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Let There Be Light: Incandescent & LED Lamps

Differentiate between the structure and function of incandescent bulbs and LED lamps.

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Why do bulbs 'fuse'?

Explanation of a fused bulb.

Have you ever heard someone say a bulb is "fused"? This usually means the tiny, fragile wire inside it has broken. Once broken, the path for electricity stops, and the bulb can no longer glow!
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Structure

The Incandescent Lamp

Anatomy of an incandescent torch bulb.

Many older torchlights use a small incandescent lamp to produce light. If you look closely inside the glass bulb, you will see a very thin wire in the middle.

This thin glowing wire is called the filament. When electricity passes through it, the filament gets extremely hot and glows brightly to produce light.

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Inside the Bulb

Diagram of an incandescent bulb with filament and terminals labeled.

clean scientific diagram, pastel color palette, elegant typography, precise labeling, translucent layers for cross-sections, white background, soft shadows. A cross-section of a small incandescent torch bulb. The label 'Glass bulb' points to the outer glass shell. The 'Filament' is the thin glowing wire in the middle. The 'Thick wires' are shown supporting the filament. The 'Metal case (one terminal)' is labeled around the outer bottom edge, and the 'Metal tip (other terminal)' is at the very bottom center.
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The two terminals of an incandescent lamp are the metal case and the metal tip at the base.

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Bulb Anatomy

Fill-blank on incandescent bulb parts.

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In an incandescent lamp, the thin wire inside the glass bulb that gets hot and glows is called the. This wire is supported by two thicker wires that connect to the metaland the metalat the base. These connection points form the twoof the lamp and are fixed so they do not touch each other. In contrast, a Light Emitting Diode, or, does not use a glowing wire to produce light. It has two attached wires of unequal length, where the longer wire is theterminal. The shorter wire must be connected to theterminal of the battery. Current can pass through this modern lamp in only one, so it must be connected correctly to glow.
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LEDs

Modern Light: The LED

Structure and polarity of an LED.

Many torches used today have a Light Emitting Diode (LED) instead of a traditional incandescent lamp. The biggest difference? LEDs do not have filaments inside them.

Because they lack a delicate filament, LEDs are often more durable and energy-efficient than older bulbs.

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LED vs Incandescent

Visual showing LED legs and their polarity.

clean side-by-side comparison, consistent visual treatment for both sides, same scale and style, pastel color coding to distinguish categories, elegant typography, white background, generous whitespace. On the left, a Light Emitting Diode (LED) highlighting its two wire legs. The longer leg is labeled '+ (Positive)' and the shorter leg is labeled '- (Negative)'. On the right, a small icon of an incandescent bulb with a red 'X' over its filament to signify that LEDs do not have filaments.
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LEDs have directional legs (+/-) and do not contain breakable filaments.

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matching

Match the Lamp Features

Matching exercise comparing the two lamp types.

NoteMatch the lamp feature or component to its correct property.
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Terms

Definitions