1 Input devices
Input devices are most important components for computer, that enable users to interact with a
computer. Without input devices, we cannot be able to feed instructions to a computer.
This input device with typical typewriter style layout has 104 buttons. The enhancements to
the older model include addition of extra keys making it easy for multimedia and internet
operations. Various fancy models are available in the market which claim to be ergonomic but
it’s entirely on acceptability of users. Cordless keyboard like the mouse is preferred and less
of wires ease the working area clutter of wires.
It controls the cursor movement on the screen. Mouse with the ball at their base are most
common, but the optical mouse is catching the market very rapidly and replacing the traditional
old mousse. Optical mouse has greater accuracy and smoothness of cursor movement. There
are also other enhancements such as scroll roller between left and right buttons of mice, which
helps in scrolling.
? Easy use
? Not expensive
Scanner is a most popular input devise. Its works more like a photocopy machine. It’s scans
documents such as photographs and page of text. Scanners are converted documents to digital
3.2 Output devise
We use many output devices. Output devise is most important things of users 1. Its send data
from a computer to another device or users.
A printer is an output devise. The printer accepts text and graphics output from a computer and
transfers the information to paper. There are 3 types of printers.
I. Dot-matrix printers
II. Ink-jet printers
III. Laser printers
The monitor or the displays systems are available in different types like CRT (cathode ray tube)
s, TFTs LCDs etc. the main competitive aspect among the members of this category is the
clarity of picture and strain on the eyes of users. CRT or the most monitors are also available
with high quality of picture and low radiations, but LCDs are still leading the race, these days
mostly 17″ CRT monitors are preferred due to their “lower price better performance” formula.
LCDs are still the costly affair for the normal home user.
3.2.3 Multimedia projector
Multimedia projector is an output devise. its high resolution, full color projector capable of
projecting text, video, image and audio content. We can use that one in classrooms, offices and
gatherings at which multimedia presentation are made
3.3 Input and output device
This is special hardware for computer and user. It’s can output the information and same time
we can give to input some information or data
3.3.1 Touch screen
Touch screen is an input and output device. Its specially designed for input and output. Touch
screens are accepts input when our finger or an object comes in contact with the screen 2.
These are output work is done by the LCD or LED displays, which displays some images and
text on screen. These are useful for ATM, railway station and airport.
Modem is input and output devise. This device connects your computer to outside word. It
enables the activity called internet. Various types include hard, soft, internal and external
modems. Though these days, only soft modems are used. Internal soft modems get mounted
inside the computer while external modem stays outside. Normally 56.6 Kbps modems are
Speakers or headphones output devices that can play sound. We can control the output volume
up or down. We usually use webcam has a microphone. We can give to voice or some data for
microphone. So it’s can be performing an input devise.
3.4 Storage device
Storage device is a hardware. It’s can be holding information either temporarily or
permanently 3. There are 02 types of storage device. First one is primary storage
device, such as RAM, second one is secondary storage devise like a hard drive.
3.4.1 Hard disk
The term hard is used to distinguish it from a soft, or floppy, disk. Hard disk. Hard disks hold
more data and are faster than floppy disks. A hard disk, for example, can store anywhere from
10 to more than 100 gigabytes, whereas most floppies have a maximum storage capacity of 1.4
megabytes. In general, hard disks are less portable than floppies, although it is possible to buy
removable hard disks. The one with good rotation speed such as 7200 RPM or higher are the
performance oriented compared to 5400 RPM drives, which are comparatively slow.
3.4.2 DVD (Digital Versatile Disc)
DVD is a storage devise. These are have 4.7 gigabytes capacity. We can save audio, video and
3.4.3 RAM (Random Access Memory)
This is a storage device. Specially called by primary storage device. Random Access memory
is considered to be the most important element after the CPU. The speed of a PC is directly
proportional to the size of RAM.
3.5 Processing device
When we give to some data for the computer in input device, the data go to intermediate stage
and it can be sent to an output devise 4.
3.5.1 CPU (central processing unit)
The processor can be termed as heart of a computer. Its speed is measured in MHz (MegaHertz)
or GHz (GigaHerts). Based on its clock speed.
3.5.2 Mother board
This is the main circuit board of a microcomputer. The motherboard contains the connectors
for attaching additional boards. Typically, the motherboard contains the CPU, BIOS, memory,
mass storage interfaces, serial and parallel ports, expansion slots, and all the controllers
required to control standard peripheral devices, such as the displays screen, keyboard, and disk
drive. Collectively, all these chips that reside on the motherboard are known as the
motherboard’s chipset. On most PCs, it is possible to add memory chips directly to the
motherboard. You may also be able to upgrade to a faster PC by replacing the CPU chip. To
add additional core features, you may need to replace the motherboard entirely.
3.5.3 Network card
Most commonly called as LAN card they facilitate our computers’ connectivity with another
computer. Mounted inside the computer they have special type of connector points on its outer
surface. 10/100 Ethernet LAN card for the broadband internet connection and the speed is