HARDWARE

INPUT AND OUTPUT Input Unit •This unit contains devices with the help of which we enter data into computer. • This unit makes link between user and computer. •The input devices translate the information into the form understandable by computer. Output Unit •Output unit consists of devices with the help of which we get the information from computer. •This unit is a link between computer and users. •Output devices translate the computer's output into the form understandable by users. CPU(Central Processing Unit)

•CPU is considered as the brain of the computer. •CPU performs all types of data processing operations. • It stores data, intermediate results and instructions(program).  It controls the operation of all parts of computer.

CPU itself has following three components •ALU(Arithmetic Logic Unit) •Memory Unit Control Unit

INPUT DEVICE

Following are few of the important input devices which are used in a computer:

•Keyboard

•Mouse

•Joy Stick

•Light pen

•Track Ball

•Scanner

•Graphic Tablet

•Microphone

•Magnetic Ink Card Reader(MICR)

•Optical Character Reader(OCR)

•Bar Code Reader

Optical Mark Reader(OMR)

KEYBOARD

•Keyboard is the most common and very popular input device which helps in inputting data to the computer.

•The layout of the keyboard is like that of traditional typewriter, although there are some additional keys provided for performing additional functions.

Keyboards are of two sizes 84 keys or 101/102 keys, but now keyboards with 104 keys or 108 keys are also available for Windows and Internet

SCANER

 

•Scanner is an input device which works more like a photocopy machine.

•It is used when some information is available on a paper and it is to be transferred to the hard disc of the computer for further manipulation.

•Scanner captures images from the source which are then converted into the digital form that can be stored on the disc.

•These images can be edited before they are printed.

SCANNER

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.

OUTPUT DEVICE Following are few of the important output devices which are used in a computer. •Monitors •Graphic Plotter •Printer Monitors •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. MONITOR

LCD

PRINTER Printer is an output device, which is used to print information on paper. There are two types of printers: •Impact Printers •Non-Impact Printers Impact Printers •The impact printers print the characters by striking them on the ribbon which is then pressed on the paper. Characteristics of Impact Printers are the following: •Very low consumable costs •Very noisy •Useful for bulk printing due to low cost There is physical contact with the paper to produce an image

INKJET PRINTER