ASCII Encoding

Characters · Bytes · Binary

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How computers represent text as numbers — the ASCII encoding scheme, its design choices, its limits, and how Unicode and UTF-8 replaced it.

By the end, you can

Explain why a shared encoding map is necessary for storing text in a computer.
State how many codes ASCII defines and how many bits it uses per character.
Identify which ASCII codes are printable and which are control characters.
Recall the four anchor codes (A, a, '0', SPACE) and count to nearby codes from them.
Explain the single-bit relationship between uppercase and lowercase ASCII letters.
Trace the encoding pipeline: key press → ASCII number → 8-bit byte → memory.
Decode an 8-bit binary byte back to its ASCII character.
Describe why ASCII was insufficient and what problems Unicode and UTF-8 solve.
Explain what mojibake is and why it occurs.

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