Incandescent Light Bulb Diagram | New Topic

In this note, we are going to know about the Incandescent Light Bulb Diagram and function of each part or component in the incandescent bulb. Welcome to Poly Notes Hub, a leading destination for polytechnic or degree engineering notes.

Author Name: Arun Paul.

Introduction

An incandescent light bulb is an electric light that works by heating a tungsten filament until it glows. When an electric current travels through a filament, it heats up sufficiently to create visible light owing to incandescence. The bulb is filled with an inert gas, such as argon or nitrogen, to keep the filament from oxidizing and extend its life.

Applications of Incandescent Light Bulb

• Household lighting
• Decorative lamps and chandeliers
• Flashlights
• Automobile headlights and tail lamps
• Signal and indicator lights
• Heat lamps and incubators
• Photography and studio lighting

Available Power Rating of Incandescent Bulb

Incandescent bulbs come in a variety of power ratings based on their brightness and usage. Typical power ratings include –

• 15 Watts – Used for decorative or indicator lights.
• 25 Watts – Suitable for night lamps and small decorative fixtures.
• 40 Watts – Common for domestic lighting in small rooms or lamps.
• 60 Watts – Standard household lighting, often used in living rooms and bedrooms.
• 75 Watts – Used in larger spaces requiring brighter illumination.
• 100 Watts – Used for bright lighting in halls, outdoor fixtures, or workshops.
• 150 Watts and above – Used in industrial, commercial, or outdoor lighting applications.

The brightness of an incandescent bulb grows with wattage, but so does its energy consumption and heat output. That is why modern lighting systems are turning to LED and CFL bulbs, which provide the same brightness at much lower wattages.

Incandescent Light Bulb Diagram (Function of Each Component)

• Glass: The exterior glass bulb encloses all of the interior components. It shields the filament and other components from external damage and avoids filament oxidation by sealing the bulb from air.
• Gas Filling: The bulb is filled with inert gases like argon or nitrogen. These gasses reduce the tungsten filament’s evaporation rate, increasing the bulb’s efficiency and lifespan.
• Tungsten Filament: The tungsten filament is the primary light-emitting component. When an electric current travels through it, the filament warms up to approximately 2500-3000°C and glows, providing light via incandescence.
• Support Wire: These are thin metal wires that hold the filament in place, ensuring that it remains properly aligned and does not sag or vibrate while heated.
• Dumet Wire: Dumet wire is a particular sort of wire that seals the glass and connects the lead wire to the filament. It creates an airtight seal between the glass bulb and the metal conductor, preventing gas leakage.
• Cap: The metal cap, also known as the base, links the bulb to the lamp holder or socket. It offers both electrical connection and mechanical support. The cap includes two contact points: one for the live connection and one for the neutral.
• Lead Wire: These wires connect the filament to the external electrical circuit via the base. They transport current to and from the filament, causing it to glow as electricity flows.
• Exhaust Tube: The exhaust tube is used in the production process to remove air from the bulb and replace it with inert gas. It is sealed after filling to keep the internal atmosphere stable.