Input and Output device

Input and Output Device

Computer a machine

 A computer is an electronic machine and looks like a television with a typewriter. It runs on electricity.

Computer system

A computer has four main parts. These are the CPU, monitor, keyboard, and mouse. These four parts work together to form a computer system. A computer system can be defined as a machine that is used to generate information from the data.

The word computer is derived from two words compute which means to calculate and er means who performs the calculations.

The two basic parts of a computer system are:

  1. Hardware
  2. Software


The physical parts of a computer that you can see and touch are called hardware. CPU cabinet, monitor, mouse, keyboard, printer, etc. are some examples of hardware parts that are called devices. They are attached to the CPU by cables. Some of the other parts of the hardware are inside the CPU cabinet, for example, the hard disk, CPU chip, etc.

The hardware of a computer is further divided into three parts: input, output, and storage devices.

Input devices

The devices that are used to input data into a computer are called input devices. For example, keyboard, mouse, joystick, etc. let’s read about some common input devices.

Keyboard: a keyboard is the most common and most important input device which helps us input data into the computer. Keyboards are of different sizes. Therefore, the number of keys varies from model to model. An IBM/PC keyboard has 84 keys. Now, a window keyboard has 104 keys or 108 keys.

Mouse: A mouse is also known as a pointing device. It can be used to control the position of the cursor on the screen and to input commands into the computer. But it cannot be used to enter text into the computer.

Trackball: A trackball is an input device that is mostly used in a notebook or a laptop, in place of a mouse. By moving our fingers on the ball, we can move the cursor of the mouse.     


Scanner: A scanner is used to transform a printed copy, a drawing, or a document into a digital file. This file can easily be edited on a computer. A scanner can be connected to a computer using many different interfaces. Nowadays, it is most commonly connected to a computer with the help of a USB cable.

Web camera: A web camera (webcam for short) is a digital camera that is connected to a computer. It is used to share pictures and have live chats with friends and relatives using the internet. Always remember, when you make any image available to other using your webcam, it will remain on the internet forever.

Light pen: A light pen is a pointing device that is quite like a pen. It is used to select a displayed menu item or draw pictures on the monitor. it looks like a pen that can be used on a special pad. Whatever you write on this pad, can be seen on the monitor.

Joystick: A joystick is also a pointing device that is used to move the position of the cursor. The functions of the joystick and mouse are quite similar. The joystick can be moved in all four directions. It is mainly used in computer Aided Designing (CAD) and playing computer games.

Microphone: A microphone is used to input sound which is then stored in a digital form. It is used for various applications such as adding sound to a multimedia presentation or mixing music.

Output devices

The device that displays information and the result of processed input data are called output devices. For example, monitor, printer, etc.

Monitor: A monitor is an output device. It looks like a television screen. It is used to display whatever we type or draw, as well as the results of the inputs. It also displays the movement of a mouse pointer. It is also called VDU (Visual Display Unit). The information that we see on the monitor is called soft copy. There are two common types of modern computer monitors – cathode ray tubes and flat-panel screens.

Printers: A printer prints the output, that you see on the computer screen, on paper which is called a hard copy. The sends the image (data) to the printer. It then physically recreates the image, usually on paper. There are three types of computer printers- inkjet, LaserJet, and dot matrix.

Speakers: A speaker is a hardware device that connects to a computer to produce sound. A computer speaker is used to produce the sound created by the computer’s sound card.

Headphones: The headphones give out the sound output that is produced from a computer. They are similar to speakers; except they are worn on the ears. So, only a single person can hear the output at the same time.      

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