Incandescent light bulb
An incandescent light bulb is a type of electric light that produces light through a heated filament within a glass enclosure. When electricity flows through the filament, it heats up and emits visible light, a phenomenon known as incandescence. The concept of this lighting technology began to take shape in the early 1800s, with various inventors, including Thomas Edison and Joseph Swan, contributing to its development. Edison is often credited with creating the first commercially viable incandescent bulb, making significant improvements in filament durability and bulb design, which allowed for longer-lasting use.
Throughout the 20th century, incandescent bulbs became the predominant source of artificial light in homes and businesses. However, they are known for their low energy efficiency, producing more heat than light. This inefficiency has prompted the introduction of alternative lighting technologies, such as fluorescent bulbs and light-emitting diodes (LEDs). In the United States, regulatory efforts have aimed to phase out incandescent bulbs due to their energy consumption, leading to a gradual shift towards more efficient lighting solutions. Despite this, incandescent bulbs continue to hold a place in many households, reflecting a balance between tradition and modern energy concerns.
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Subject Terms
Incandescent light bulb
An incandescent light bulb is a glass vessel containing a filament. When connected to a source of electricity, power runs through the filament, heating it until it glows. The brightly glowing filament can then provide lighting for any required tasks. The word incandescent refers to thermal radiation—basically, the process by which heat creates light.
Inventors began experimenting with light bulbs about 1800 and dozens of scientists contributed discoveries and insights. Credit for the first commercially practical incandescent light bulb generally goes to American inventor Thomas Edison. Incandescent light bulbs provided the main source of lighting throughout the twentieth century, after which more-efficient forms of lighting began to overtake them.
History
Prior to the invention of the electric light bulb, people had few options when it came to lighting. During the daytime, the sun was the main source of light. At night, people relied on the ancient power of fire. Fireplaces, candles, and lanterns provided light in homes. Outdoors, apart from moonlight, gas-fueled streetlamps were the best option for lighting.
All these options required fuel for burning and created smoke that could cause health and environmental problems. Fire light was limited in strength, and in cold, windy, or rainy conditions might be impossible to start or were quickly extinguished. Meanwhile, the use of fire carried the inherent risk of mishap.
Many inventors began to seek a more efficient and reliable alternative to fire light. The long quest for the electric lightbulb started about 1800 due to rapid advances in electricity generation. Early experimenters realized that metal wires that conducted electricity grew so hot that they glowed. This emission of brightness, however faint, proved that the controlled flow of electricity could someday provide a form of lighting.
Many scientists began working with the concept. Among the first and most notable of these was Humphry Davy, an inventor who likely created the first electric lamp in 1802. Known as an electric arc lamp, this device generated light by passing an electric current between two rods. Although this original creation was not reliable for creating sustained light, it helped to inspire future generations of engineers.
By the 1840s, inventors such as Warren de la Rue had begun encasing their electrified wires within transparent glass bulbs to help protect the delicate parts, better distribute light, and protect users from burns. Early creations of these models used rare and expensive materials unsuited for widespread use. Later creations found more economical means. A few important innovators included Americans William Sawyer and Albon Man.
In 1850, English chemist Joseph Swan began using cheaper materials, such as filaments made of carbonized paper, and strengthening them by encasing them in partial vacuum tubes. American inventor Thomas Edison was deeply invested in the quest for electric lighting by the 1870s. He attempted to improve upon Swan’s design. After a legal conflict between the inventors, Swan and Edison ultimately became partners in the light bulb business.
Overview
The idea of the incandescent light bulb developed throughout the 1800s thanks to the work of dozens of inventors, chemists, engineers, and others. Several scientists created similar inventions that proved the functionality of their ideas. However, all of the early designs had major limitations. For many, filament life was brief. Others required platinum or other very expensive metals. Other bulbs had a tendency to create a black burn mark on the inside of the bulbs, thus reducing their clarity.
Edison was generally recognized as the creator of the first practical incandescent bulb. His bulbs were the first to meet reasonable standards for long-lasting duration, light creation, safety, durability, and affordability. In addition, his keen business sense allowed his offerings to quickly assume a prominent place in the lighting market, assuring his success.
Edison’s light bulb surpassed Swan’s in a few critical respects. First, Edison was able to achieve a pure vacuum inside his light bulbs, whereas Swan had only reached a partial vacuum. Another major innovation was the filament. Edison famously experimented with hundreds of different materials, testing their ability to conduct electricity and create light without burning out or breaking. Some of his greatest early successes came with carbonized sewing threads, a type of heavy art paper called Bristol board, and bamboo imported from Japan.
Edison patented his first bulbs in 1879 and 1880. His first models lasted 14.5 hours, a drastically brief time by modern standards, but impressive at the time. Later experiments increased the duration considerably, with his bamboo filaments capable of glowing for as much as 1,200 hours. The innovations continued.
By the early 1900s, Edison, his company, and many competing scientists determined that metal filaments could greatly increase light bulb lifespan. One of the first highly successful metals for this purpose was tantalum, innovated in Germany by Werner von Bolton, which became an industry standard in the first decade of the 1900s.
Shortly afterward, inventors such as William D. Coolidge, Alexander Just, and Franz (Franjo) Hanaman embraced the metal tungsten. When properly prepared, tungsten proved the best-known material for creating reliable, long-lasting bulb filaments. From its first widespread adoption in 1911, tungsten became the most common filament material for incandescent lights into modern times.
Incandescent bulbs seemed, at first, the perfect solution to lighting problems worldwide. The bulbs were relatively cheap to produce, did not create significant toxic by-products, and could work with a variety of different circuits. However, the technology had inherent limitations. The main problem was energy efficiency, since about 90 percent of the electricity created heat and only about 10 percent generated light.
New generations of inventors began envisioning a world with more efficient forms of lighting. Among the innovations that appeared in the twentieth century were fluorescent bulbs and, later, light-emitting diodes (LEDs). These technologies greatly increased the energy efficiency of creating large amounts of light with electrical power.
Over time, energy-minded reformers began to call for the seemingly ubiquitous incandescent bulbs to be replaced with newer technologies. In the United States, the Energy Independence and Security Act of 2007 made official a nationwide phase-out of incandescent light bulbs. Passed by Congress and signed by President George W. Bush, the act increased efficiency requirements for light bulbs, among other technologies, and instituted a ban on low-performing types of bulb.
In 2019, President Donald Trump overturned major parts of the act and allowed “general service” incandescent bulbs to remain in use. Many critics decried the move as damaging to the environment, but the Trump Administration said the move allowed American consumers more choices and less government restriction. The phase-out is likely to continue organically as many consumers shift to more efficient technologies. In 2016, for example, just 6 percent of ordinary pear-shaped bulbs in US homes were traditional incandescent light bulbs.
Bibliography
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