Hardware parts of Computer System

Hardware parts of Computer system :-

The main hardware parts of a Computer system are Input Device, Central Processing Unit (CPU) and Output Device.

Input Device :- An information system can not do anything until we give it some information to process. Input devices transfer data into a computerised information system so that it can be processed.

An Input device transfers data from the outside world into a computer. There are two different categories of input device. They are - Manual Input devices and Direct Data Entry devices.

Manual Input Devices :- With a manual input device the user must enter data into the computer manually. Eg - Keyboard, Pointing Device (Mouse, Light Pen, Touch Screen, Joystick), Graphics Tablet, Scanner etc.

Keyboard :- Almost all Computers are supplied with a Keyboard.
A keyboard has over 100+ keys on it. When we press a key a number code is sent to the computer to tell it which key we have pressed.
The keys are arranged in Main keyboard, Function keys, Direction keys and Numeric keypad. The general layout of keys is called QWERTY because Q,W,E,R,T,Y are in the order in which the letters occur on the top row of the keyboard.

Mouse :- A mouse is the most common pointing device. When we move the mouse across the mouse pad the ball underneath rolls and a small arrow called a mouse pointer follows the movement on the computer screen. Buttons on the mouse can be clicked or double-clicked to perform tasks, like to select an icon on the screen or to open the selected documents.

There are new mouse that don't have a ball. They use a laser to sense the motion of the mouse which is known as optical mouse.

Joystick :- Joysticks are used to play computer games. We can move a standard Joystick in any one of eight directions. The Joysticks tells the Computer in Which direction it is being pulled and computer uses this information to move anything (eg - to move a spaceship on screen). A Joystick may also have several buttons which can be pressed to trigger action such as firing a missile.

Light Pen :- A light pen is a special pen which can be pointed at any computer monitor. When the pen is pointed at the screen the computer can work out where the pen is pointing. Light pen can be used to draw on the screen or to select option from menues presented on the screen.

Touch Screen :- These screens do a similar job to the mouse. A grid of light beams or fine wires criss-cross the computer screen. When we touch the Screen the computer senses where we have pressed. It is more expensive and it is an alternative option of mouse. It can be used to choose options which are displayed on the screen.

Scanner :- A scanner can be used to input printed images such as photographs or pages of text directly into the computer.

Graphics Tablet :- Graphics tablets are use mainly by professional graphics designer. Using a graphics tablet a designer can produce much more accurate drawings on the screen than a mouse. A graphics tablet consists of a flot pad, called the tablet, on which the user draws with a special pen called stylus. As the user draw on the pad the image is created on the screen.

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