CPU (Central Processing Unit)
- It's a microprocessor chip developed by Intel, AMD or any other company.
- CPU speed depends upon the clock frequency, higher the clock frequency more number of instructions can be executed per second.
- Clock frequency is measured in MHz or GHz.
- CPU word size is the largest number of bits that can be handled by CPU in one clock cycle. It is either 8, 16, 32, 64 or 128 bit.
- This word size value determines number of bit processor i.e. 8-bit processor, 16-bit processor, 32 bit processor etc.
- CPU performance also depends upon the RAM, bus speed and cache size as well.
- Called as heart of the computer.
- CPU consists of three basic units: control unit, Arithmetic Logical Unit (ALU) and memory unit.
- Input is given through the input devices to CPU.
- Control unit controls communication within ALU and memory unit.
- Decides which circuit is to be activated.
- For reading instruction it uses Fetch-execute mechanism.
- Control unit gets instruction from memory.
- Control unit decides what to do of that instruction and transfers it to the ALU.
- ALU performs various arithmetic operations like addition, subtraction, multiplication, division and logical operations like AND, OR, NOT, NAND etc. on that instruction.
- Results of ALU are stored in the memory or resistor for its further operations.
- After completing the instruction, stored results are passed to the output devices.
- To synchronize all these operations CPU uses its own system clock.
What it does?
- Executes stored instructions called as program.
- Tells rest of the computer system what to do.
- Executes arithmetic calculation and data manipulation.
- Holds data and instruction which are in the current use.
- Responsible for storing and retrieving information on disks and other media.
All CPU’s have different numbers of pins at the bottom side, which can be easily bend or broken while installing onto the motherboard, so it must be done carefully.