Light Bulb

Lyspære is a word derived from Danish and Norwegian, meaning 'electric lamp' or household light. It refers to a small glass device in which electricity is converted to light, installed in a fixture or electrical cord that hangs from a ceiling or wall.

The word comprises two parts: 'lys', meaning light, and 'pære', originally from the pear-shaped fruits known in English as 'pear'. The name came from the shape of early electric lamps, which resembled that fruit. Similarly, other languages use names based on shape or function—for example, English 'bulb'.

How the incandescent bulb works

The earliest type of lyspære was the incandescent lamp. A very fine filament, usually made of a metal called tungsten, has electricity passed through it. The resistance of the filament causes it to heat up until it glows and emits light. To prevent the filament from burning up, the air is removed from inside the glass or it is filled with an inert gas such as argon or nitrogen.

Other types

As the later centuries progressed, incandescent bulbs were often replaced by types of lamps that use less electricity. These include compact fluorescent bulbs (CFL), which produce light from excited gas and a phosphorescent coating, and LED bulbs, which emit light from a semiconductor device. The term 'lyspære' is still used even when referring to these newer types, because their shape and mounting position remain the same.

Legislation and market change

Many countries, including those in the European Union, have passed laws restricting the sale of high-energy incandescent bulbs, with the aim of reducing electricity consumption. These measures accelerated the shift of LED bulbs to market dominance.