incandescent lamp was the second form of electric light to be developed
for commercial use after the carbon arc lamp.
It is the second most used lamp in the world today behind fluorescent
lamps. In this page we cover the traditional incandescent lamp. Halogen
lamps are also incandescent light sources, but they have their own page
here. The traditional incandescent bulb is
not just a light source but has become a symbol of innovation.
*Great for small area lighting
*Good color rendering: CRI of 100 which is the best possible
*Cheap to produce
*No quantity of toxic materials to dispose of (like mercury, toxic alloys,
*Is easily used in strobe or dimming circuits
*Not energy efficient (90% of energy goes to heat, 10%
makes visible light)
*Traditional incandescent light bulbs are not useful for lighting large
areas. It takes many to light a large area where as only one HID lamp
can light a large open area. Halogen incandescent is useful for this
purpose but it is not covered on this page.
100 (best CRI possible)
*Color Temperature - comes in all variations, but normally 2700
per watt 8 - 24
*Lamp life: 750 - 1000 hrs (standard household bulb)
life can be greatly extended by using the lamp at a lower than
uses: used everywhere for almost any application. From 1-10,000
Video on the incandescent lamp. 6 min. YouTube must
not be blocked by your server.
How it Works
bulbs work by sending electric current through a resistive material.
Typically materials will glow before reaching a melting point. Most
materials will glow a dull red color when they reach around 525 Celsius.
Most materials will catch fire or melt and can not make a good filament.
are made from materials that have a high melting point. Tungsten
can reach up to 3422 C before it melts. This is a higher temperature
than any lamp will reach (except the carbon arc lamp which gets to 3500
C). Other materials have made good filaments or parts of filaments including
tantalum, molybdenum, and carbon.
does the material emit light when you pass electrical current through
When you pass
current through a filament material, the resistance creates heat. Atoms
in the material absorb energy. Electrons around the atoms are excited
and temporarily reach an orbital which is further from the nucleus.
When the electron orbit collapses to a lower orbital it ejects the extra
energy in the form of a photon.
Incandescence is thermal radiation. Heat is constantly emitted from
objects around us, we just can't see it. When heat gets intense enough
it reaches wavelengths that we can see. It starts with red and goes
up the spectrum. The wavelength/color of the light is a matter of how
much energy is being released and what kind of atom is doing the release.
In an incandescent bulb most of the heat energy (90%) is emitted in
the infrared spectrum which is just below visible light. This is also
what makes the lamp inefficient. We don't use that part of the spectrum
for the lamp's purpose, we only need the visible spectrum. This is a
basic explanation. More can be read about the chemistry from your textbook
History and Developments
history of the incandescent bulb is centered on the development
of filament types, so we will organize it by filaments.
and Iridium Filaments: 1802 -1880's
Humphry Davy created the first incandescent light by passing
current through a platinum strip. It caused a glow and did not
last long, but marked the beginning of incandescent light development.
Experimenters continued over the next 70 years to use platinum
and iridium. Frederick de Moleyns used a platinum filament
in an evacuated glass tube to make a light bulb. It was only mildly
successful due to a blackening of the bulb, which blocked light
output. Combustion of the filament material and blackening on
the upward side of the bulb was a frustrating consistent problem
for early lamp inventors. The platinum material was also expensive.
inventors knew that making a vacuum in a bulb would help reduce
blackening and lengthen bulb life, the problem was ways to better
create a vacuum had to be developed. Heinrich Geissler was one
of the early physicists to develop a good pump and system. Still,
early bulb inventors 1802 - 1879 lacked a system good enough.
As is typical with invention, many know the answer, but other
technological developments are needed to move forward.
of the incandescent bulb, video:
Threads and Paper: 1860's - 1883
Joseph Swan and Thomas Edison independently hit
success by making a bulb that would last a reasonable number of
Swan used carbonized paper to create his early filaments.
first used carbonized sewing thread as a filament, he managed
to get it inside a vacuum. This made his first practical lightbulb.
He used carbonized sewing threads until 1880. Then he used paper
bristol board. (Carbonized paper) This move increased lamp life
to 600 hours.
Edison Triumphed: Joseph Swan worked on the incandescent light
idea since 1850. Swan did not succeed because he used only a partial
vacuum in his bulb. He also used a carbonized paper filament.
Edison figured out how to create a pure vacuum in his bulbs. He
did this by heating up the bulb at the same time that he pumped
out the air. He used a Sprengle
Pump to the left was used by Swan and Edison to pump air
from the first light bulbs. Read more about the pump by
clicking on the
Scientific American article above.
Bamboo brings great improvements:
1883: As the story goes Edison was using a fan on a hot day, he
unwound fine bamboo on a fold-out oriental fan. He carbonized
it and tested it as a filament. He send assistants to Japan to
find the type of bamboo that was used in that fan. They found
it and imported the filaments.
first bamboo filaments had a square shape because they were cut
from larger pieces using a certain process. He electroplated the
bamboo directly to the lead in wires to avoid the high cost of
platinum clamps. Later he used carbon paste to adhere the bamboo
to the lead in wires.
video about early Edison Bulbs with cellulose and bamboo filaments:
Filaments: 1881 - 1904
Joseph Swan developed the cellulose filament in 1881, however
Edison continued to use bamboo filaments until the creation of
General Electric in 1892. Cellulose filaments were replaced by
Willis Whitney's GEM lamp filaments.
about the Mazda Bulb:
move to metallic filaments: The Era of Tantalum
Tantalum Filaments: 1902
was the first metal filament on the market. Like tungsten
it has a very high melting point, so it can be heated
to incandescence without destroying itself like most metals.
Tantalum was so vastly superior to all other filaments
that it became king from 1902 - 1909. After 1909 the sintered
tungsten lamp really began to gain popularity. The arrival
of a ductile tungsten finally ended the reign of tantalum.
Werner von Bolton(a Georgian
living in Germany) discovered that using tantalum for
a filament allowed for lower energy consumption and greater
brightness. Siemens and Halske Company produced these
bulbs. The tantalum filament became successful and became
a major threat to General Electric's sales. This stimulated
GE to invest more in it's recently formed research lab
to try to come up with a better lamp.
A lit Tantalum Lamp on display at Siemens Forum in Munich,
The hooks used to hold filament
WOTAN Lamp, made with a drawn-tungsten
WOTAN was a
trademarked name owned by Siemens & Halske
Lamp Metallized Filaments: 1904 - 1907
Whitney of GE Schenectady develops a way to bake a carbon
filament at 3000 C to create a filament that behaves much like
metal. This improves efficiency by 25 %. This filament was used
in the famous Mazda lamps which produced a very bright
Tungsten Filaments: 1904 -1911
1904 sintered tungsten is developed by Alexander Just and Franz
Hanaman (Austria). Tungsten improves the lamps efficiency by 100
% and is used by GE in 1907 after it buys the rights for it.
*Tungsten and Molybdenum filaments were used by A.N. Lodygin (Russia)
in a 1900 "Exposition Universelle" in Paris
Tungsten Filaments: 1908
D. Coolidge had been working with tungsten which proved to
be a superior material for a long lasting lightbulb over any other
material to date. Previous sintered tungsten filaments had been
efficient, but brittle and not practical. Coolidge figured out
how to heat tungsten and draw it out through heated dies of decreasing
diameter. The result of his work was a workable, bendable (ductile)
wire that was high strength and made a great filament material.
The new material was used in bulbs in 1911 and this is still used
today. See our inventors section below
for more advancements in the incandescent bulb.
future of incandescent lamps:
Incandescent lamp has been in the average household for more than
120 years. In the last decade a major initiative to develop
more efficient lightbulbs has replaced much of the world's bulbs
with compact fluorescents. There has been significant resistance
to bans on the incandescent bulb
3. Inventors and Developments
Sir Humphry Davy discovers incandescence in a
platinum wire. He also is the discoverer of the first electric
lamp type: the carbon arc lamp. England
Frederick de Moleyns patented a incandescent lamp
within a glass bulb and a partial vacuum. He is one of many
people working on the incandescent light bulb from 1840 to the
1870s. Many French and Germans contributed to research on the
incandescent bulb. Moleyns is exceptional and helped others
build on the idea. England
Sir Joseph Swan began working with the incandescent
light long before Edison, however his biggest breakthrough was
developed at the same time as Edison. Swan used carbonized paper
as a filament in a partially evacuated bulb, this lasted several
hours, which was a great achievement compared to the scores
of inventors who couldn't get incandescence to last. Swan continued
to improve the bulb. England
Thomas Edison is the most celebrated of incandescent
inventors. He was able to succeed in creating the first reliable
(therefore marketable) light bulb. His bulbs made after 1880
lasted a whopping 600 hours. He then hired lots of talented
engineers and created the world's most famous "invention
factory". West Orange, New Jersey
Werner von Bolton discovered that using tantalum
for a filament increased efficiency, durability and bulb life.
The age of metallic filaments had begun and Siemens and Halske
held the patent. Germany
Willis Whitney counters the threat from the tantalum
lamp with the GEM lamp: a unique process which creates a metallized
filament. The GEM lamp is used in the Mazda series by General
Electric. Schenectady, New York
Alexander Just and Franz Hanaman patent a sintered
tungsten filament. Tungsten proves to be a good material, however
it is fragile and hard to work with. It is a step towards the
modern bulb Austria
William D. Coolidge revolutionizes the lightbulb
by figuring out how to make tungsten ductile. This allows the
lightbulb to be more durable, long lasting, and easily coiled
(coiling is key to making more surface area and therefore more
light). The invention is implemented in 1911. His invention
is used in many other lamp types later on including the fluorescent,
halogen, MH, mercury vapor, and other lamps. Schenectady, New York
Irving Langmuir developed 3 important improvements
to the bulb: He worked with Lewi Tonks to develop an argon &
Nitrogen-filled bulb, he also developed the tight coiled filament,
and pioneered a thin molecular hydrogen coating on the inside
of the bulb. All of these dramatically improved the bulb. Schenectady, New York
Junichi Miura at Tokyo Electric (this facility is now part of Toshiba)
developed the double
coiled filament. This greatly improved luminous efficacy and
helped efficiency. Later others figured out how to mass produce this improvement.
Notice on the photo left how the large coil is made of another
/ 1947 Marvin Pipkin developed
the frosted etched bulb and later the silica coating on the
inside of the bulb. These advancements helped diffuse the light,
reduce glare with only 3-5% loss in light output. Cleveland, Ohio
a Philips flashbulb with magnesium filament Photo: Wikipedia Commons
traditional flashbulb is another type of incandescent lightbulb. Early
flash bulbs used a aluminum, zirconium, or magnesium filament or aluminum
foil. Current was passed through the material and it glowed. The melting
and boiling point of aluminum, magnesium or zirconium is so low that
the lamp would vaporize the metal, which further intensified the brightness.
Early lamps would last one flash and had to be replaced. Early flashbulbs
often had an Edison type screw in thread like a regular lightbulb. Later
lamps could last a few flashes. Later on disposable flash bulb arrays
were developed to allow many flashes without switching bulbs.
of the greatest challenges in developing a flash bulb is not the bulb
itself, but timing the bulb to match the camera shutter. This improved
with the development of solid state electronics in the 1950s.
flashbulbs found on most cameras are no longer incandescent bulbs.
They are tiny xenon arc tubes. An electric arc is formed through xenon
gas. These have the great advantage of being reusable. They have the
disadvantage of being a shorter duration than incandescent flash bulbs.
This means they have to be more precisely time
1927?? at General Electric and Johannes
Ostermeier both independently develop the first non-magnesium
electric flashbulb. It is much safer than older bulbs. The General
Electric Product is called the Sashalite. This light replaced
dangerous magnesium powder lights. The new lamps burned aluminum
foil in a bulb filled with oxygen. Ostermeier produced a product
called the Vacublitz. Schenectady, New York
1934Philips Corp. Unknown inventor created the first
modern flashbulb: it has a wire in an evacuated bulb. The wire
burns ups in a more effective way than aluminum sheets of foil.
This design has not changed much. Nederlands
1960s?? at Kodak develops the flashcube which has
four single use small flash bulbs. The cube can be rotated to
use the new bulb.
1968John D. Harnden Jr. develops a both a static electronic
photoflash assembly (1968) and disposable flashbulb lamp(1971)
along with Bill Kornrumpf. The array of flash bulbs removes
the need for replacing the bulb. This long plastic bar of bulbs
was popular in the 1970s and 80s. Harnden also developed precise
timing devices for the bulbs that used semiconductors which
were new at the time. Schenectady,
1968William P. Kornrumpf developed the photoflash
bulb assembly and disposable flashbulb array for low cost cameras
along with John D. Harnden. Schenectady, New York
Give us feedback on this and other pages using our
by M. Whelan with additional research by Rick DeLair and Ryotaro Miyajima
"The General Electric Story" 1999. by the Hall of History, Scientific
Wikipedia.com, Scienceclarified.com, Lexicon Siemensstast: Werner von
The Siemens Forum, Munich, Germany
"Men and Volts" John Hammond. 1941
Edison Tech Center
John Harnden Jr.
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