hõõgniiti

Hõõgniit, also known as a filament, is a crucial component in incandescent light bulbs. It is a thin wire, typically made of tungsten due to its high melting point and resistance to evaporation, that heats up when an electric current passes through it. This heating process causes the filament to emit light, a phenomenon known as incandescence.

The filament is usually coiled to increase its length within a small space, thereby maximizing light output and efficiency. When electricity flows through the filament, its resistance causes it to become extremely hot, reaching temperatures of around 2,700 degrees Celsius (4,900 degrees Fahrenheit). At these temperatures, the filament glows brightly, producing visible light.

The filament is housed within a glass bulb that is either evacuated or filled with an inert gas, such as argon or nitrogen. This prevents the hot filament from reacting with oxygen and burning out quickly. Over time, however, the filament does degrade through evaporation, leading to a gradual dimming of the light and eventual failure. The lifespan of an incandescent bulb is largely determined by the durability of its filament.