Learning Objectives At the end of this class, you will be able to:

Define hardware Tell what are output devices Tell what is CPU Tell what is UPS Identify Laptops and Tablets

Hardware Figure below shows the various hardware components of a computer and the way they interact with each other.

CENTRALPROCESSING

UNITINPUT UNIT OUTPUT UNIT

MEMORY UNIT

OUTPUT DEVICES

INPUT DEVICES

OTHER DEVICES

Input Devices These are use to enter data in a computer.Keyboard , mouse and scanner are someexamples of input devices.

Input Devices

Keyboard

Information is typed on the keyboard. It converts the keystrokes into electrical signals that a computer can understand.

Input DevicesKeyboar

d

Input Devices

Mouse Movements of a mouse and displayed on the screen. Mouse offers clicking options to perform certain task.

Input DevicesMouse

Input DevicesJoystick

A joystick is a lever that moves in all directions and controls the movement of a pointer on the screen. A joystick pointer keeps scrolling till the joystick is brought back to the upright position. Most joysticks include two buttons called triggers. It is mostly used in computer games.

Input DevicesJoystick

Input Devices

Light pen A light pen is like a pen that has a light sensitive detector at its tip. You can select items by moving a light pen over a screen.

Input DevicesLight pen

Input DevicesBarcode reader

A barcode reader is required to read the information given in the form of a barcode. It uses a beam of light to read a barcode. A digital circuit present inside converts the signal into meaningful data.

Input Devices

Barcode reader

Input DevicesTrackball

It is similar to a mouse in which we move the ball with fingers or palm. It takes up less space than a mouse since it remains fixed. It has pointer options similar to a mouse.

Input Devices

Trackball

Input DevicesScanner

A scanner creates a picture file in a computer from a photograph or hard copy (paper document)

Input DevicesScanner

Input DevicesTouch screen

It is a type of screen that reads the user’s choice according to where it is touched. Touch screen is very convenient and consumes no extra space. But it can allow only limited type of operations. Touch screen terminals are used in public places, like railway stations, to provide information.

Input DevicesTouch screen

Input Devices

Touchpad It is type of pad with sensor detector. Touchpad can be operated by moving fingers on it. It also has buttons similar to a mouse.

Input DevicesTouchpad

Hardware Figure below shows the various hardware components of a computer and the way they interact with each other.

CENTRALPROCESSING

UNITINPUT UNIT OUTPUT UNIT

OUTPUT DEVICES

INPUT DEVICES

Output Devices The result obtained by the computer is the output. Output devices let you see the work that you are doing. They also allow you to hear sounds and they provide you with hard copies of your documents.

Output Devices

It displays characters and graphicson a television-like screen.

Monitor

CRT LCD

Output Devices A cathode-ray tube (CRT) monitor is a type of monitor that has a glass tube that is narrow at on end and opens to a flat screen at the other end. The shape of a monitor screen can be rectangular, circular or square shaped.

Monitor CRT

Output Devices A liquid-crystals display (LCD) monitor is thinner, lighter, and less spacious than a CRT. One advantage of using it is that it consumes less energy conserving some electricity.

Monitor LCD

Output Devices

Output Devices

Speakers are output devices that let you listen to sounds from your computer. They come in various sizes and colors and usually come in pair. Speakers function just like a stereo loudspeaker which you can adjust according to your desired volume.

Speakers

Output Devices

Output Devices Printer take text and pictures from a computer and print them on paper.

Printer

Dot matrix Printer

Inkjet Printer

Laser Printer

Output Devices

It uses an inked ribbon against which striking pins make dots on paper. Different combinations of dots form different characters.

Dot matrix Printer

Output DevicesHow a dot matrix printer

works?

Ink dot

Inked ribbon

Pins

Output Devices

The characters are printed by spraying ink on paper. It produces high quality text and graphics.

Inkjet Printer

Output DevicesHow an ink jet printer

works?Print head

Ink droplets

Print media

Finished printed image

Output Devices

It uses laser beams to produce printouts of high quality. Laser printers are very fast and can handle huge amount of printing. They are costlier than the other types of printers.

Laser Printer

Output DevicesHow a laser printer

works?Paper is fed into the

machine.The printer’s processor decodes output data from the computer.Instructions from the printer’s processor turns a laser beam rapidly on and off.The paper is fed through the fusing unit where the toner is permanently abound to the paper by heat and pressure.The paper is discharged out of the machine.

Output Devices

Output Devices

These output devices let only the user alone to listen to the sound of the computer. These are connected to a band designed to be placed over the listeners’ ears. Today’s headphones are designed light and bulky.

Headphones

Output Devices

Hardware Figure below shows the various hardware components of a computer and the way they interact with each other.

CENTRALPROCESSING

UNITINPUT UNIT OUTPUT UNIT

OUTPUT DEVICES

INPUT DEVICES

Central Processing Unit Central Processing Unit commonly known

as the CPU, is the brain of the computer. It is the CPU that performs all the functions of the computer.

The CPU is a part of the computer system that processes the input data.

It also reads and executes instruction that you have given.

The CPU controls the functions of all the components attached to it.

The computer memory is found in the CPU

Central Processing UnitA CPU is made of

Memory UnitThe memory unit stores the data andinstructions temporarily for processing.Control UnitThe control unit controls the working of allparts of the computer based on theinstructions received from the inputdevices.Arithmetic logic Unit (ALU)The ALU performs all the mathematicaloperations like addition, subtraction,multiplication and division as well as

logical operations like comparison (<,>,=).

MEMORY Computers have the capability to store huge amount of data. The storage is done in hardware component called the memory unit. In memory unit, computer uses bits to store data. A bit is a binary digit, which can be either 0 or 1. A group of 8 bits is known as a byte. Computer memory is expressed in terms of bytes.

MEMORY 1024 bytes or 210 bytes = 1 kilobyte or KB1024 KB or 220 bytes = 1 megabyte or MB1024 MB or 230 bytes = 1 gigabyte or GB1024 GB or 240 bytes = 1 terabyte or TB

Memory is classified into primary and secondary.

MEMORY Primary memory

It is used by the processor for storing data temporarily. Primary memory is also known as Random Access Memory (RAM). When a program is opened, it is loaded (copied) in RAM; once the program is closed, it is deleted from RAM. It is very fast and is also expensive. In most computer, the size of the primary memory is about 4 to 8 GB.

MEMORY RAM

RAM stands for Random Access Memory. It is only a temporary memory. It stores data and instructions while the computer is turned on. When the computer is off, all the data stored in it is lost. RAM can pick out, or access, any piece of data from any point. So it is important to save your files before turning your PC off so that you can have it whenever you turn your PC back on.

MEMORY ROM

ROM stands for Read Only Memory. Rom holds information that is built into it. Information stored on ROM cannot be modified or changed. You can only read the information from ROM.

MEMORY Secondary memory

It is mainly used for storing user’s data/information for longer period of time. It is slower than primary memory and cheaper as well. Examples are hard disk, CD/DVD, floppy disk and flash memory device (pen drive). Most computers have hard disks with a capacity of 700 to 800 GB.

MEMORY Compact Discs

A CD can store up to 700MB of data, which is equivalent to 80 minutes of audio, hundreds of quality images, and a number of small video files.

A DVD is a storage device. It is a storage device that has the same diameter as a CD but have the capacity to contain much more data. It is originally known as the digital video disc but because of its many potential uses, it was renamed digital versatile disc.

MEMORY Floppy Discs

A floppy disc is a storage device with a plastic casing. Inside it is a very thin piece of plastic coated with microscopic iron particles. The first 8 in floppy disc was developed by IBM in the late 1960s. It was invented by David Noble, an engineer of IBM. The first 3.5 in floppy discs was developed by Sony and was sold in 1981.

MEMORY USB Flash Drive

USB flash drives are another type of computer storage devices. They have a higher memory capacity and is faster than a DVD or a CD. Because of their small size, you can put them in your pocket and bring them anywhere. You can also wear them as necklaces, and as key chains for your belongings.

Hardware Figure below shows the various hardware components of a computer and the way they interact with each other.

CENTRALPROCESSING

UNITINPUT UNIT OUTPUT UNIT

MEMORY UNIT

OUTPUT DEVICES

INPUT DEVICES

OTHER DEVICES

Uninterrupted Power Supply

An Uninterrupted Power Supply (UPS) is a device that prevents sudden power fluctuations and failures. It provides continuous supply of power from a rechargeable battery contained in it. In case the mains power goes off, it gives a beep sound. Depending on its capacity, a UPS can provide power backup for 15 minutes to 1 hour.

Laptops and Tablets These have evolved as result of further development of computers. They are lighter and take up less space than a desktop. LaptopA laptop has the following components:- LCD monitor- Keyboard- Touchpad / Trackball

Tablet PC The tablet PC is a thin notebook shaped computer with touch screen. They are smaller and lighter than laptops and can be carried around.

ExercisesClassify the various of hardwaer in the

table.Input unit CPU Output unit Memory

unitOther

devices

ExercisesClassify the various of hardwaer in the

table.Input unit CPU Output unit Memory unit Other devices

KEYBOARD CONTROL UNIT

MONITOR ROM UNINTERRUPTED POWER SUPPLY(UPS)MOUSE SPEAKER RAM

JOYSTICK ARITHMETIC AND LOGIC UNIT

PRINTER COMPACT DISK

LIGHT PEN DOTMATRIX PRINTER

FLOPPY DISK LAPTOP

BARCODE READER

INKJE PRINTER FLASH MEMORY DEVICE

TABLET PC

TRACKBALL LASER PRINTERSCANNER

TOUCHSCREEN

TOUCHPAD

Hard wareExercises

Hard wareExercises