INPUT AND OUTPUT COMPUTER DEVICES

The functioning of a computer system is based on the combined usage of both input and output devices. Using an input device we can give instructions to the computer to perform an action and the device reverts to our action through an output device. 

Input Device 

A piece of equipment/hardware which helps us enter data into a computer is called an input device. For example keyboard, mouse, etc. 

Output Device 

A piece of equipment/hardware which gives out the result of the entered input, once it is processed (i.e. converts data from machine language to a human-understandable language), is called an output device. For example printer, monitor, etc

List of Input Devices

Given below is the list of the most common input devices along with brief information about each of them.

Keyboard

A simple device comprising keys and each key denotes either an alphabet, number or number commands which can be given to a computer for various actions to be performed

• It has a modified version of typewriter keys
• The keyboard is an essential input device and computer and laptops both use keyboards to give commands to the computer

Mouse

It is also known as a pointing device

A mouse comprises 3 buttons on the top and one trackball at the bottom which helps in selecting and moving the mouse around, respectively

• Using mouse we can directly click on the various icons present on the system and open up various files and programs
• In case of laptops, the touchpad is given as a replacement of the mouse which helps in the movement of the mouse pointer

Joy Stick

It is a device which comprises a stick which is attached at an angle to the base so that it can be moved and controlled

• Mostly used to control the movement in video games
• Apart from a computer system, a joystick is also used in the cockpit of an aeroplane, wheelchairs, cranes, trucks, etc. to operate them well

Light Pen

It is a wand-like looking device which can directly be moved over the device’s screen

• It is light-sensitive
• Used in conjunction with computer’s cathode ray tube

Microphone

Using a microphone, sound can be stored in a device in its digital form

• It converts sound into an electrical signal
• To record or reproduce a sound created using a microphone, it needs to be connected with an amplifier

Scanner

This device can scan images or text and convert it into a digital signal

When we place any piece of a document on a scanner, it converts it into a digital signal and displays it on the computer screen

Barcode Reader

A source of light is passed through a bar code, and its aspects and details are displayed on the screen

• It is a kind of an optical scanner
• It can read bar codes

Web Cam

This is a very basic video camera used to feed live video into a computer. The video data from a web cam is low quality compared to a full video camera.

Video Camera

Like a digital camera, most video cameras do not directly input data into a computer – the captured movies are stored on video-tape or  memory cards and later transferred to a  computer.

Touch Screen

Is a special kind of screen which is sensitive to touch. Touching with their finger the desired icon or menu item displayed on the screen

Other Input Devices

• Tracker ball
• Touch sensitive pad
• Graphics tablets (Digitizers)
• Optical Character Readers
• Optical Character Recognition (OCR)
• Magnetic Ink Character Reader (MICR)
• Optical Mark Readers and Optical Mark
• Recognition (OMR)
• Punched CardK
• imball tag
• Voice Recognition e.g. Microphone
• Electronic Point of Sale (EPOS)
• Electronic Fund Transfer at Point of sale(EFTPOS)
• Video digitizer 
• Digital Camera
• Touch tone Telephones

All the devices mentioned above are the most commonly used input devices. Several other such types of equipment are used in different fields which can be counted as an input device

List of Output Device

The commonly used output devices have been listed below with a brief summary of what their function is and how they can be used.

Monitor

The device which displays all the icons, text, images, etc. over a screen is called the Monitor

• When we ask the computer to perform an action, the result of that action is displayed on the monitor
• Various types of monitors have also been developed over the years

Types of Monitor

There are two types of monitor:

1. Cathode Ray Tube monitor (CRT) 

Is Just like a television set. CRT monitors are 

heavy and use more electrical power than flat panel displays, but they are preferred by some graphic artists for their accurate color rendition, and preferred by some gamers for faster response to rapidly changing graphics

1. Flat Panel/LCD (Liquid crystal display) monitor.

Flat-screen monitors are light in weight and they take up very little desk space. Have little energy consumption and have liquid 

that reduce the intensity of contacted rays. Monitor screen size is measured diagonally across the screen, in inches.

Printer

A device which makes a copy of the pictorial or textual content, usually over a paper is called a printer

• or example, an author types the entire book on his/her computer and later gets a print out of it, which is in the form of paper and is later published
• Multiple types of printers are also available in the market, which can serve different purposes

Types of Printer

1. Dot matrix printers. Quality is poor, the printers are noisy
2. Ink Jet Printer. Its Cheap, high-quality, full-color printing. Also it is perfect for photographs. Ink-jet printers are very quiet in use.
3. Laser Printer. Laser printers are very complex devices, and thus expensive to buy. However they are very cheap to use. It is very fast in printing compared to other printers (just a few seconds per page).

Speakers

A device through which we can listen to a sound as an outcome of what we command a computer to do is called a speaker

• Speakers are attached with a computer system and also are a hardware device which can be attached separately
• With the advancement in technology, speakers are now available which are wireless and can be connected using BlueTooth or other applications

Projector

An optical device which presents an image or moving images onto a projection screen is called a projector

• Most commonly these projectors are used in auditoriums and movie theatres for the display of the videos or lighting
• If a projector is connected to a computer, then the image/video displayed on the screen is the same as the one displayed on the computer screen

Headphones

They perform the same function as a speaker, the only difference is the frequency of sound

Using speakers, the sound can be heard over a larger area and using headphones, the sound is only audible to the person using them