Input and Output Devices
Input Devices :
Input devices are necessary to convert our information or data into a form which can be understood by the computer. A good input device should provide timely, accurate and useful data to the main memory of the computer for processing.
Below are the Most Useful Input devices :
Keyboard devices are online devices that are used for entering data directly into a computer. Data is entered into the computer by- pressing a set of keys available with these devices. Keyboard devices are becoming more and more popular day-to-day. They are extensively being used today as both input and output devices. Improper use or positioning of a keyboard can lead to repetitive stress injuries.
Scanners are basically input devices that are capable or recognizing marks or characters. They are used for direct data entry into the computer system. They also eliminate some of the duplications of human effort required to get data into the computer.
The mouse is an input device that is used with our personal computer. It rolls on a small ball and has two or three buttons on the top. We use a mouse because the cursor moves very fast with mouse giving us more freedom to work in any direction. It is easier and faster to move through a mouse.
The Trackball is another pointing device that resembles a ball nestled in a square cradle and serves as an alternative to a mouse. In general, a trackball is as if a mouse is turned upside down. It has a ball which can be rotated by fingers in any direction, the cursor moves accordingly. The size of the ball in the trackball varies from as large as a cue ball, to as small as a marble. Since it is a static device, instead of rolling the mouse on top of the table the ball on the top is moved by using fingers, thumbs, and palms.
5. Light Pen:
It is a pen-shaped device used to select objects on a display screen. It is quite like the mouse but uses a light pen to move the pointer and select any object on the screen by pointing to the object. Users of Computer Aided Design (CAD) applications commonly use the light pens to directly draw on the screen.
Output Devices :
An output device is a device which is used to send data from a computer to another device or user. The most computer data output that is meant for humans is in the form of audio or video. So, most of the output devices used by humans are in these categories.
For Example, Printers, and Plotters.
It is an important output device which can be used to get a printed copy of the processed text or result on paper. There are different types of printers that are designed for different types of application. Depending on their speed and approach to printing, printers are classified as :
- Impact Printers: Impact printers use the familiar typewriter approach of hammering a typeface against the paper and inked ribbon.
For example, Dot Matrix Printer.
- Non-Impact Printers: Non-impact printers do not hit or impact a ribbon to print. They use electro-static chemicals and inkjet technologies.
For example, Laser Printers and Inkjet Printers.
They take the information on our screen and transfer it to paper or a hard copy.
The three main types of printers are dot matrix, inkjet, laser printer.
- Dot Matrix Printer: Dot matrix printers use small electromagnetically activated pins in the print head, and an inked ribbon, to produce images by the impact.
- Inkjet Printer: Inkjet printers work like DMP but fire a stream of ink from a cartridge directly onto the paper.
- Laser Printer: Laser printers use the same technology as a photocopier using heat to transfer toner. Laser printer produces goods quality images by the same technology that photocopiers use.
The plotter is an important output device, used to print high-quality graphics and drawings. Although the graphics can be printed on printers, the resolution of such printing is limited on printers. Plotters are generally used for printing/drawing graphical images such as charts, drawings, maps etc. of engineering and scientific applications.
Types of Plotter :
Some important types of plotters are as follows :
- Flat Bed Plotters: These plotters print the graphical images by moving the pen on the stationary flat surface material. They produce very accurate drawings.
- Drum Plotters: These plotters print graphical images by moving both the pen and the drum having paper. They do not produce as accurate drawings as printed by flatbed plotters.
- Inkjet Plotters: These plotters use inkjets in place of pens. They are faster than flatbed plotters and can print multi-colored large drawings.