Input and Output devices

 Input and Output devices

An input is data that a computer receives. An output is data that a computer sends.

Computers only work with digital information. Any input that a computer receives must be digitised.

Often data has to be converted back to an analogue format when it's output, for example the sound from a computer's speakers.

An input device is something you connect to a computer that sends information into the computer. An output device is something you connect to a computer that has information sent to it.

List of Input Devices

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

1. 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

2. Mouse

• It is also known as a pointing device
• Using mouse we can directly click on the various icons present on the system and open up various files and programs
• A mouse comprises 3 buttons on the top and one trackball at the bottom which helps in selecting and moving the mouse around, respectively
• In case of laptops, the touchpad is given as a replacement of mouse which helps in the movement of the mouse pointer

3. 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

4. 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

5. 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

6. 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

7. Barcode Reader

• It is a kind of an optical scanner
• It can read bar codes
• A source of light is passed through a bard code, and its aspects and details are displayed on the screen

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 Devices

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

1. 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

2. Printer

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

3. 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

4. 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 lightening
• 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

5. 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
• Also known as earphones or headset