Tungsten Wire Application - Incandescent Lamp

Introduction

Tungsten wire application is as tungsten filament in incandescent lamp. Tungsten wire is electrically heated to incandescent state and then incandescent lamp sends visible light by thermal radiation. Filament inside incandescent lamp is made of a very fine tungsten wire. When a normal lamp operation temperature is above 2000℃, although it cannot reach the melting point 3370℃ of the tungsten wire, such a high temperature is able to make a part of atoms evaporate from the tungsten wire surface.

Characteristic

1. The high melting point of tungsten reaches the temperature of fervorization. Temperatures of filament lighting is more than 2000℃, at such temperature, general metal have melted, and only the melting point of tungsten is over 3400℃.
2. Cheap. Cheap price benefits the spread of incandescent lamp.
3. The resistance of tungsten wire is large with poor conductivity.
4. Chemical property is stable. Strong antioxidant capacity, and tungsten wire would not react with other substances in the air, enhancing the life time of incandescent lamp.

Structure

The word "incandescence" means emission of light by a body because of its high temperature. The bulb is made of glass filled with the inert gas argon (Ar) inside. There is a very thin tungsten filament inside the bulb connected on both sides by two wires. These wires are the anode and cathode connected to a metal contact (electrical foot contact in the diagram).