Hi everyone! Now, we will learn about one of the most common types of artificial lighting — the Tungsten Filament Lamp, also known as the GLS bulb.

First, let’s break down the name.

‘Tungsten’ refers to the material used for the filament inside the bulb, and ‘GLS’ stands for General Lighting Service — meaning it’s a general-purpose lamp used for everyday lighting.

1. What is a Tungsten Filament Lamp?

A tungsten filament lamp is a traditional incandescent light bulb where an electric current passes through a thin tungsten wire filament. The filament heats up to a very high temperature and produces light through incandescence — basically glowing from heat.

2. How Does It Work?

When electricity flows through the tungsten filament, its resistance causes it to heat up. Because tungsten has a very high melting point (around 3422 °C), the filament can get extremely hot without melting, glowing brightly and producing visible light.

Inside the bulb is usually a vacuum or inert gas like argon to prevent the filament from burning out quickly.

3. Advantages of Tungsten Filament Lamps

• Simple design and easy to manufacture.

• Provide warm, pleasant light (around 2700 Kelvin).

• Good color rendering — colors appear natural.

• Inexpensive upfront cost.

4. Disadvantages

• Very inefficient — most energy is wasted as heat, not light.

• Shorter lifespan compared to modern lighting like LEDs or fluorescents.

• Generates a lot of heat, which can be a safety concern or add to cooling costs.

• Being phased out in many countries due to energy efficiency regulations.

5. Common Uses

Although tungsten filament lamps are less popular now, they are still used in:

• Decorative lighting (e.g., chandeliers, vintage lamps).

• Some specialized applications requiring warm light.

• Situations where dimmable and instant-on lighting is needed.

6. Quick Recap / Questions

Let’s quickly recap: What makes tungsten filament lamps glow?

Yes, the filament heats up due to electric current!

Closing

Tungsten filament lamps paved the way for modern lighting. Understanding how they work helps us appreciate advances in lighting technology. Next time, we will explore tungsten halogen lamps and how they improved upon the standard incandescent design.