Main Parts of a Personal Computer (PC)

Main Parts of a Personal Computer

Here is a typical PC or Personal Computer system that is possibly similar to the one you are using to study this course.

 

The Central Processing Unit (Cpu)

The Central Processing Unit (CPU) is a silicon chip that is the real brain of the computer. It sits inside the system unit.

 

Input Devices

To put information into your PC you need an input device. Two of the most commonly used are shown here, the keyboard and the mouse.

 

Output Devices

Computer systems can have many different output devices. These convert computer data into a form that you can read and two of the most common are a screen and a printer.

Auxiliary Storage Devices

When you have entered information into your computer you may need to save it for future use. For this you need either a floppy disk or one of a variety of internal or external auxiliary storage devices, some of which we will described later here.

 

Four Main Components Of A Computer

You have now seen that the components of a basic personal computer system fall into four categories:

Input Device

System Unit Containing the CPU

Output Device

Auxiliary Storage Unit

 

Peripheral Devices

All of the pieces of hardware that are attached to the basic system unit and controlled by the CPU are called peripheral devices or simply peripherals.

Central Processing Unit (CPU)

What Is The CPU?

The CPU is the silicon chip which functions as the real 'brain' of the computer. The system case, which contains the computer's chips and circuits, is often incorrectly referred to as the CPU.

 

What Does The CPU Do?

The CPU is responsible for the control and execution of all the computer's operations. It accesses data from memory, carries out the intended operations and stores the result into memory.

Elements Of The CPU

For this course you only need to understand the broad concepts of the CPU's control unit, arithmetic and logic unit (ALU) and internal (register) memory.

Control Unit - The control unit is responsible for the control and timing of all the tasks being performed by the CPU. The instruction to be carried out is decoded so that the computer knows what action to take. A signal to carry out this operation is then sent out to the ALU.

Arithmetic and Logic Unit - The ALU carries out the current operation or calculation. The result from the operation is temporarily stored in a special memory location or register known as the accumulator.

Internal Memory - The Memory cells inside the CPU, called registers, are used for the temporary storage of data needed for the current operation. Values to be operated on and results obtained are stored in these registers while the operation is being carried out. Once this is completed the result is moved into the computer's main memory so that the registers can be cleared for the next operation.

Measuring The Speed Of The CPU

The speed at which the CPU operates is referred to as the clock speed and is expressed in Megahertz (Mhz).

For example: 60 Mhz = 60 million cycles per second. 400 Mhz = 400 million cycles per second.