What are fluorescent lamps? Types of Fluorescent Tubes

In January of this year, General Electric (GE) announced the cessation of the production of compact fluorescent lamps in the United States by the end of 2016. The new LED technology swept out of its way that managed to become habitual luminescent, as it once overthrew the "board" of incandescent lamps invented by GE founder Thomas Edison.

So what is a fluorescent lamp?

Fluorescent lamps are low-pressure mercury discharge lamps that use fluorescence to emit visible light. The electric current in the gas excites mercury vapors, which begin to emit light in the ultraviolet range, which causes the glow of the internal phosphorus coating.

The following types of fluorescent lamps are distinguished: cold cathode, hot start, and electroluminescent.

Hot start

The most common are hot start lamps. This type of light source 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 controls the power of the electrodes. In old lamps, a starter was used to start them. In modern electronic ballasts are used.

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

To create an electric discharge , a high voltage is required. The colder the bulb, the higher this parameter. But, since high rates are dangerous, means were developed to “warm up” the flask to reduce voltage.

One method of warming up is to use a starter. When voltage is applied, a discharge lamp is lit, heating the bimetallic contacts. The contacts close, shunt it, and an electric current heats the tungsten electrodes, which, in turn, heat and ionize the inert gas. Cooling, bimetallic contacts open, supplying all the voltage, as well as the energy of the inductor to the electrodes. If the discharge does not occur, the process will be repeated again. After ignition of the lamp, the starter will turn off, since its resistance is much higher than the plasma resistance.

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 a high voltage to create. A discharge occurs when the space between the electrodes is broken. The gas in a lamp is an insulator under normal conditions, but ions and electrons move in an electric field. When a high voltage is applied, the electric field accelerates the charged particles so much that when they collide with gas molecules, they knock electrons out of them. The newly created ions and electrons are also involved in ionization: the process becomes avalanche-like.

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

Electroluminescent lamps

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

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

Arguments for

• Such lighting devices can serve ten times longer than incandescent lamps, provided that they are provided with stable power without significant voltage fluctuations and the number of switches is limited. When turned on, a special composition burns out and falls off on the electrodes, which protects the tungsten filament from overheating and ensures discharge stability, 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 closer to the sun.
• Scattered light from the entire surface of the bulb, not a 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 be harmful to health and the environment.
• Discharge lamps are sensitive to low and high temperatures. May not work at air temperatures below -20 ° C and above +50 ° C.
• Sensitive to humidity.
• On delay because it takes time to warm up the lamp.
• The light spectrum, unusual for vision, results in distortion of color perception. Flicker with a frequency twice the frequency of the mains.

Criterias of choice

1. Shape and size. Glass bulbs and cartridges are very different in these parameters. A common form of fluorescent lights is a straight tube. Its diameter is a multiple of one eighth of an inch. So, the size of the lamp with a diameter of 1 inch is T8. Size varies from T2 to T17. Compact fluorescent lamps, as a rule, have the shape of a U-shaped and spiral. Of course, the appearance does not affect the operation of the lamp, but spiral models are a little more expensive, since their production is more complicated.

2. Start. It is possible with a starter, electronic or with electromagnetic ballast.

3. Power. Fluctuates from 3 to 85 W. The luminous flux of incandescent lamps is 3-4 times lower than that of fluorescent ones, so you need to choose the required power based on the required brightness. Fluorescent lamps, the power of which is 25-30 watts, will replace conventional 100-watt electrical appliances. To replace the 75-watt enough energy-efficient light source of 9 watts. And fluorescent lamps, whose power is 15 watts, will be able to replace a 60-watt incandescent lamp.

A table of the relationship between the luminous flux and the power consumption of lamps of different types will help to understand all the nuances.

4. The basement. The following types are common:

• bayonet mount B;
• screw (Edison) base E;
• one-sided two-contact G.

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

Mostly chandeliers and sconces use compact fluorescent lamps with an E27 base with a diameter of 27 mm and E14 minions with a diameter of 14 mm.

5. The color of the light. Corresponds to the temperature of a black body radiating with a certain chromaticity. With increasing temperature, 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 rendering. Shows how naturally surrounding objects look in the light of a lamp. Measured by the color rendering coefficient Ra. Light sources with equal color may have different color reproduction due to the different spectrum of emitted light. For sunlight, the coefficient is 100.

Marking

Lamp manufacturers mark products differently.

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

The following is the letter designation of color:

• 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 rendering.
• CWX - Deluxe Cool White, cool white with high color rendering.
• BLB - Blacklight, UV.

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

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

Characteristics of fluorescent lamps

Decorative lamp General Electric Candle T2 with a power of 9 W is available with E14 and E27 sockets, a nominal luminous flux of 405 lumens, warm white and day color temperature (2700 K and 6500 K), and a color rendering index of 82 Ra. It is used in chandeliers and other lamps with a visible bulb in rooms, corridors and halls of trading floors, hotels, restaurants, homes.

Philips Products

Master TL-D 90 De Luxe - fluorescent lamp G13, T8, with a color rendering index of 93 Ra8, color temperature of 65,000 K - cold daylight. Available in three versions:

• 18W / 965 1SL - 18 W luminescent 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 4,550 lumens and a nominal light output of 77.8 Lm / W;
• 36W / 965 1SL - 36 W 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, rich and natural colors, which makes the lamp indispensable in hospitals, printing houses, beauty salons, museums, dentistry rooms and shops. The lamps are distinguished by a high-quality luminescent coating using three-band phosphorus and an almost complete absence of a decrease in the level of lighting.

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

Master PL-C 18W / 830 / 2P 1CT is a two-contact 18-watt fluorescent lamp with a G24d-2 base, warm white 3000 K, with a color rendering index of 82 Ra8, a nominal luminous flux of 1200 lumens, a nominal light output of 67 Lm / W. Designed for general overhead lighting in leisure facilities, retail and office buildings. The Philips Master Pl-C fluorescent lamp uses the original bridge technology to guarantee optimum performance, better lighting and high efficiency. The two-pin model has a removable base and is used with EMPR.

Energy Saving Light Sources from Osram

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

Osram Lumilux T9 C is a 29-mm ring-shaped luminaire with a G10Q lampholder, rated power 22 W, color temperature 2700 K, color rendering index 80-89, nominal luminous flux 1350 lumens and nominal light output 61 Lm / W. Designed for public buildings, restaurants, industries, shops, supermarkets, hotels. It is distinguished by efficiency, good quality of light, excellent luminous flux, uniform lighting without shadows. Adjustable brightness.

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

The Endura 70 W / 830 is an Osram electrodeless light source with a power of 70 W, a nominal luminous flux of 6200 lumens, warm white at 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, industries, streets, sports fields. It features a high service life (up to 100,000 hours), efficiency, high luminous flux, instant start.

Electrodeless fluorescent lamps are devices in which a discharge occurs in a high-frequency electromagnetic field created by magnetic circuits on the bulb. Magnetic cores play the role of the primary winding of the transformer, and the gas discharge is secondary. The characteristics of this type of fluorescent lamps are as follows: 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 15 W fluorescent lamp with a nominal light output of 870 lumens and warm white light at a temperature of 2700 K. It is characterized by increased efficiency due to automatic shutdown during daylight hours. Designed for external use only.