Light bulb

A light bulb is a glass enclosure that produces light, and the term usually means the incandescent lamp, in which an electric current heats a thin filament until it glows. Thomas Edison patented a carbon-filament lamp in 1879, but many inventors, including Joseph Swan, worked on the idea before and alongside him.

History of the light bulb

Experiments with electric light began early. In 1802 Humphry Davy passed a current through a thin strip of platinum and made it glow, which was a first demonstration of incandescent light, though a dim and short-lived one. In 1835 James Bowman Lindsay publicly showed a constant electric light in Dundee, Scotland.

Several inventors then tried enclosed filaments. Warren de la Rue passed a current through a coiled platinum filament in a vacuum tube in 1840, and in 1841 Frederick de Moleyns received the first patent for an incandescent bulb, again using platinum in a vacuum. The cost of platinum made these designs impractical. The Russian inventor Alexander Lodygin used carbon rods in a sealed glass bulb in 1872 and obtained a patent in 1874.

Joseph Swan, an English chemist, began experiments in electric lighting in 1860. After several setbacks he made a working incandescent lamp in 1878 and patented it on 27 November 1880, under patent number 4933.

Swan’s lamp work and Edison’s overlapped in time, and each built a business around it. The Science Museum Group notes that Swan founded the Edison and Swan company on 26 October 1883, after the two sides merged rather than go to trial.

Edison patented his carbon-filament lamp on 1 November 1879. On 21 October 1879 his laboratory had produced a glowing carbonized thread that lasted for more than 14 hours, and he demonstrated the lamp in public at Menlo Park, New Jersey, on 31 December 1879.

Who invented the light bulb?

Priority is shared. The Engineering and Technology History Wiki says Edison is not the inventor of the light bulb but of the first effective and commercially viable one. Swan in Britain, Lodygin in Russia and others had working or patented lamps earlier or at the same time.

By combining forces the companies were able to suppress competition in Britain and dominate the market, with factories at Sunderland, Brimsdown and Ponders End.

The two main rivals ended up cooperating. Edison’s company threatened Swan with legal action over patents, and instead of going to court the companies merged in 1883 as the Edison and Swan United Electric Light Company, whose Ediswan bulbs dominated the British market.

How a light bulb works

In an incandescent bulb, an electric current passes through a filament, which has enough electrical resistance to heat up until it glows white-hot. The glass bulb keeps air away from the filament, because oxygen would make it burn up. Early bulbs had a vacuum inside, and later designs used inert gas.

The filament material was the central problem. Edison used carbonized material, but filaments made of tungsten, a metal with a very high melting point, replaced carbon in the early 20th century. A Science Museum Group bulb from 1910 made by the Edison and Swan company already has a tungsten filament.

Incandescent bulbs waste most of the electrical energy they receive as heat rather than light, which is the main reason they were later replaced.

Types of light bulbs

The standard incandescent bulb has a plain filament in a glass globe. Halogen bulbs are a variant that holds a small amount of halogen gas, which lets the filament run hotter and last longer. Fluorescent lamps work differently, using electricity to excite a gas in a tube coated inside with a material that glows.

Before bulbs, electric light came from arc lamps, which make light by an electric spark between two electrodes. They were bright but harsh and unsuited to homes.

The newest family is LED lighting, which uses a semiconductor chip that emits light when current passes through it. LED bulbs fit the same sockets as older bulbs but need much less electricity.

Advantages and disadvantages of incandescent and LED bulbs

Incandescent bulbs are simple, cheap to make and give a warm, steady light, and they work with ordinary dimmers. Their drawbacks are short life and high energy use, since most of the electricity becomes heat.

LED bulbs give more light for each unit of electricity and last much longer, but they cost more up front and can behave differently with older dimmers. Disposal also matters, because LED bulbs contain electronic parts that should be recycled where facilities exist.

Impact of the light bulb

Electric light made evenings brighter, cleaner and safer than lamps that burned oil or gas. It also created demand for generating stations, wiring and meters, which is part of how modern electricity networks came into being. Today those networks are described as the power grid.

Factories, shops and homes could extend their hours, and cities began to look and function differently at night. Lighting remains one of the main uses of electricity.

Uses of light bulbs today

Most new lighting is LED, and some countries have restricted the sale of the least efficient incandescent bulbs. Traditional bulbs still appear in ovens, heat lamps, theatrical fixtures and decorative lighting.

The shape of the old bulb survives as a symbol of an idea, even though the device itself is gradually being replaced by newer technology.

FAQs about the light bulb

Did Edison invent the light bulb? Not alone. He made the first effective and commercially viable one, building on earlier work by several inventors.

Who was Joseph Swan? He was an English chemist who made a working incandescent lamp in 1878 and patented it in 1880, and his company later merged with Edison’s.

Why use tungsten? It resists melting at very high temperatures, so a tungsten filament can glow brightly and last longer than carbon.

Editorially reviewed by Specialty Digest Editorial TeamLast reviewed November 4, 2026Researched and drafted with AI assistanceReport an issue