What is an Incandescent Light Bulb?
An incandescent light bulb is a type of electric lamp that produces light by heating a filament to high temperatures. The filament is contained in a glass bulb and the heat radiates into the surrounding air to produce light.
Several inventors worked on this idea before Thomas Edison succeeded in creating a bulb that would last for more than 14 hours. This was a major breakthrough.
Origin
The history of the light bulb is long and varied. Although rudimentary incandescent lights existed before 1835, it was American inventor Thomas Edison who produced the first commercially practical light bulb that resembles those we use today. He outstripped other inventors because of his ability to combine several key elements into a workable lamp design: an effective incandescent material, a more efficient way to eliminate air from the bulb using the Sprengel pump and a filament that could be affixed to a glass bulb with minimal resistance.
In the 1800s, Humphrey Davy created a light source by passing electric current through output speed sensor a strip of platinum which caused it to glow. This was the first recorded incandescent light but it was not a practical power source because the platinum strips combusted and blackened on top which blocked light output. British chemist and physicist Joseph Swan began working on the light bulb three decades earlier and was granted a patent in 1878 for his carbon filament incandescent lamp which utilized a glass bulb, a partial vacuum and powdered charcoal to emit light. His invention, however, had two major flaws — a short lifespan and the inability to produce enough heat using a high-power battery.
Warren de la Rue was able to create a workable light bulb in 1840 by enclosing a coiled platinum filament inside a partially evacuated tube and channeling electricity through it. The metal’s high melting point enabled him to use it at very hot temperatures and the vacuum minimized gas molecules from reacting with the heated metal which prolonged its life.
Luminous Efficiency
Incandescent bulbs use electricity to heat a filament wire until it glows. The resulting light is emitted by the hot filament as infrared radiation and reflected by the surrounding glass. The visible light consists of a broad spectrum that produces a warm, cozy feel while faithfully rendering colors in an environment.
Despite the glowing reputation of incandescent light bulbs, they are notoriously inefficient. About 95 percent of their energy goes to generating waste heat instead of light, and that’s why virtually all forward-thinking nations have started phasing out this type of light bulb.
The luminous efficiency (a light bulb’s ability to convert electrical power into useful light) of an incandescent light bulb depends primarily on the temperature and diameter of the filament, the orientation of the gas layer that surrounds the filament, and whether the bulb is evacuated. Bulb size also influences luminous efficiency, with larger bulbs producing more light than smaller ones.
Some improvements have been made to the standard incandescent light bulb, including the development of more efficient filaments and the use of a sleeve or shell to contain the filament. A major improvement came in 1911 when William Coolidge figured out how to make tungsten, an expensive metal, into a workable filament. He smelted the tungsten and then drew it through heated dies of decreasing diameter, making a thicker, more durable filament that greatly improved the light bulb’s luminous efficacy.
Lifespan
Despite the fact that some of them last longer than others, most standard incandescent bulbs have short lifespans compared to other bulb types. They can burn up to a few thousand hours before reaching their end-of-life. During this time, they will produce less light than they initially did.
The bulbs will still function, but they will not emit as much heat. In some cases, you will need to replace them in order to keep your home or business lit. However, you can prolong the lifespan of your light bulbs by not switching them on and off frequently. This reduces the number of times the filament is heated and cooled.
In addition, you should also consider using higher quality light bulbs if you want to extend their lifespans. The manufacturers of these bulbs use better materials to build their products, which allows them to stand up to more frequent use.
Some of the early bulbs were not very durable, though, due to their poor construction. Some were prone to cracking or bursting, and others simply burned out after one use.
In an effort to solve this problem, Edison and other inventors worked on a new type of filament. The tungsten filament they developed lasted longer and produced more light than carbon filaments. These improvements led to the development of modern incandescent bulbs.
Energy Efficiency
An incandescent light bulb uses electricity to heat a filament until it glows. The atoms in the filament are vibrated by the electric current and emit thermal radiation that makes the bulb glow. In a standard 60- or 100-watt bulb, the temperature of the filament is over 2,000o C or 3,600o F. This is high enough to produce a lot of visible light, but not so hot that the bulbs are dangerous to touch.
In addition to producing light, incandescent bulbs also produce heat, which increases the load on a building’s air conditioning system. Because they waste so much energy as heat, they are one of the least efficient types of lighting available.
The first incandescent bulbs didn’t last long, but many inventors worked to improve them. Thomas incandescent light bulb Edison had the most success, with bulbs that lasted longer than previous inventions. In 1879 he developed the carbon filament and oxygen-less enclosure, which made his bulbs last fourteen hours or more.
Other inventors made improvements like filling the bulbs with an inert gas, which helped them last longer and produce more light. Today, most practical incandescent light bulbs can provide 1,000 hours of use. New rules phasing out the sale of less efficient bulbs will save consumers $3 billion per year on utility bills and prevent 222 million tons of climate-warming carbon pollution over 30 years.
