The History of the Incandescent Light Bulb
Incandescent light bulbs are a great option for achieving warm lighting. They produce a warm glow and are inexpensive to purchase and install. However, they are also very inefficient and generate low lumens per watt.
The incandescent bulb consists of a filament (typically made from tungsten) inside a glass bulb filled with inert gases like argon and krypton. When current flows through the filament, it heats up to incandescence and emits light.
Origins
The incandescent light bulb is a versatile electrical device that has been used for over a century. Its roots can be traced back to experiments in the early 1800s. Humphry Davy, an English chemist, connected two wires to a battery and placed charcoal sticks between them, creating a glowing arc of electric current that lit up the charcoal. The lamp was functional but impractical. Throughout the 1800s, many scientists and inventors tried to create more practical versions of the light bulb. One of the most notable was Warren de la Rue, who enclosed a platinum coil inside a vacuum tube and passed an electric current through it. However, platinum is a very expensive metal that limited his design’s commercial viability.
Eventually, Joseph Wilson Swan created a carbonized paper filament that produced a more durable and long-lasting electric light bulb. Later, William D. Coolidge discovered that tungsten was a better material for making bulbs than previous sintered tungsten. He also developed a process for heating and drawing the tungsten, which made it more ductile. The resulting bulb was far more efficient and lasted longer than previous designs.
Today, incandescent light bulbs are available in a variety of shapes and sizes. They are also classified by shape and size designations, which allow consumers to easily compare one type of bulb to another.
Development of the filament
Before Edison, a number of inventors tried to make an incandescent lamp. They used a range of materials including charcoal, wood splints, paper output speed sensor and cotton. But these early attempts were rudimentary and did not last long. The basic principle of the light bulb is that an electric current passes through a filament heated to incandescence and emits visible and invisible radiation.
The first successful incandescent bulbs were made from platinum. The high melting point of this metal allows it to be operated at very high temperatures without destroying the filament. Other metals with higher melting points were also tested, but most did not last. Warren De la Rue enclosed a coiled platinum filament inside a partially evacuated tube, which helped to lengthen its lifespan. But these early bulbs were prone to rupture and implosion.
In 1879, Joseph Wilson Swan invented a carbonized paper filament that lasted several hours. This was a huge improvement on the previous designs, and led to a commercially viable light bulb. General Electric began investing more in its research laboratory to find new filaments and other improvements. William Coolidge was hired to help develop these advancements. He found that tungsten had a lower melting point and was more durable than other metals. He developed a way to heat tungsten and draw it out through heated dies of decreasing size, creating ductile tungsten wire. This improved the life of the filament and allowed the bulbs to be produced at a fraction of their original cost.
Inventors
Early researchers heated thin wires by passing electric current through them to produce light. They were not able to create bulbs that lasted long enough for practical use. Humphry Davy, who created the first electric lighting system in 1809, used a platinum strip to produce a glow. The strip glowed but did not last long and the platinum was very expensive. In 1820, Warren De la Rue enclosed a platinum coil in an evacuated glass tube and passed electricity through it. This bulb worked but it lacked a strong vacuum, which would have reduced blackening and lengthened lamp life.
By the mid-1850s, Joseph Swan had patented a carbonized paper filament and achieved a lamp that lasted more than 600 hours. However, he could not improve upon this design without a more durable filament material and a better system to create a vacuum in the bulb.
Edison, who had previously patented the stock ticker, quadruplex telegraph and phonograph, formed a team of 14 engineers and machinists to work incandescent light bulb on the bulb project in Menlo Park, NJ. He was determined to make a safe and economical incandescent lamp that would replace gas lights.
Edison succeeded where others failed due to three factors: a more effective incandescent material, the ability to create a pure vacuum in the bulb (using the Sprengel pump), and a filament material that exhibited a high resistance which promoted economically efficient power distribution.
Life expectancy
When a light bulb is turned on, it draws a surge of electric current that can damage the filament. This shortens the bulb’s lifespan, and it can also damage the glass of the lamp. To prevent this, you should only handle filament bulbs when they are at room temperature. Also, you should avoid moving them too much when they’re hot. If you do, you’ll increase the likelihood that the filament will snap. This can reduce the bulb’s lifespan by up to 50%.
The life expectancy of an incandescent light bulb is a measure of the number of hours that it can be used before it will need to be replaced. It can also be referred to as the average rated life (ARL). The ARL is determined by testing a large group of bulbs and noting when half of them have died.
Incandescent bulbs consume a lot of energy, and their long lifespans make them an inefficient choice for most homes. This type of lighting is being phased out in favor of more efficient options like LED and CFL bulbs. Unlike incandescent bulbs, CFLs are able to convert almost all of their electricity into useful light. These bulbs typically last up to 25,000 hours, but they require more wattage than incandescent bulbs. The upfront cost of these bulbs is higher, but they can save you money in the long run.