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📘 Bars encode a number in widths

Bars encode a number in widths

lessons

~10 min

to learn

🔬 Science

subject

Adults

level

Start the course →

What you’ll learn

The pattern
Illumination
The detector
Edges
Symbology
Checks
Quiet zones
The lookup
Two dimensions
The loop

Questions this course answers

What does a retail barcode usually encode?

The barcode carries a key such as a GTIN for lookup.

What does a photodiode measure?

Dark and light regions create changing optical reflections.

What is a quiet zone?

Clear margins help locate symbol boundaries.

What does a check digit do?

Recomputing it can reject an incorrectly decoded number.

How do 2D codes differ from linear codes?

Two-dimensional symbols use rows and columns of visual modules.

Grounded in trusted sources

[object Object]
[object Object]
[object Object]
[object Object]

Every Wunder lesson is built from real, reputable sources — never invented.

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Wunder is a personalized learn-anything platform — tell it any topic and it builds a beautiful, fact-checked course in minutes, with narration, a knowledge check, and a college-style University track.

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