Fluorescent lamps are what? Types of fluorescent lamps

In January of this year, General Electric (GE) announced the discontinuation of the production of compact fluorescent lamps in the US by the end of 2016. The new LED technology has dared to become habitual luminescent from its path, as it once overthrew the "rule" of incandescent lamps invented by GE founder Thomas Edison.

So what is a fluorescent lamp?

Fluorescent lamps are low-pressure mercury gas-discharge illuminators in which fluorescence is used to emit visible light. The electric current in the gas excites mercury vapor, which begins to emit light in the ultraviolet range, which causes the phosphor coating to glow.

There are the following types of fluorescent lamps: cold cathode, hot start and electroluminescent lamps.

Hot start

The most common are hot start lamps. A light source of this type consists of a glass bulb filled with an inert gas (usually argon) of low pressure. A tungsten electrode is located on each side of the bulb. Ballast regulates the power of the electrodes. In old lamps, a starter was used to start them. In modern electronic ballasts are used.

They are somewhat like incandescent lamps. The initial glow is produced by a heated spiral of tungsten, but then an electric discharge in a mixture of mercury vapors and inert gases causes ultraviolet radiation. A special composition that covers the walls of the bulb absorbs ultraviolet and emits visible light. It is called a phosphor and is a mixture of compounds based on phosphorus. Thanks to it, the luminous flux of such lamps is several times higher than that of incandescent lamps. The filament continues to glow at the end of the ignition, but only to maintain the discharge.

To create an electrical discharge, a high voltage is necessary . The colder the colder, the higher this parameter. But, since high indicators are dangerous, the means of "warming up" the bulb for reducing the voltage have been developed.

One of the warm-up methods is to use a starter. When the voltage is applied, a discharge lamp is lit, heating the bimetallic contacts. Contacts are closed, shunted, and electric current heats the tungsten electrodes, which in turn heat and ionize the inert gas. Having cooled down, bimetallic contacts open, supplying all the voltage, as well as throttle energy to the electrodes. If the discharge does not occur, the process will be repeated. After ignition of a lamp the starter will be disconnected, as its resistance much exceeds the resistance of plasma.

In modern fast start systems, the electrodes are constantly heated, and the arc is initiated by a grounded reflector or starting strip.

Cold cathode fluorescent tubes

Cold cathode fluorescent lamps are devices whose cathode temperature does not exceed 150 ° C compared to 900 ° C of hot-start lamps. The operating voltage is 600-900 V, the starting voltage is 900-1600 V. The light is emitted by ionized gas, which requires high voltage to create it. The discharge occurs when the space between the electrodes breaks down. The gas in a lamp under normal conditions is a dielectric, but in an electric field the ions and electrons move. When a high voltage is applied, the electric field so accelerates the charged particles, which, colliding with the gas molecules, knock out electrons from them. Newly created ions and electrons are also involved in ionization: the process becomes avalanche-like.

In hot-start lamps, the discharge is arc, and the light sources of the cold discharge are smoldering. Gradually, mercury passes from the liquid state to the gaseous state. Electrons, colliding with mercury atoms, initiate the release of energy and intense radiation in the ultraviolet region. The light is emitted by the phosphor coating inside the bulb. Mercury emits photons that excite phosphorus atoms, increasing the energy of its electrons. When electrons return to the initial state, phosphorus atoms emit light energy.

Electroluminescent lamps

The radiation of light in electroluminescent lamps occurs due to the passage of an electric current directly through phosphorus-containing materials with the effect of nonthermal conversion of electricity into light. This effect is also used in LED (LED) and organic light-emitting diodes (OLED). Electroluminescent lamps differ from LEDs in that in the latter the light is emitted in the pn junction - the junction of the two semiconductors, while in the former the light is radiated by the entire activator layer.

A high-voltage alternating electric current passes through a thin layer of phosphorus or semiconductor, which has the effect of emitting light to it. Two layers of a solid, one of which is transparent, act like electrodes, and the powdered phosphorus or conductor between them glows when electrons pass through it.

Arguments for

• Such lighting devices can serve dozens of times longer than incandescent lamps under condition of stable power supply without significant voltage fluctuations and limiting the number of inclusions. When you turn on the electrodes, the special composition that protects the tungsten filament from overheating and ensures the discharge stability, burns out and falls, which reduces the life of the light source. The ends of the bulb darken, and the lamp begins to flicker.
• Luminous efficiency of fluorescent lamps per unit of power consumption is approximately 3-4 times greater than that of incandescent lamps.
• They are diverse in color, their emission spectrum is closer to solar.
• Diffused glow from the entire surface of the bulb, not the tungsten filament.

Minuses

• Relatively high cost.
• Fluorescent lamps are a potential source of danger, since each flask contains up to 5 mg of mercury, which is very toxic and can harm health and the environment.
• Gas discharge lamps are sensitive to low and high temperatures. Can not operate at temperatures below -20 ° C and above +50 ° C.
• Sensitive to humidity.
• Delay on, as it takes time to warm up the lamp.
• Unusual for the vision of the light spectrum, the consequence of which is the distortion of color perception. Flicker at a frequency of twice the frequency of the mains.

Criterias of choice

1. Form and dimensions. Glass bulbs and cartridges vary greatly in these parameters. The usual form of fluorescent fixtures is a straight tube. Its diameter is a multiple of one eighth of an inch. So, the size of a lamp with a diameter of 1 inch is T8. The size ranges from T2 to T17. Compact fluorescent lamps, as a rule, have a U-shape and a spiral shape. Of course, the appearance does not affect the operation of the lamp, but the spiral models cost a little more, since their production is more complicated.

2. Start. Possible with a starter, electronic or with electromagnetic ballast.

3. Power. Waves from 3 to 85 watts. The light flux of incandescent lamps is 3-4 times lower than that of luminescent ones, therefore, the required power should be selected based on the required brightness. Fluorescent lamps, whose power is 25-30 W, will replace the usual 100-watt electrical appliances. To replace a 75-watt enough energy-saving light source of 9 watts. And fluorescent lamps, whose power is 15 watts, will be able to replace a 60 W incandescent lamp.

Table of the ratio of the light flux and the power consumption of lamps of different types will help to understand all the nuances.

4. The plinth. The following types are common:

• Bayonet B;
• Screw (edison) socket E;
• One-sided two-contact G.

The number after the letter denotes either the diameter of the socle of type B or E, or the distance between the contacts in mm in the socles of type G.

Basically, chandeliers and sconces use compact fluorescent lamps with a E27 base 27 mm in diameter and E14 minions with a diameter of 14 mm.

5. The color of light. Corresponds to the temperature of a blackbody radiating with a certain chromaticity. As the temperature rises, the blue part of the spectrum increases, while the red part decreases. It is measured in kelvins. The subjective sensation of a person looking at a light of a certain color is called a color sensation. The main colors of light and their corresponding color perception:

• 2700 K - super warm white;
• 3000 K - warm white light;
• 3500 K - white light;
• 4000 K - cold white light;
• 5000 K and more - daylight.

6. Color reproduction. Shows how natural the surrounding objects look in the light of the lamp. It is measured by the color rendition coefficient Ra. Light sources with equal chromaticity can have different color rendition due to different spectrum of emitted light. For the sunlight the coefficient is 100.

Marking

Manufacturers of lamps celebrate the products in different ways.

In the USA, fluorescent lamps are usually labeled according to the template FxxTy, where F is the fluorescent type, the first number xx is either the power in watts or the length in inches, the T-shape (English tubular, tubular) and the last number y - 1/8 inch diameter (3.175 mm).

Then follows the letter designation of chromaticity:

• WW - Warm White, warm white.
• CW - Cool White, cool white.
• N - Neutral, neutral.
• D - Daylight, daylight.
• WWX - Deluxe Warm White, warm white with high color rendition.
• CWX - Deluxe Cool White, cool white with high color rendering.
• BLB - Blacklight, ultraviolet.

At the very end of the marking, the features of the device are indicated:

• RS - Rapid Start, quick start.
• IS - Instant Start, instant start.
• HO - High Output, high efficiency.

Characteristics of fluorescent lamps

The General Electric Candle T2 9 Watt lamp is available with E14 and E27 caps, 405 lumens nominal light output, warm white and daytime color temperature (2700 K and 6500 K), color rendition index 82 Ra. It is used in chandeliers and other lamps with a visible bulb in rooms, corridors and halls of trading halls, hotels, restaurants, dwellings.

Philips products

Master TL-D 90 De Luxe - fluorescent lamp G13, T8, with color rendition index 93 Ra8, color temperature 65000 K - cold daylight. Available in three versions:

• 18W / 965 1SL - 18W fluorescent lamps with a nominal luminous flux of 1150 lumens and a nominal light output of 63.9 Lm / W;
• 58W / 965 1SL - 58-watt light sources with a nominal luminous flux of 4550 lumens and a nominal light output of 77.8 Lm / W;
• 36W / 965 1SL - 36W fluorescent lamps with a nominal luminous flux of 2800 lumens and a nominal light output of 77.8 Lm / W.

A high color rendering index allows you to see rich, juicy and natural colors, which makes the lamp irreplaceable in hospitals, printing houses, beauty salons, museums, dentistry offices and shops. Lamps are distinguished by high-quality luminescent coating with the use of three-way phosphorus and almost complete absence of decrease in the level of illumination.

Master TL-D Xtreme 36W / 840 1SL - fluorescent lamp 36-watt power, two-pin, cold white color with a color rendering index of 85 Ra8, a nominal light flux of 3250 lumens, a nominal luminous efficiency of 90 lm / W. Its feature is an extended service life of up to 66,000 hours, which is important for places where the cost of replacing lamps is high because of the height of the room, the need for interruption of work, or where the light is constantly on fire - in tunnels, drilling rigs, in continuous production.

Master PL-C 18W / 830 / 2P 1CT is a two-contact 18-watt fluorescent lamp with G24d-2-cap, warm white color of 3000 K, color rendition index of 82 Ra8, a nominal luminous flux of 1200 lumens, a nominal luminous efficiency of 67 lm / W. Designed for general top lighting in leisure facilities, retail and office buildings. The Philips Master Pl-C luminescent lamp uses the original bridge connection technology, which guarantees optimum performance, better lighting and high efficiency. The two-contact model has a removable base and is used with the EMPA.

Energy-saving light sources from Osram

Osram produces compact fluorescent 18W DSST FCY 18 W / 825 E27 lamps with a warm color of 2500 K, with a color rendering index of 80, a light flux of 1050 lumens and an E27 cartridge. The device is able to withstand a very large number of start-up cycles - up to 1 million.

Osram Lumilux T9 C is a 29 mm annular luminaire with G10Q cartridge, rated power 22 W, color temperature 2700 K, color rendering index 80-89, rated light flux 1350 lumens and rated light output 61 Lm / W. It is intended for public buildings, restaurants, manufactures, shops, supermarkets, hotels. It is distinguished by economy, good quality of light, excellent luminous flux, uniform illumination without shadows. Adjustment of brightness is allowed.

L 36 W / 840-1 - 1-meter linear lamps, fluorescent, 36 W, with G13 base, color temperature 4000 K, rated light flux 3100 lumens, color rendering index 80 Ra, nominal luminous efficiency 86 Lm / W. Are intended for illumination of public transport.

Endura 70 W / 830 is an electrodeless Osram light source with a power of 70 W, a nominal luminous flux of 6200 lumens of warm white with a temperature of 3000 K, a color rendering index of 80-90 Ra, and a light output of 80 lm / W. It is used for lighting tunnels, manufactures, streets, sports grounds. It has a long service life (up to 100 000 hours), economy, high light flux, instant start.

Electrodeless fluorescent lamps are devices in which discharge occurs in a high-frequency electromagnetic field created by magnetic circuits on a flask. Magnetic cores play the role of the primary winding of the transformer, and the gas discharge is secondary. The characteristics of fluorescent lamps of this type are reduced to the following: the devices are stable, they serve for a long time due to the absence of collapsing electrodes.

DSST SENSOR CL A 15 W / 827 E27 is a fluorescent lamp rated at 15 watts, with a nominal light flux of 870 lumens, warm white light at a temperature of 2700 K. It is characterized by increased efficiency due to automatic switching-off during daylight. It is intended for external use only.