The Central Processing Unit

All you need to know

What is the central processing unit?

The processor is the brains of the computer and deals with all the movement of data and any calculations to be carried out.

Why do computers need a CPU?

Computers can carry out instructions very quickly because the CPU can process billions of instructions every second, although it only does one at a time.

What is the processor made up from?

What are the roles of the processor parts?

The Control Unit (CU)

The job of the control unit is to fetch instructions from the main memory. It will then try to understand these instructions and carry them out.

To simplify the control unit is responsible for running programs that are loaded into main memory.

The Arithmetic and Logic Unit (ALU)

Carries out computers arithmetical functions such as addition, subtraction, multiplication etc

Carries out the computers logical functions such as comparing values using IF, AND, >,<, WHILE


Registers are small temporary memory locations located on the processor.

They are used to store the data for the current instruction being processed.