Learn on Lights
T5 Tube Light
Light is the source of life. From the sunrise to sunset, our life is colorful with sunlight. But now nights are also equally colorful and bright. Man has learnt the secret of producing light in other ways too - incandescent bulbs, fluorescent bulbs, lasers, lightning bugs etc. Each one uses a different technique to generate photons. Light is electromagnetic radiation of a wavelength that is visible to the human eye (in a range from about 380 or 400 nanometers to about 760 or 780 nm).
Electromagnetic Spectrum
Light waves come in a continuous variety of sizes, frequencies and energies. We refer to this continuum as the electromagnetic spectrum. In this spectrum, visible light occupies only one-thousandth of a percent of the spectrum. Sun was the only source of light for earth. With time men learnt to use fire. Oil lamps, torches, candles are different ways in which fire has been used to give us light. It was not until the end of the 19th century that advances in material research (leading to the tungsten filament) enabled electric lamps to be produced in quantity. A short time later came the first discharge lamps. The incandescent light bulb is a source of electric light that works by incandescence (a general term for heat-driven light emissions, which includes the simple case of black body radiation). An electric current passes through a thin filament, heating it to a temperature that produces light. The enclosing glass bulb contains either a vacuum or an inert gas to prevent oxidation of the hot filament. Incandescent bulbs are also sometimes called electric lamps.

Incandescent bulbs are made in a wide range of sizes and voltages, from 1.5 volts to about 300 volts. They require no external regulating equipment and have a low manufacturing cost, and work well on either alternating current or direct current. As a result the incandescent lamp is widely used in household and commercial lighting, for portable lighting such as table lamps, car headlamps, and flashlights, and for decorative and advertising lighting.
Electromagnetic Spectrum
History of the light bulb
In 1802, Humphry Davy created the first incandescent light by passing the current through a thin strip of platinum. Platinum was chosen as the metal had an extremely high melting point. It was not bright enough nor did it last long enough to be practical, but it was the precedent behind the efforts of scores of experimenters over the next 75 years. In 1809, Davy also created the first arc lamp with two carbon charcoal rods connected to a 2000-cell battery. Over the first three-quarters of the 19th century many experimenters worked with various combinations of platinum or iridium wires, carbon rods, and evacuated or semi-evacuated enclosures.
Sir Humphry Davy
There is a list of 22 inventors of incandescent lamps prior to Thomas Edison. Historians conclude that Edison's version was able to outstrip the others because of a combination of three factors: an effective incandescent material, a higher vacuum than others were able to achieve (by use of the Sprengel pump) and a high resistance that made power distribution from a centralized source economically viable.

In 1877, Edison decided to enter the highly publicized race for a successful light bulb and enlarged his laboratory facilities with a machine shop and an office and research library. The staff grew from 12 to over 60 as Edison tackled the entire lighting system, from generator to insulator to incandescent bulb. Along the way, Edison created a new process of invention, orchestrating a team approach that brought financing, materials, tools, and skilled workers together into an "invention factory." Thus, the search for the light bulb illustrated new forms of research and development that were later developed by General Electric, Westinghouse, and other companies.
Thomas Alva Edison
Edison's first successful light bulb model
The Manufacturing Process
The uses of light bulbs range from street lights to automobile headlights to flashlights. For each use, the individual bulb differs in size and wattage, which determine the amount of light the bulb gives off (lumens). However, all incandescent light bulbs have the three basic parts—the filament, the bulb and the base. Originally produced by hand, the light bulb manufacture is now almost entirely automated.
  • The filament is manufactured through a process known as drawing, in which tungsten is mixed with a binder material and pulled through a die—a shaped orifice—into a fine wire. Next, the wire is wound around a metal bar called a mandrel in order to mold it into its proper coiled shape, and then it is heated in a process known as annealing. This process softens the wire and makes its structure more uniform. The mandrel is then dissolved in acid.
  • The coiled filament is attached to the lead-in wires. The lead-in wires have hooks at their ends which are either pressed over the end of the filament or, in larger bulbs, spot-welded.
Filament: Image 1
Filament: Image 2
Filament: Image 3
Filament: Image 4
Glass bulb
  • The glass bulbs or casings are produced using a ribbon machine. After heating in a furnace, a continuous ribbon of glass moves along a conveyor belt. Precisely aligned air nozzles blow the glass through holes in the conveyor belt into molds, creating the casings. A ribbon machine moving at top speed can produce more than 50,000 bulbs per hour. After the casings are blown, they are cooled and then cut off of the ribbon machine. Next, the inside of the bulb is coated with silica to remove the glare caused by a glowing, uncovered filament. The company emblem and bulb wattage are then stamped onto the outside top of each casing.
Glass Bulb
  • The base of the bulb is also constructed using molds. It is made with indentations in the shape of a screw so that it can easily fit into the socket of a light fixture.
Bulb Base (B22)
  • Once the filament, base, and bulb are made, they are fitted together by machines. First, the filament is mounted to the stem assembly, with its ends clamped to the two lead-in wires. Next, the air inside the bulb is evacuated, and the casing is filled with an argon and nitrogen mixture. These gases ensure a longer-life for the filament. The tungsten will eventually evaporate and break. As it evaporates, it leaves a dark deposit on the bulb known as bulb-wall blackening.
  • Finally, the base and the bulb are sealed. The base slides onto the end of the glass bulb such that no other material is needed to keep them together. Instead, their conforming shapes allow the two pieces to be held together snugly, with the lead-in wires touching the aluminum base to ensure proper electrical contact. After testing, bulbs are placed in their packages and shipped to consumers.
Fitted Bulb: 1
Fitted Bulb: 2
Quality Control
Light bulbs are tested for both lamp life and strength. In order to provide quick results, selected bulbs are screwed into life test racks and lit at levels far exceeding their normal burning strength. This provides an accurate reading on how long the bulb will last under normal conditions. Testing is performed at all manufacturing plants as well as at some independent testing facilities. The average life of the majority of household light bulbs is 750 to 1000 hours, depending on wattage.
A compact fluorescent lamp (CFL), also known as a compact fluorescent light or energy saving light (or less commonly as a compact fluorescent tube), is a type of fluorescent lamp. Many CFLs are designed to replace an incandescent lamp and can fit into most existing light fixtures formerly used for incandescent.

Compared to general service incandescent lamps giving the same amount of visible light, CFLs use less power and have a longer rated life.

CFLs radiate a different light spectrum from that of incandescent lamps. Improved phosphor formulations have improved the subjective color of the light emitted by CFLs such that some sources rate the best 'soft white' CFLs as subjectively similar in color to standard incandescent lamps.
A compact fluorescent lamp of "Spiral" Shape

How CFL Works - Click here
The most important technical advance has been the replacement of electromagnetic ballasts with electronic ballasts; this has removed most of the flickering and slow starting traditionally associated with fluorescent lighting.

There are two types of CFLs: integrated and non-integrated lamps.
A compact fluorescent lamp.
There are two main parts in a CFL: the gas-filled tube (also called bulb or burner) and the magnetic or electronic ballast. An electrical current from the ballast flows through the gas (mercury vapor), causing it to emit ultraviolet light. The ultraviolet light then excites a phosphor coating on the inside of the tube. This coating emits visible light.

An electronic ballast and permanently attached lamp tube in an integrated compact fluorescent lamp.

There are different standard shapes of tubes: single-turn double helix, double-turn, triple-turn, quad-turn, circular, and butterfly.

Electronic ballasts contain a small circuit board with rectifiers, a filter capacitor and usually two switching transistors connected as a high-frequency resonant series DC to AC inverter. The resulting high frequency, around 40 kHz or higher, is applied to the lamp tube. Since the resonant converter tends to stabilize lamp current (and light produced) over a range of input voltages, standard CFLs do not respond well in dimming applications and special lamps are required for dimming service. CFLs that flicker when they start have magnetic ballasts; CFLs with electronic ballasts are now much more common.
An electronic ballast and permanently attached lamp tube in an integrated compact fluorescent lamp.
Integrated CFLs
Integrated lamps combine a tube, an electronic ballast and either an Edison screw or a bayonet fitting in a single unit. These lamps allow consumers to replace incandescent lamps easily with CFLs.

Integrated CFLs work well in many standard incandescent light fixtures, reducing the cost of converting to fluorescent.

Special 3-way models and dimmable models with standard bases are available.
Non-integrated CFLs
Non-integrated CFLs have the ballast permanently installed in the luminaries and only the lamp bulb is usually changed at its end of life. Since the ballasts are placed in the light fixture they are larger and last longer compared to the integrated ones, and they don't need to be replaced when the bulb reaches its end-of-life. Non-integrated CFL housings can be both more expensive and sophisticated.

There are two types of tubes: a bi-pin tube designed for conventional ballast, and a quad-pin tube designed for electronic ballast or conventional ballast with an external starter.

A bi-pin tube contains an integrated starter which obviates the need for external heating pins but causes incompatibility with electronic ballasts.
Non-integrated bi-pin double-turn compact fluorescent lamp
Non-integrated electronic ballast for compact fluorescent lamps
CFL power sources
CFLs are produced for both alternating current (AC) and direct current (DC) input. DC CFLs are popular for use in recreational vehicles and off-the-grid housing.

CFLs can also be operated with solar powered street lights, using solar panels located on the top or sides of a pole and light fixtures that are specially wired to use the lamps.
Comparison with incandescent lamps

The average rated life of a CFL is between 8 and 15 times that of incandescent. CFLs typically have a rated lifespan of between 6,000 and 15,000 hours, whereas incandescent lamps are usually manufactured to have a lifespan of 750 to 1,000 hours.
Energy efficiency
The chart shows the energy usage for different types of light bulbs operating at different light outputs. Points lower on the graph correspond to lower energy use.

For a given light output, CFLs use 20 to 33 percent of the power of equivalent incandescent lamps.

Electrical power equivalents for differing lamps
Compact Fluorescent (W) Incandescent (W) Minimum light output (lumens)
9 - 13 40 450
13 - 15 60 800
18 - 25 75 1,100
23 - 30 100 1,600
30 - 52 150 2,600
Energy efficiency
Heating and cooling
If a building's indoor incandescent lamps are replaced by CFLs, the heat produced due to lighting will be reduced. If the building requires both illumination and cooling, then CFLs also reduce the load on the cooling system compared to incandescent lamps, resulting in two concurrent savings in electrical power.
Efficacy and efficiency
The luminous efficacy of CFL sources is typically 60 to 72 lumens per input watt of electric power, versus 8 to 17 lm/W for incandescent lamps. This gives an efficiency range of 17 to 21% of a theoretical ideal white light source giving 347 lumens per radiant watt for a tri-phosphor spectrum.
Embodied energy
While CFLs require more energy in manufacturing than incandescent lamps, this embodied energy is more than offset by the fact that they last longer and use less energy than equivalent incandescent lamps during their lifespan.
While the purchase price of an integrated CFL is typically 3 to 10 times greater than that of an equivalent incandescent lamp, the extended lifetime and lower energy use will more than compensate for the higher initial cost. CFLs are extremely cost-effective in commercial buildings when used to replace incandescent lamps.
Environmental issues
CFLs, like all fluorescent lamps, contain small amounts of mercury as vapor inside the glass tubing. Most CFLs contain 3 – 5 mg per bulb, with some brands containing as little as 1 mg. Because mercury is poisonous, even these small amounts are a concern for landfills and waste incinerators where the mercury from lamps may be released and contribute to air and water pollution.

Net mercury emissions for CFL and incandescent lamps, based on EPA FAQ sheet, assuming average US emission of 0.012 mg of mercury per kilowatt-hour and 14% of CFL mercury contents escapes to environment after land fill disposal.
Mercury emissions by light source
T5 Tube Light
T5 fluorescent lamp is the first linear lamp type to be served only by electronic ballasts. It is smaller than T8 and T12 lamps, with a miniature bi-pin base. The numerical designation refers to the diameter of the lamp in eighths of an inch—so the T5 lamp is five-eighths inch in diameter, compared to 1 inch for T8s and 1-1/2 inches for T12s. The narrower profile means that the lamps provide designers with better optical control and better fixture efficiency. It is notable for its lumens-per-watt efficiency, due to its peak light output occurring at 35 °C (95 °F) air temperature rather than the 77°F design point for most other lamps.

Those characteristics allow the use of the lamps in more compact fixtures than would otherwise be possible, but also mean that steps must be taken to keep the lamps warm in colder environments, such as unheated warehouses.

T5s are often applied in low-profile fixtures, such as those used for cove lighting and illuminating display cases. Indirect and indirect/direct fixtures also often feature T5 lamps—the thinness and high intensity of the lamps enable designers to place fixtures farther apart and closer to the ceiling than is possible with T8 lamps.
T5 Tube Light
The T5 fluorescent lamp entered the market in the United States in 1995.
Shape and size
The "T" in the lamp’s name denotes the shape of the lamp-tubular. The number 5 represents the diameter of the lamp in eighths of an inch. T5 high output (HO) lamps have the same diameter and length as standard T5 lamps. Because the T5 has a smaller diameter, the luminaries can fit in narrow spaces easily and may be ideal for indirect lighting for cove, cabinet, display, and pendant applications.
T5 lamps need special ballasts to operate. There are three types of ballasts available for T5 lamps: instant start, rapid start, and programmed start electronic ballasts. T5 lamps operate at frequencies greater than 20 kilohertz. Most manufacturers claim that their T5 ballasts have a total harmonic distortion (THD) of less than 15%. Most T5 ballasts are very quiet and carry class “A” sound ratings. Dimmable ballasts exist for T5 lamps.
Energy efficiency
The T5 lamp provides peak light output at 35 °C (95 °F) air temperature. (By contrast, the T8 and the T12 lamps provide peak light output at a 25 °C [77 °F] ambient air temperature.) The T5 lamp has a higher lumens-per-watt efficiency than a T8 lamp of about the same wattage, in a space where there is little or no air circulation.

Also, the so-called "high output" T5 lamps have lower efficacy than the "high efficiency" series (lamp nominal powers 14, 21, 28 and 35 W). Care is needed to specify the latter lamps, if very high energy efficiency is wanted.

T5 lamps are a popular energy-efficiency measure, due to their potential to cut energy use in lighting by more than 60%.

4’ Linear Fluorescent Bulbs Lumen Output
28 Watt T5 2900 lumens
54 Watt T5 5000 lumens
25 Watt T8 2209 lumens
32 Watt T8 2850-3100 lumens
34 Watt T12 1930-2800 lumens
40 Watt T12 1980-3300 lumens

T5 luminaries that utilize a sleep mode or motion sensors to operate can generate even larger cost savings. In a 2008 field test in a warehouse scenario, using a standard T5 lighting system as a replacement to a metal halide system had potential cost savings of 23%. However, when using a T5 system with a sleep mode to replace a metal halide system, building owners had potential cost savings of 34-75% depending on sleep and wake control modes used.
Mercury content
The T5 lamp has a low mercury content. Each new generation of fluorescent lighting technology, including the T5 generation, has been able to function with less mercury, but perform with the same or greater efficiency. The lamp has a coating on the inside of the glass wall that stops the glass and phosphors from absorbing mercury. This barrier coating reduces the amount of mercury needed from approximately 15 mg to 3 mg per lamp. Since mercury absorption causes the lamp’s light output to depreciate over its life, the coating helps to keep light levels much closer to initial output—only 5% depreciation in the first 40% of its life.
T5 bulbs have smaller bulb diameters than T8 bulbs, but produce roughly the same amount of light. T5 bulbs produce 2,900 lumens. T8 bulbs produce 2,950 lumens and T12 bulbs only produce anywhere from 1930-3300 lumens. The fact that T5 bulbs can produce an almost equivalent amount of light with a smaller diameter means that the surface luminance of T5 bulbs is 1.64 times that of the T8 lamp. Because of the increased surface luminance, glare can be a problem with T5 bulbs, but it is more an issue with T5 High Output bulbs (5000 lumens) than the T5 High Efficiency bulbs (2,900 lumens). However, there are two simple solutions that can prevent glare from becoming a problem:
  • Placing the bulbs out of direct line of sight or using an indirect luminaire will eliminate this problem.
  • If using a direct luminary, parabolic louvers, metal mesh filters, shields or diffusers will help reduce glare.
Some T5 lighting systems can operate using a wireless system. The wireless system can change the lighting mode.

Some T5 lighting systems can utilize motion sensor systems, although sensitivity to the motion varies from system to system.
Cost per Watt
A case study conducted by the Institute of Electrical Engineers demonstrates that T5 lighting is a more cost-effective solution than LED lighting. The study compared a T5 fluorescent light to a T8 sized LED bulb to determine $/1000 lm for each technology. Study results show that T5 bulbs perform at a source cost of approximately $3 per 1000 lm, whereas the best comparable LED bulb costs more than $70 per 1000 lm.
Differences from other fluorescent lamps
T5 lamps are approximately 40% smaller than T8 lamps and almost 60% smaller than T12 lamps. T5 lamps have a miniature bi-pin base, while T8 and T12 lamps use a medium bi-pin base.

A fluorescent lamp’s "cold spot" is the area on the lamp where the temperature is at its lowest. This cold spot rises or falls along with the ambient temperature of the lamp. Unlike a T8 or T12 fluorescent lamp, where the cold spot is in the middle, in T5 lamps it is at the end, on the metallic cap, about 2 mm from the glass envelope.

T5 lamps generally last for 20,000 hours, as compared to T8 lamps, which last for 15,000 hours.

These differences in dimension prevent T5 lamps from being used as replacements for T8 and T12 lamps, unless the existing luminaries are electronically converted via T5 retrofit conversion, to high frequency operation, so that they can accept the T5 lamps.
7 million lamps