Computer Hardware Components - Internal hardware and External hardware

1. Computer – Hardware Components

2. A computer is a machine that can perform a variety of operations in accordance with a set of
instructions called program. It processes the input data given by the programmer/user and
provides the desired information as output.

3. Computers have made life easier for everyone in the world. They are being used
everywhere in nearly all the fields such as banking, railways, airways, hotels, schools,
colleges, shops, industries, defence and designing.
Computers are mainly used in :-

4. Computer works with an interaction of hardware and software. Both hardware and software
are dependent on each other. Devices like CPU, memory unit and hard disk are useless unless
they are provided with instructions and data for storage and processing.

5. Computer System
Hardware Software

6. Hardware refers to any physical component of a computer. Monitor, keyboard and hard disk
are physical components and thus, are hardware. The most important piece of hardware is a
CPU. It is called the ‘brain’ of the computer.
Hardware

7. Software refers to the programs, which are required to operate the computer. Windows,
Windows media player, Google Chrome and Microsoft Office are all software.
Software

8. Hardware
Internal Hardware External Hardware
Hardware is classified into two types:

9. Internal Hardware -The hardware parts that are installed within the CPU cabinet are called internal
hardware. Motherboard, CPU, RAM, ROM and sound card are some examples of internal hardware.
Internal Hardware

10. A motherboard is a sheet of plastic that
holds all the circuitry to connect various
components of a computer system. It is
one of the most essential parts of a
computer system. It holds together many
crucial components of a computer,
including the CPU, memory and
connectors for input and output devices.
In addition to circuits, motherboard
contains a number of sockets and slots to
connect other components. All the
activities related to the connected devices
start and end in the motherboard.

11. A motherboard mainly consists of the following.
• Processor chip • BIOS • Memory chips •
External storage controllers for video display
and audio • Expansion slots for connecting
additional circuit boards

12. Sound Card Sound cards are also known as audio
adapters. A sound card is an expansion component
used in computers to receive and send audio.
Sound cards are configured and utilised with the
help of a software and a device driver.
The input device attached to receive audio data is
usually a microphone, whereas the devices used
for audio output are generally speakers and
headphones.

13. The sound card converts incoming digital
audio data into analog audio so that the
speakers can play it. In the reverse case, the
sound card can convert analog audio data
from the microphone into digital data that
can be stored on the computer.

14. Video Card A video card is also
known as a graphics card. It is an
expansion card connected to a
motherboard, that is used to
generate the video output on a
screen such as monitor and
television. It enhances the
quality of the displayed images,
and contains its own processing
and memory unit.

15. • CPU The Central Processing Unit (CPU)
is the primary element of a computer. It
carries out each instruction of a
program in a sequence to perform the
basic operations of the system.
• In other words, it performs arithmetic
and logical calculations of the data.
• The CPU is capable of storing enormous
amount of data and processing them at
a high speed and producing useful
results.

16. The three components of a CPU are listed below.
1. Arithmetic Logic Unit (ALU): It performs
arithmetic and logical operations.
2. Control Unit (CU): It extracts instructions from
the memory, decodes and executes them.
3. Memory Unit (MU): A computer has a large
storage capacity. The storage capacity of a
computer is called its memory. Memory enables a
computer to store data and instructions.

17. • RAM Random Access Memory (RAM) is used
to store data and instructions during the
execution of programs.
• RAM is temporary and is erased when a
computer is switched off .
• Hence, RAM is a volatile memory. It is a read/
write type of memory, and thus can only be
read and written by the user/programmer.
• As it is possible to randomly use any location
of this memory, therefore, this memory is
known as random access memory.

18. Two types of RAM are used in PCs: dynamic RAM
and static RAM.
• Dynamic RAM (DRAM): The information stored in
dynamic RAM has to be refreshed after every few
milliseconds, otherwise it is erased. DRAM is mostly
used for system memory because it is cheaper and
has a higher storage capacity than static RAM.
• Static RAM (SRAM): The information stored in static
RAM need not be refreshed, but it remains stable as
long as the power supply is provided. SRAM is costlier
but has a higher speed than DRAM.

19. ROM Read Only Memory (ROM) is an essential component of the memory unit. A computer, being a machine, itself has no
intelligence or memory and it requires instructions which are given by man. Whenever a computer is switched on, it
searches for the required instructions. The memory consisting of these essential instructions is known as read only
memory. This memory is permanent and is not erased when the system is switched off . So, ROM is a non-volatile memory.
As is clear from its name, it is read type of memory, i.e., it can be read only and not be written by user/programmer.

20. Types of ROM There are various types of ROM available for microcomputers like PROM, EPROM and EEPROM.
• PROM: It stands for Programmable Read Only Memory. In this type of ROM, the information is stored by programmers after
its manufacturing. It cannot be altered or erased later on.

21. • EPROM: It stands for Erasable Programmable Read Only Memory. It is similar to PROM, but its information can be
erased later on by ultraviolet light and it can be reprogrammed.

22. • EEPROM: It stands for Electrically Erasable Programmable Read Only Memory. It is similar to EPROM but its
information can be erased by using a high voltage current.

23. Disk Drive A disk drive enables the users to read, write, delete and modify data on a storage disk. It manages the
input/output operations of the disk. It can be either external or inbuilt component of a disk. The most common type of disk
drive is a hard drive, but several other types of disk drives exist as well. Some examples include removable storage devices,
floppy drives and optical drive

24. Switched Mode Power Supply (SMPS) SMPS is essential for safe running of power-consuming appliances. Switching power
supplies have high efficiency and are widely used in a variety of electronic equipments, including computers and other
sensitive equipments requiring stable and efficient power supply. It also contains inbuilt fans to release excessive heat
generated during the computer use.

25. MODEM The term MODEM is formed by combining the words MO-dulation and DEM-odulation. MODEM is a data
communication equipment that translates the digital signals used by a computer into analog signals of the kind that travel by
conventional telephone lines. The process of translating digital signals into analog signals is called modulation.

26. A MODEM also converts the analog signals into digital signals at the receiving end of a computing device. The process
which translates analog signals into digital signals is called demodulation. The basic function of a MODEM is to enable
communication between various computers on a network (mainly Internet).

27. There are mainly two types of MODEM: internal and external. An internal MODEM is a card that is installed
into a slot within the CPU case of a computer. Internal modem is powered by the power supply of a computer.
An external MODEM is a box-shaped device that is connected to the serial port of a computer. It is so called as
it is placed outside the computer. The external modem is powered by an external power adapter, connected to
an electrical outlet.

28. Heat Sink A heat sink is an electronic device designed to disperse the heat generated by the CPU and cools
it for improving performance and reliability. It also avoids the premature failure of the components.

29. Port A computer port is a connection between a computer and
an external or internal device. Internal ports may connect
devices such as hard drives and CD ROM or DVD drives. External
ports may connect modems, printers, mouse and other devices.
Definition
•Ports are connecting sockets, used to connect peripheral devices
on the system unit.
Description
•Hardware ports are usually male or female type.
•Software ports are virtual or logical connection needed to
exchange information between the programs.
•Several hardware ports are available at backside of the cabinet
like keyboard, mouse, monitor, printer, modem etc.

30. Characteristics of Ports A port has the following
characteristics. • External devices are connected to a
computer using cables and ports. • Ports are slots on
the motherboard into which the cable of an external
device is plugged in. Computer ports have numerous
functions and connectors of varying designs.

31. 1. Serial Port
Serial port involves the transmission of data one
bit at a time over a single communication line.
Use: It is used for external MODEM and older
computer mouse that do not require high speed
transmission.

32. 2. Parallel Port
•Parallel port transfers the data in or out in parallel
using more than one communication line or wire.
• To connect external devices that sends lot of data
over a short distance.
•Sends 8 bit data simultaneously over 8 pins.
Use: It is used for scanners and printers that
require high speed transmission.

33. 3. PS/2 Port PS/2 port is also called mouse port. PS/2 port is now considered a legacy port as the
USB port has replaced it and very few modern motherboards include it as a legacy port.
Use: It is used for old computer keyboard and mouse. Most of the old computers provide two PS/2
port, one for the mouse and one for keyboard.

34. 4. Universal Serial Bus (USB) USB
can connect all kinds of external
USB devices such as external hard
disk, printer, scanner, mouse and
keyboard.
Use: It is used to transfer data and
also act as a power supply for
devices connected to it.

35. 5. Video Graphics Array (VGA) VGA
port is the main interface between
computers and older CRT monitors.
It is similar to the serial port
connector that has pins. However,
VGA port has holes. Even modern
LCD and LED monitors support VGA
ports but the picture quality is
reduced.

36. 5 With the increase in the use of digital video, VGA ports are gradually being replaced by HDMI and
display ports. Some laptops are equipped with on-board VGA ports in order to connect to external
monitors or projectors. Use: It connects monitor to a computer’s video card.

37. 6. Firewire Port Firewire port is developed by Apple. It transfers large amount of data at a very fast speed.
Use: It connects camcorders and video equipments to the computer.

38. 7. Ethernet port resides on an ethernet card. Data travels at 10 megabits to 1000 megabits per second depending
upon the network bandwidth.
Use: It connects the network cable to a computer. It connects to a network and high speed Internet.
Ethernet ports:
Also called as RJ45 ports.
Most computer and laptop includes one built-in Ethernet port for connecting to a wired Local Area Network (LAN).
Data rate speed varies from 10 MBPS - 1000 MBPS depending upon the type of port used like 10BaseT - 10 MBPS,
100BaseT - 100 MBPS and Giga Ethernet - 1000 MBPS.

39. External hardware are also called peripherals. The devices attached to the computer externally are called
external hardware. Input devices, output devices and storage devices are examples of external hardware.

40. Input devices feed information, data and
instructions to a computer. The computer
accepts and processes them before giving
the output.

41. Keyboard, the most common and
essential input device of a
computer is similar to a
typewriter.
However, there are more keys
present on a computer keyboard
than on a typewriter.
The most commonly used
keyboard (QWERTY keyboard) has
105 keys.

42. A keyboard consists of five types of keys.
Typing keys:
They consist of :-
• Alphabet keys (A–Z)
• Number keys (0–9)
• Punctuation keys (?, >, <, etc.)
• Special symbols keys (&, #, etc.).
These keys also include Caps Lock, Shift,
Backspace, Enter, Spacebar and Tab keys.

43. • Control keys: They can either be used
alone or in combination with other keys
to perform an action.
Ctrl, Alt and Esc are some control keys.
• Function keys: There are 12 keys that
are present at the top row of the
keyboard and are used to perform
specific tasks. F1, F2, F3, F4, F5, F6, F7,
F8, F9, F10, F11 and F12 are the function
keys.

44. • Navigation keys: They are used to
move through the document. Home,
Insert, End and Arrow keys are the
navigation keys.
• Numeric keypad: It is placed at the
right side of the keyboard.
It consists of number key 0–9, arithmetic
operators and the decimal point.