The present scenario is fully occupied with computer........So, Let us know some basics about it !!!

INPUT DEVICES 

An Input device is a piece of computer hardware equipment used to provide data and control signals to an information processing system such as a computer or information appliance. 

Keyboard :-

A keyboard is a typewriter-style device which uses an arrangement of buttons or keys to act as a mechanical lever or electronic switch. 

Mouse :-

A mouse is an input device that is most often used with a personal computer. Moving a mouse along a flat surface can move the on-screen cursor to different items on the screen. Items can be moved or selected by pressing the mouse buttons (called clicking).

Scanner :-

A scanner is a device that captures images from photographic prints, posters, magazine pages, and similar sources for computer editing and display. Scanners come in hand-held, feed-in, and flatbed types and for scanning black-and-white only, or color.

Webcam:-

A webcam is a video camera that feeds or streams its image in real time to or through a computer to computer network. When "captured" by the computer, the video stream may be saved, viewed or sent on to other networks via systems such as the internet, and email as an attachment. 

Joystick :-

In computers, a joystick is a cursor control device used in computer games and assistive technology . 

Barcode reader :-

A barcode reader or barcode scanner is an electronic device that can read and output printed barcodes to a computer. Like a flatbed scanner, it consists of a light source, a lens and a light sensor translating optical impulses into electrical ones.

Graphics Tablet :- 

A graphics tablet  is a computer input device that enables a user to hand-draw images, animations and graphics, with a special pen-like stylus, similar to the way a person draws images with a pencil and paper

Microphone :-

Microphone is an input device to input sound that is then stored in digital form. The microphone is used for various applications like adding sound to a multimedia presentation or for mixing music

An Output device is any device used to send data from a computer to another device or user. Most computer data output that is meant for humans is in the form of audio or video.

OUTPUT DEVICES 

An Input device is a piece of computer hardware equipment used to provide data and control signals to an information processing system such as a computer or information appliance.  

Monitor :-

Monitors, commonly called as Visual Display Unit (VDU), are the main output device of a computer. It forms images from tiny dots, called pixels that are arranged in a rectangular form. The sharpness of the image depends upon the number of pixels.

Printers :-

Printer is an output device, which is used to print information on paper.

Speakers:-

A hardware device connected to a computer's sound card that outputs sound generated by the computer.

Headphone:-

Headphones are a pair of small listening devices that are designed to be worn on or around the head over a user's ears. They are electroacoustic transducers, which convert an electrical signal to a corresponding sound in the user's ear.