixture,
shank type,
finish,
net weight.

The el.12 store's offer includes the following types of light sources:

incandescent,
low pressure,
diesel,
halogen,
led.

Incandescent light sources

Incandescent light sources are popular light bulbs (in various versions) as well as radiators and reflectors. For traditional light bulbs, the value of the supply voltage is constant and determined by the value of the mains voltage, which in Poland is 230V.

The first incandescent lamps were created in the mid-nineteenth century. In incandescent bulbs, the light source is a filament made of a hard-to-fusible material heated up by the current flow. Originally, graphite was used for this type of application, now it is tungsten.

A standard bulb consists of a glass bulb and a cap. To prevent tungsten from oxidizing, it is necessary to enclose it in a vacuum or in a glass bubble filled with noble gases.

Why does a bulb burn out over time? The higher the temperature of the filament, the more energy is emitted, some of which is emitted in the visible range. However, when the temperature is raised, the tungsten begins to evaporate, and its particles settle in the cooler areas of the lamp in the form of a thin coating on the inner wall of the bulb. This phenomenon, over time, reduces the amount of light emitted. In order for the tungsten to be deposited on the largest possible surface (and thus limiting the emission of light as little as possible), the bulb bulb is relatively large. As a result of evaporation, the tungsten wire becomes thinner and thinner until it burns through.

Low pressure light sources

Low-pressure lamps are primarily fluorescent and induction lamps. In the assortment of the el.12 store, the following subcategories can be found in this category:

integrated compact fluorescent lamps,
non-integrated compact fluorescent lamps,
linear fluorescent lamps,
round fluorescent lamps,
specialty fluorescent lamps,
U-shaped fluorescent lamps.

Fluorescent lamps (or fluorescent lamps) are the most popular group of so-called discharge lamps and can often be found in outdoor and indoor lighting installations. Fluorescent lamps are successfully used in public spaces (e.g. in shops, offices, production halls, garages, parking lots, sports halls), as well as in private houses and apartments.

In fluorescent lamps, the luminous flux arises as a result of discharge electric in rarefied mercury vapor and converting invisible ultraviolet radiation into radiation of a selected color of light. This process takes place with the participation of a properly selected phosphor (chemical compound showing luminescence or phosphorescence), covering the inside of the glass tubes of the lamps. Due to the structure of the fluorescent lamp, these devices can be divided into standard and those with a compact structure.

High pressure light sources

In this category, the el12.pl offer includes the following types of light sources:

metal halide bulbs (these are discharge lamps in which light is generated by an electrical discharge in a mixture of mercury vapor, argon and metal halides).
mercury bulbs (discharge medium is mercury vapor),
sodium bulbs (the discharge medium is sodium vapor).

In high-pressure mercury lamps, the luminous flux is created as a result of an arc discharge in high-pressure mercury vapor (up to 2 MPa), sometimes with the addition of halogens. Light color correction from blue-green to white (daylight) is made in a phosphor covering the inner surface of the bulb.

High pressure sodium lamps work similarly to mercury lamps. The source of light is a tube containing a portion of sodium, mercury and ignition gas (argon or xenon). After the voltage is switched on, as a result of the ignition system, impulses are generated which cause the xenon discharge to ignite. As the temperature of the glow tube increases, the sodium inside it begins to evaporate. The lamp begins to change the color of the light. After reaching the pressure of about 0.1 MP inside the arc tube, the discharge stabilizes.

Due to the high luminous efficiency and the resulting energy savings, sodium lamps have practically replaced the previously used mercury lamps. Sodium lamps are divided into low and high pressure.

Halogen light sources

A halogen lamp is a gas-filled incandescent lamp containing a tungsten strand and a small amount of halides. The halogen bulb is a more modern and slightly more complicated variant of the classic filament bulb, because it has a tungsten filament, which is placed inside a bulb filled with a noble gas with the addition of halogen - e.g. iodine. This device is distinguished by greater energy efficiency, no dimming at the end of use and a longer operating time. It is worth noting that halogen bulbs also give whiter light, making them very friendly to human eyes.

In this category, the el12 offer includes the following light sources:

halogen spotlights,
halogen linear,
halogen low voltage,
230 V halogen lamps.

LED light sources

The light source in LED lamps is a white light-emitting diode, which usually consists of: a blue light-emitting diode and a phosphor. In the case of general lighting, it is popular to use blue LED light sources and cover them with chemicals that change the light spectrum. Thanks to the use of several coatings, the spectrum of light can be made similar to that emitted by the sun.

In this category, the el.12 offer includes the following devices: