Hardware Components
Learning Outcomes
- Recognize different components of a computer.
- Explain the usage of different components.
- Differentiate between external and internal hardware.
- List examples of external and internal hardware.
Earlier, computers were used mostly by scientists and engineers for complex calculations and they were very costly too. But, nowadays, computers are within the reach of every working person. They have virtually become a need in every sphere of life.
A computer comprises two major components: hardware and software. The physical components of a computer that you can touch and feel are known as hardware. Hardware can be further categorized into internal and external hardware. A software is a set of programs that instructs a computer about the work to be done. Software can be classified into two main categories: system software (operating system, utility software, etc.) and application software (Word, PowerPoint, Paint, etc.).
Hardware and software are interdependent on each other. Without these two components, a computer cannot work. Let us learn about the different hardware components of a computer system, in detail.
Internal Hardware
The hardware components that are installed inside the CPU cabinet are called internal hardware. For example, CPU, RAM, ROM, disk drives, Motherboard, Network card, Sound card, Video card, etc.
Motherboard
A motherboard is the main circuit board of a computer that holds the
most essential components of the computer system. The base of a
motherboard consists of a rigid plastic sheet, known as a Printed
Circuit Board (PCB). It serves as a single platform to connect all the
parts of a computer system together and allows them to communicate with
each other. A motherboard is mounted inside the CPU cabinet and connects
CPU, memory, hard drives, optical drives, video card, sound card, and
the other expansion cards directly or via cables.
A motherboard mainly contains:
- Processor chip (CPU)
- Basic Input/Output System (BIOS)
- Memory chips (RAM and ROM)
- External storage controllers for video display and sound
- Expansion slots for connecting additional circuit boards
Central Processing Unit (CPU)
The CPU is alternately referred to as a microprocessor. It processes all
the data and instructions that it receives from hardware and software
running on a computer and produces results in the form of output. The
CPU is small in size, fixed on the motherboard. It is usually in the
shape of a square or rectangle, which consists of millions of very small
components, including transistors, resistors, and diodes that work
together to perform a wide variety of functions. The speed of the CPU is
determined by the number of instructions it executes per second, which
is measured in gigahertz (GHz).
There are mainly three components of a CPU:
Memory Unit (MU):
It is the principal storage of the computer. It stores both data and instructions when entered.
Arithmetic and Logical Unit (ALU)
This unit performs the arithmetic and logical operations.
Control Unit (CU)
It controls the operation of every other component of a computer system. This unit also controls the transfer of data and instructions among the other units of computer.
RAM
RAM stands for Random Access Memory. It stores the information temporarily and can be constantly overwritten with the new data. The information stored in the memory is lost when you turn off the computer or the power goes off. That is why, it is known as volatile memory. It is directly accessed by the CPU, and known as the fastest memory of the computer system. The most common RAM size that you can find on computers and laptops is 2 GB, 4 GB, 8 GB, so on. RAM is of two types: Static RAM and Dynamic RAM.
ROM
ROM stands for Read Only Memory. It holds the start up instructions that prepare a computer for use. It also consists of programs that check the proper working of all the computer parts when you turn it on. The instructions stored in ROM cannot be changed, but can only be read. Unlike RAM, ROM a is nonvolatile memory. It retains the stored information even when the power has been switched off. There are different types of ROM: PROM, EPROM, EEPROM, etc.
Disk Drive
A disk drive is a hardware component in a computer that enables the users to read, write, delete, and modify data on a storage disk. It is either a built-in or external component of a disk that manages the input/output (I/O) operations of a disk. Disk drives are of several types, such as Hard Disk drive, CD drive, DVD drive, etc. The most commonly used disk drive is the Hard Disk drive.
Hard Disk
A hard disk is a magnetic storage device used to store and retrieve
data.
Nowadays, hard disk come in various capacities, 512 GB, 1 TB, 5 TB, and
so on. A hard disk is generally embedded within the disk itself or
housed in a separate box external to the computer. It is made up of a
collection of disks known as platters, stacked on top of each other.
Each platter consists of two read/write heads on both the sides for
reading the stored data. All the read/write heads are attached to a
single access arm so that they do not move independently. Each platter
has the same number of tracks to store data. A track location that cuts
across all platters is called a cylinder.
SMPS
SMPS stands for Switching-Mode Power Supply. It is essential for safe running of power consuming electrical and electronic components of the CPU. SMPS uses a switching regulator to control and stabilise the output voltage by switching the load current on or off. It transfers electric power from a source (AC mains) to low voltage Direct Current (DC). It always supplies a well-regulated power to the motherboard and the other parts of a computer and saves power. It has a built-in fan to release the excessive heat during the time computer is in use.
Modem
Modem stands for modulator-demodulator. It is a device that allows a computer to send or receive information through telephone lines by converting digital data into analog signals.
Modulator converts digital information of a computer to analog mode at the transmitting end and demodulator further converts back the analog signals to digital at the receiving end. Modems can be classified as: Internal Modem and External Modem.
Internal Modem
An internal modem comes pre-installed in the computer. PC card modems are specifically designed for portable computers. They are roughly the size of a credit card. The speed of a modem is measured in bps, i.e., bits per second.
External Modem
It is a modem that is installed outside the CPU. It is a box-like structure that is normally connected to USB port of a computer. This type of modem has indicator lights that display the speed of a modem, measured in bps, i.e., bits per second. If the telephone line quality is not good, it will not be able to work with its maximum speed.
Let's Know More
mechanical hard disks with flash-based A Solid-State drive (SSD) is a new generation of storage device used in computers or laptops. SSDs replace traditional memory, which is much faster. It speeds up computers significantly due to their short read access times and high performance.
Let's Know More
A sound card is a hardware component that is fixed either in an expansion slot or built into the motherboard. It handles the input and output of the sound signals.
A video card is also known as a graphics card. It is used to enhance the quality of the displayed images. Graphics cards come in four basic types: Integrated, PCI, AGP, and PCI-E cards.
Note
PC Card Modem is specifically designed for laptops and handheld computers. It is similar to the size of a credit card and fits into the PC Card slot on notebook and handheld computers.
Heat Sink
A heat sink is an electronic device, which is designed to disperse the heat generated by the CPU. It is made up of metal, such as a copper or aluminum alloy, and normally uses a fan to keep the processor cool.
Heat sink is commonly used in all CPUs. It is also used in refrigeration
and air
conditioning systems, Graphic Processing Systems (GPUs), and so on.
Ports
A computer port is a slot on the motherboard that acts as a point of connection between a computer and an external device. Cables of external devices, like keyboard, mouse, printer, monitor etc., are plugged into these ports to attach them to a computer.
There are several types of ports that are used to connect the various external devices to the computer.
Most of the ports are visible at the backside of the CPU cabinet while a few are placed in front. The placement of these ports may vary from computer to computer. Some of these ports are colour-coded to identify a specific device to be plugged in them.
Serial Port
It transfers the information in or out sequentially one bit at a time. It requires only one data line for data transmission. It is used to connect various peripherals, such as external modems, mouse, printers, PDAs, digital cameras, which are of the old model.
Parallel Port
It transfers several bits of data together at one time. It is used to connect scanners, printers, CD writer, external hard disk drive, etc.
USB
USB stands for Universal Serial Bus. Nowadays, keyboard, mouse, printers, scanners, flash drives, digital and web cameras, etc., come with USB cable connectors that are connected with the USB ports.
PS/2 Port
PS/2 connector was developed by IBM in 1987. PS/2 port is now considered
a legacy port as it has been replaced by the USB port. It was used for
attaching keyboard and mouse to a computer.
FireWire
It is also known as IEEE 1394, and developed by Apple Inc. It can
transfer a large amount of data with speed upto 800 Mbps and connect
upto 63 different devices.
You can use FireWire port to connect external devices, such as a hard
drive or digital video camera, without restarting your computer.
VGA
VGA stands for Video Graphics Array. This port is similar to a serial port connector. The only difference is that the serial port has pins, whereas VGA connector has holes. With the increase in the use of digital video, VGA ports are gradually being replaced by HDMI and display ports. It is used to connect monitors or projectors to a computer.
HDMI
HDMI stands for High Definition Multimedia Interface. It is a digital connector that can carry high definition video and audio. It can also send audio to different formats. It is used to connect high definition and ultra high definition devices, like computer monitors, HD TVs, gaming consoles, high definition cameras, etc., to a computer.
Ethernet Port
An ethernet RJ 45 connector looks like a telephone line RJ 11 connector.
It is used to connect your computer with a wired network.
.
Audio
Line-in: It enables a user to connect an external audio device with the
computer
Line-out: It allows external speakers, headphones, or other output
devices to be connected to the computer.
Mic port: It helps in plugging microphone into the computer.
External Hardware
The components that are attached to the computer externally, are called external hardware components. These are also known as Peripherals. These peripherals can be divided into three categories: Input devices, Output devices, and Storage devices.
Input Devices
Input devices are used to enter data and information into a computer. These devices convert the incoming data and instructions into a pattern of binary codes (understood by a computer) and then supply the converted data to the processor for processing.
Keyboard
Keyboard is one of the most important input devices used to input data and instructions into a computer. The commonly used keyboard has 104 keys, which can be divided into many groups based on their functions, such as Alphanumeric keys, Combination keys, Function keys, Navigation keys, and so on.
Mouse
Mouse is the most commonly used input and pointing device that lets you
select and move items on the screen. The left mouse button is used more
frequently than the right button. A single-click selects an item while
double-clicking opens the application. The right-click often displays a
list of commands on the screen.
You can also use a mouse to drag and drop an item on the screen, draw
free-hand lines, circles, boxes, so on. Let us know about two different
types of mouse.
Mechanical Mouse
This type of mouse has a metal or rubber ball on its lower side that can roll in all the directions. The screen pointer moves according to the movement of the ball, which is detected by the mechanical sensors within the mouse.
Optical Mouse
Optical mouse does not have any mechanical moving parts. It uses a light source, typically a Light-Emitting Diode (LED) and a light detector to detect the movement of the mouse. An optical mouse is more efficient than the mechanical mouse.
Scanner
It is an input device that scans text, images, and objects optically.
The scanned data is then converted into a digital image and displayed on
the computer screen.
Following are the different types of scanners:
Drum Scanner
This is a high-end and expensive scanner used by professionals. It uses Photomultiplier Tube (PMT) technology to scan images. In a drum scanner, the image or document to be scanned is mounted on a glass cylinder. At the centre of the cylinder, a sensor that separates the bounced light from the paper into three beams, optically Red, Green, and Blue, accurately rendering the image. The drum scanners are used mainly in the publishing industry to print high quality images in books and magazines.
Flatbed Scanner
This is a popular optical scanner. It has a flip-up cover protecting the glass window. In a flatbed scanner, the object to be scanned is placed face down on the glass window, which is then illuminated with a bright light. It uses the Charged Coupled Device (CCD) technology to read the entire area optically. Depending on its size, a flatbed scanner can fit standard or legal-sized documents and its flexible cover allows you to scan books, newspapers, articles, photographs, etc. The flatbed scanners are used in homes, schools, and medium-sized offices.
Sheetfed Scanner
It is also known as an automatic document scanner. It closely resembles a compact laser or inkjet printer and has a similar paper handling mechanism. It scans loose papers quickly and easily and helps to boost productivity at the workplace. It is a fast, reliable, versatile, and business-oriented scanner, mainly used in large organisations.
Handheld Scanner
This is a small manual device, which is dragged over the surface of the image to be scanned. These scanners are operated by hand. It is difficult to operate these scanners as they need a steady hand to scan objects in order to avoid distorted images. Bar code scanner is one of the most utilised handheld scanner used in shopping malls.
Microphone
It is an input device, used to record and store voice or any other sound into a computer, generally as a .wav file. It is also used for recording a narration in a PowerPoint presentation. It is used as a separate component for desktops but can be seen as an integrated component in some laptops. You can notice a special port in these computers where a microphone can be connected. A microphone is commonly used in video conferencing, speech recognition programs, radio broadcasting, recording, and sound amplifying systems.
Light Pen
It is a light-sensitive pointing device, commonly used to select or modify data on the screen. It allows the user to point on displayed objects or draw on the screen. Its operation is similar to a touch screen but has a greater positional accuracy. It is easy to use and helpful for programs, like Computer Aided Design (CAD).
Digital Camera
A digital camera is quite similar to a traditional camera that is used to capture both videos and photographs. These videos and images can be transferred to a computer through a data cable or by using a card reader for storing, editing, and printing, etc. Nowadays, mobile phones also have inbuilt digital cameras.
Web Camera
A web camera is a device connected to a computer for capturing still images and live videos. It is primarily used for video conferencing and live chatting with your friends and relatives using the internet.
Output Devicees
Output devices are used to display or print the processed data in a user
readable form. A computer can have several output devices attached to
it. Some of the common output devices are monitor, projector, printer,
and plotter. Storage devices store information for the future reference
of the user. The commonly used storage
devices are hard disk, pen drive, CD, and DVD. Let us know about these
hardware components of a computer, in detail.
Monitor
Monitor is the most common output device. It is also called Visual Display Unit (VDU). Just like a television, a monitor also displays the output on the screen. The picture on a monitor is made up of thousands of small coloured dots called pixels. The output displayed on the monitor is called soft copy. Some commonly used types of monitors are:
- Cathode Ray Tube (CRT) Monitors
- Liquid Crystal Display (LCD)
- Thin Film Transistor (TFT) monitors
- Light Emitting Diode (LED) monitors
Printer
A printer is a peripheral device that prints the information on a paper. A printed paper is called a hard copy. Modern printers are connected to a computer using a USB port or Wi-Fi connection. Printers vary in size, speed, b and cost. Printers can be categorised into the following:
Impact Printers
Impact printers allow physical contact between the printer head and paper, i.e., these printers print by the impact of printer head on the paper. They are also called character printers. Example: Daisy Wheel Printers, Dot-Matrix Printers, etc.
Non-Impact Printers
Non-Impact printers do not allow physical contact between the printing head and paper, i.e., they do not strike against the inked ribbon or the paper that is being printed. Only the ink used for printing, touches the paper. Non-impact printers have better print quality. Example: Thermal Printers, Ink Jet Printers, Laser Printers, etc.
Projector
A projector is an output device that takes the images generated by a computer and displays them onto a big screen, wall, or any other flat surface. A projector is commonly used in a school classroom for teaching, to project the presentation about some newly launched product or strategy, theaters for projecting films, and so on.
Plotter
A plotter is another example of the output device. It prints your work on paper, which is very large in size. It prints the output by moving coloured pens across the surface of a piece of paper. It is generally used for flex printing, such as banners, posters, maps, and so on. It can draw complex line art, including text, but does so very slowly because of the mechanical movement of the pens.
CD
CD stands for Compact Disc. It is an optical storage device. A CD is a thin, shiny, circular disc that can store up to 700 MB of data and measures 4.7 inches in diameter. A CD can hold text, graphics, sound, images, and videos. It can be used for data backup and storing software. To access data from a CD, you need to place it in the CD drive, which is located in the front panel of the CPU cabinet. There are two types of CD-ROMs:
- Compact Disc Recordable (CD-R)
- Compact Disc Re-Writable (CD-RW)
DVD
DVD stands for Digital Versatile Disc also known as Digital Video Disc. It is an optical storage device, used for data storage and recording movies with high video and sound quality. Though, a DVD is similar to a CD in shape and size, but a DVD can store data six times more than a CD. Its storage capacity varies from 4.7 GB to 17 GB. Like a CD, a DVD is also available in many versions, such as:
- DVD-R
- DVD-RW
- DVD+R
- DVD+RW
Blu-Ray Disc
Blu-ray disc is a new optical disc format that is rapidly replacing a DVD. The name Blu-ray has been derived from the blue-violet laser, which is used to read and write data. This disc has the same dimension as a DVD and CD but can hold upto 25 GB of data on a single layer and 50 GB of data on a dual layer disc. It is mainly used for storing high quality audio, video, and games.
Pen Drive
It is a small and portable flash memory data storage device, mainly used to transfer audio, video, and data files from the hard disk of one computer to another. It is a plug and play device and can be connected with the Universal Serial Bus (USB) port. It consists of a small Printed Circuit Board (PCB), which has the circuit elements and a USB connector that is electrically insulated and protected inside a plastic, metal, or rubberised case.
Pen drive is also called Flash drive or Thumb drive and available with the storage capacity of up to 1 TB of data.
Recap
- A computer comprises two major components: hardware and software.
- The physical components of a computer that you can touch and feel are known as hardware.
- Software is a set of programs that instructs a computer about the work to be done.
- The hardware components that are attached to a computer externally are called as external hardware components. They are also known as peripherals.
- The hardware components that are installed within a CPU cabinet are called the internal hardware.
- A motherboard is the main circuit board of a computer that holds the most essential components of the computer system.
- CPU is the main unit of a computer. It is alternately referred to as a microprocessor.
- A computer port is a slot on the motherboard that acts as a point of connection between a computer and an external device.
- A modem allows a computer to send or receive information through telephone lines by converting digital data into analog signals and vice versa.
- USB devices, such as keyboard, mouse, printers, scanners, flash drives, digital and web cameras, etc., are connected with the USB ports.