hõõgniidi

Hõõgniit, also known as a filament, is a crucial component in incandescent light bulbs. It is a thin wire, typically made of tungsten, that heats up to a high temperature when an electric current passes through it. This heating process causes the filament to emit visible light, a phenomenon known as incandescence. The choice of tungsten is due to its extremely high melting point and resistance to oxidation, which allows it to withstand the intense heat without burning out quickly.

The filament is usually coiled to increase its length within a limited space, thereby enhancing its light-emitting surface area. This coiling also helps to reduce heat loss through convection. The filament is housed within a vacuum-sealed or inert gas-filled glass bulb. The vacuum or inert gas prevents the filament from oxidizing and burning up. Early incandescent bulbs often used a vacuum, but modern ones commonly use gases like argon or nitrogen to further reduce filament evaporation and extend its lifespan.

The brightness of an incandescent bulb is directly related to the temperature of the filament; higher temperatures produce more light but also shorter filament life. The lifespan of an incandescent bulb is typically measured in thousands of hours. Despite their widespread use for many decades, incandescent bulbs are gradually being replaced by more energy-efficient lighting technologies like LEDs and CFLs, due to their low energy efficiency.