Understanding character sets. In a computer, Every character has to have its own unique code, it has to be recognized. This code is in the form of a binary number. When you have a complete set of characters, these are called character sets. And there are some standard sets that used so that global communication can take place. For your GCSE, you need to be aware of two character sets.
The first is ASCII two, which started out using seven bits to represent characters, but has been extended to use eight bits so more characters can be recognized. The amount of bits you use determines how many characters can be presented. As the more bits that you have, the more numbers you can represent. If you only have one bit for example, you can only represent two different numbers zero and one. If you have two bits, you can represent four different numbers 012 237 bits allows you to represent 128 different numbers and therefore 128 different characters. It is important to note that in character sets, upper and lowercase letters need to be represented as different characters.
And space also needs to be represented as a character. Character codes for letters and digits are sequential. This means that if you know one character code, you can work out others. As can be seen in the table. The character code for uppercase a is 1000001 in seven bit binary, and this is the decimal value 65. The character code for uppercase B in seven bit binary is 1000010, which is 66 in decimal.
You should make a note of these two as you will use them on the next slide to figure out some other character codes. Use the information from the previous slide to work out the seven bit binary character code. For these questions. All the letters are uppercase. Pause the video whilst you have a go. Using the information, we can see that the character code for uppercase e 69.
The character code for uppercase P is 80. And the character code for uppercase y is 89. ASCII to code only covers a limited amount of characters used in the English language. There are of course many other languages around the world, and we need to be able to communicate across these different languages. Unicode is a global standard set of character codes that is trying to incorporate all characters using all different languages across the world. At present, it has 136,755 characters within it set and uses up 32 bits to represent them