Understanding Tungsten Filament: Why It Is Used In Light Bulbs

Have you ever noticed the small, thin wire that holds up the incandescent light bulb, supported by two larger wires? This wire is known as a filament, and it is made from tungsten. But why do we use tungsten as a filament? What properties make it a reliable and efficient light source? This article will explore why tungsten is used as a filament, its properties, and its advantages and disadvantages.

This Story also Contains

1. Properties Of Tungsten
2. How Tungsten Filaments Work
3. Advantages of Tungsten Filaments

Properties Of Tungsten

With an atomic weight of 74 and the chemical symbol W, tungsten is a metallic element. It is a metal that is dense, hard, and very strong and has a variety of special qualities that make it the perfect substance for use in electric lights.

The high melting point of tungsten is one of the main characteristics that make it perfect for use in electric bulbs. With a melting point of 3,422 degrees Celsius, tungsten has the highest melting point of any metal (6,191 degrees Fahrenheit). The tungsten filament of an electric bulb can function at extremely high temperatures without fast burning out thanks to this high melting point. The tungsten filament heats up and emits light when an electric current is run across it. The filament may be heated up to several thousand degrees Celsius without melting thanks to it’s high melting point.

The ductility of tungsten is another crucial characteristic. Due to its high ductility, tungsten may be pulled into extremely fine wires without cracking. Due to this characteristic, tungsten may be made into the extremely thin filaments used in electric bulbs. The tungsten filament heats up quickly and emits light as a result of its high resistance to electrical current.

Tungsten has a high melting point, is ductile, and has a low vapour pressure, which makes it difficult to evaporate. Tungsten filaments have a longer lifespan than filaments produced of other materials due to this characteristic.

Overall, tungsten is the perfect material for use in electric lights due to its distinctive mix of high melting point, ductility, and low vapour pressure.

Also Read - Explore The Fascinating World of Black Holes: Formation, Properties, and Impact on the Universe

How Tungsten Filaments Work

When an electric current passes through the tungsten filament in an electric bulb, the resistance of the filament to the flow of the electric current causes it to heat up. The filament becomes so hot that it begins to emit light, creating the bright glow we see in incandescent light bulbs. This process is known as incandescence.

By drawing the tungsten into a lengthy, thin wire, a procedure known as wire drawing creates the tungsten filament. To eliminate any impurities, the wire is then twisted into a coil and heated in a vacuum. Then, the highly-purified tungsten wire is heated in a furnace to a high temperature, which causes it to anneal and increase in ductility. The wire is then coiled tightly and put into a bulb. To prevent the filament from oxidising and burning out too soon, the bulb is next evacuated, meaning that all of the air is removed from it. It is then replaced with an inert gas, such as argon or nitrogen.

Since the filaments must be both thin and robust enough to endure the high heat and pressures of use in an electric bulb, making fine tungsten filaments for light bulbs needs an exceptionally high level of precision. The diameter of the wire is decreased and its length is increased throughout the wire drawing process by dragging the tungsten through a series of dies with progressively smaller holes. Until the wire achieves the desired thickness, which may only be a few micrometres, the procedure is repeated. The resulting wire is next heated, twisted into a coil, and treated as previously mentioned.

Advantages of Tungsten Filaments

• Brightness: Tungsten filaments produce a bright, warm light that closely resembles natural sunlight. This makes them ideal for use in homes, offices, classrooms and other settings where bright and natural lighting is desired.

• Longevity: Tungsten filaments have a longer lifespan than filaments made of other materials. This is due to their high melting point, which allows them to operate at extremely high temperatures without burning out quickly.

• Cost-effective: Tungsten filaments are relatively inexpensive to produce and can be mass-produced at a low cost. This makes them a cost-effective option for lighting applications.

• Energy-efficient: Tungsten filaments are not as energy-efficient as other lighting technologies, such as LED and fluorescent bulbs, but they are still more energy-efficient than older incandescent bulbs.

Disadvantages of Tungsten Filaments

• Environmental impact: Disposing of used tungsten filament bulbs can have a negative impact on the environment. Tungsten is a non-renewable resource and the bulbs cannot be recycled in the same way that LED and fluorescent bulbs can.

• Heat generation: Tungsten filaments generate a significant amount of heat when they are in use. This can make them less ideal for use in certain settings, such as in rooms with poor ventilation.

• Low efficiency: Tungsten filaments have a lower efficiency compared to other lighting technologies, such as LEDs and fluorescent bulbs. They convert only a small fraction of the electrical energy into light, with the rest being wasted as heat.

• Limited versatility: Tungsten filaments are primarily used for lighting applications, making them less versatile compared to other materials. They cannot be used in other electronic components like transistors, capacitors or semiconductors.

Also Read - Solve The Travelling Salesman Problem With Graph Theory