Brainlag PlusCharacter sets (ASCII and Unicode), how text size is worked out, and bitmap images with resolution, colour depth and file size.
Character sets
A character set gives every character its own binary code.
- ASCII uses 7 bits: 128 characters, enough for English letters, digits and symbols. Extended ASCII uses 8 bits for 256.
- Unicode uses up to 32 bits, so it covers the characters of almost every language, plus symbols and emoji. Its first 128 codes match ASCII.
- Codes are in order: if "A" is 65, then "B" is 66 and "G" is 71. Lower case starts at "a" = 97.
Text size in bits = number of characters × bits per character.
The rest of this lesson and its 9 practice questions are in Plus.
Screen 1 of 3, free to read.
- 9 exam-style questions, marked as you go, each with a worked solution
- Anything you get wrong is saved to your flashcards