Peripheral

A peripheral is a “device that is used to put information into or get information out of the computer.”

There are three different types of peripherals:

• Input, used to interact with, or send data to the computer (mouse, keyboards, etc.)
• Output, which provides output to the user from the computer (monitors, printers, etc.)
• Storage, which stores data processed by the computer (hard drives, flash drives, etc.)

Overview

A peripheral device is generally defined as any auxiliary device such as a computer mouse or keyboard that connects to and works with the computer in some way. Other examples of peripherals are expansion cards, graphics cards, image scanners, tape drives, microphones, loudspeakers, webcams, and digital cameras. RAM—random access memory—straddles the line between peripheral and primary component; it is technically a storage peripheral, but is required for every major function of a modern computer and removing the RAM will effectively disable any modern machine. Many new devices such as digital watches, smartphones and tablet computers have interfaces which allow them to be used as a peripheral by a full computer, though they are not host-dependent as other peripheral devices are. According to the most technical definition, the only pieces of a computer not considered to be peripherals are the central processing unit, power supply, motherboard, and computer case.

Common Peripherals

Input

• Keyboard
• Computer mouse
• Graphic tablet
• Touchscreen
• Barcode reader
• Image scanner
• Microphone
• Webcam
• Game controller
• Light pen
• Scanner
• Digital camera

Input Devices

In computing, an input device is a peripheral (piece of computer hardware equipment) used to provide data and control signals to an information processing system such as a computer or other information appliance. Examples of input devices include keyboards, mice, scanners, digital cameras , joystics etc.

Keyboard

• One of the primary input devices used with a computer.
• The keyboard looks very similar to the keyboards of electric typewriters, with some additional keys.
• Keyboards allow a computer user to input letters, numbers, and other symbols into a computer
• Uses an arrangement of buttons or keys
•  Requires pressing and holding several keys simultaneously or in sequence.

Type of Keyboard

• Standard
• Laptop
• Gaming and Multimedia
• Thumb-sized 
• Virtual
• Foldable

Standard

• Desktop computer keyboards, such as the 101-key US traditional keyboards or the 104-key Windows keyboards, include alphabetic characters, punctuation symbols, numbers and a variety of function keys.

Laptop Keyboard

• The laptop computer keyboard is a small version of the typical QWERTY keyboard.

• A typical laptop has the same keyboard type as a normal keyboard, except for the fact that most laptop keyboards condense the symbols into fewer buttons to accommodate less space.

Gaming and Multimedia Keyboard

The gaming keyboards are designed for the convenience of the gamers and these types of keyboards provide the required controls on the keyboards like back lighting.

Thumb -sized keyboard

• Smaller external keyboards have been introduced for devices without a built -in keyboard, such as PDAs, and smartphones.
• Small keyboards are also useful where there is a limited workspace.

Virtual Keyboard

• The virtual keyboards are not actually physical keyboards, but they are simulated using a software.

• Virtual keyboards allow computer use by people with significant mobility impairments. Some virtual keyboards incorporate word prediction to increase entry speed.

Foldable Keyboard

• Foldable keyboards are extremely good for travelling.
• Simply roll them up and then unroll them when you need them again. 

KEY TYPES

Function keys

• The Function keys or F1 through F12 keys are used in programs as shortcut keys to performed frequently performed tasks.
• For example, the F1 key is the key to open the online help for most programs.

Control Keys

• The Control keys are what give you additional control of a document.

Keypad

• Although not available on all computer keyboards, especially laptops; the keypad gives the user a quick access to numbers and math functions such as plus, divide, times, and subtract.

Arrow keys

• The arrow keys are four directional arrow keys that allow the user to move their cursor and position on a page. 

Keyboard Shortcut Keys

Pointing Devices

• A pointing device is a hardware input device that allows the user to move the mouse pointer to select items on a display screen.

Types of pointing device:

– Based on rolling a ball

– Based on touching a surface

– Based on moving stick 

Based on rolling a ball

• Example: – Mouse – Trackbal

Mouse

• A device that controls the movement of the cursor or pointer on a display screen.
• The mouse is important for graphical user interfaces because user can simply point to  options and objects and click a mouse button. 

             

Type of Mouse

• Mechanical: Has a rubber or metal ball on its underside that can roll in all directions.

• Optical: Uses a laser to detect the mouse's movement. 

Trackball

• A trackball is a mouse lying on its back.
• To move the pointer, you rotate the ball with your thumb, your fingers, or the palm of your hand
• It does not require much space to use it

Pointing Devices Based on touching a surface

• Example:

       – Touchpad

        – Graphic tablet

        – Touch screen

        – Light pen

        – Stylus

Touchpad

• A small, touch-sensitive pad used as a pointing device on some portable computers.
• By moving a finger or other object along the pad, you can move the pointer on the display screen. 

Graphic Tablet

• A graphics tablet (or digitizer, digitizing tablet, graphics pad, drawing tablet) is a computer input device that allows one to handdraw images and graphics, similar to the way one draws images with a pencil and paper.

Touchscreen

• A touchscreen is an electronic visual display that can detect the presence and location of a touch within the display area.
• The term generally refers to touching the display of the device with a finger or hand.

Light Pen

• A light pen is a computer input device in the form of a lightsensitive wand used in conjunction with a computer's CRT display.
• It allows the user to point to displayed objects or draw on the screen in a similar way to a touchscreen but with greater positional accuracy.

Stylus

• A stylus is a small pen-shaped instrument that is used to input commands to a computer screen, mobile device or graphics tablet.

Pointing Devices Based on Moving Stick

• Example: – Joystick – Gamepad

Joystick

• A joystick allows an individual to move an object in a game such as navigating a plane in a flight simulator. 

Gamepad

• A gamepad, game controller, joypad, or video game controller is a peripheral device designed to be connected to a computer or console gaming system.

• It has multiple buttons and may have one or two mini joysticks.

Imaging and Video Input Devices

• Used to digitize images or video from the outside world into the computer.

• Example: – Digital camera – Webcam – Optical scanner – 3D scanner – Fingerprint scanner – Barcode reader

Digital Camera

• A camera that stores the pictures or video it takes in electronic format instead of to film.

• Digital cameras have become the camera solution for most users today as the quality of the picture they take has greatly improved and as the price has decreased.

Webcam

• A webcam is a hardware camera connected to a computer that allows anyone connected to the Internet to view either still pictures or motion video of a user or other object.

Optical Scanner

• An optical scanner is a hardware input device that allows a user to take an image or text and convert it into a digital file, allowing the computer to read or display the scanned object.

• Two types of scanner:

– Flatbed

– Hand-held

Image Scanner

Flatbed Scanner	Handheld Scanner
Flatbed scanners look similar to a small photocopier with the document remaining flat and stationary during the scanning	Hand-held scanners are used for entering text and images that are less than a page wide. Handheld scanners are adequate for small pictures and photos but are difficult for entire pages.

3D Scanner

• A 3D scanner is a device that analyzes a real-world object or environment to collect data on its shape and possibly its appearance (i.e. color).

• The collected data can then be used to construct digital, three dimensional models.

Fingerprint Scanner

• A fingerprint scanner or fingerprint reader is a hardware device that verifies a user or enters password information by scanning their finger.

Barcode Reader

• A barcode reader or scanner is a hardware device capable of reading a barcode and printing out the details of the product or logging that product into a database.

Audio Input Devices

• Audio input devices allow a user to send audio signals to a computer for processing, recording, or carrying out commands.

• Example:

– Microphone

– MIDI keyboard

Microphone

• A microphone is a hardware peripheral that allows computer users to input audio into their computers.

MIDI Keyboard

• A MIDI (Musical Instruments Digital Interface) keyboard is typically a piano-style user interface keyboard device used for sending MIDI signals to a computer.

• MIDI information is sent to a computer that capable of reproducing an array of digital sounds or samples that resemble traditional analog musical instruments.

Output Device

• Any peripheral that receives or displays output from a computer.
• Computer hardware equipment used to communicate the results of data processing carried out by a computer to the outside world.

Examples of Output Device

• Monitor
• Printer
• Speakers
• Projector

Monitor

• The device which displays computer output.
• The monitor displays the video and graphics information generated by the computer through the video card.
• Monitors are very similar to televisions but usually display information at a much higher resolution.

Monochrome Monitor

• A monochrome monitor is a type of CRT computer display which was very common in the early days of computing, from the 1960s through the 1980s, before color monitors became popular.
• They are still widely used in applications such as computerized cash register systems
• Monochrome monitors actually display two colors, one for the background and one for the foreground.
• The colors can be black and white, green and black, or amber and black. 

Color Monitor

Color monitors can display anywhere from 16 to over 1 million different colors.
Color monitors are sometimes called RGB monitors because they accept three separate signals -- red, green, and blue. 

Types of Monitor

• Cathode Ray Tube (CRT)
• Liquid Crystal Display (LCD)
• Light-emitting Diode (LED)

Cathode Ray Tube (CRT)

?Large  Heavy Produce heat Not expensive

Liquid Crystal Display (LCD)

Less space  Lighter  Low power consumption  Expensive  Limited viewing angle

Light-emitting Diode (LED)

Less space  Lighter  Very expensive  Provide higher contrast and better viewing angles than LCD monitor

Printer

Printer is an external hardware device responsible for taking computer data and generating a hard copy of that data.

Printers are one of the most used peripherals on computers and are commonly used to print text, images, and photos.

Types of Printer Printers can be categorized into:

• Impact Printer
• Non-Impact Printer

Impact Printer

It strikes paper and ribbon together to form a character, like a typewriter.

Advantages	Disadvantages
Less expensive Can make multiple copies with multipart paper	Noisy Print quality lower in some types Poor graphics or none at all Slow

Examples of Impact Printers

Impact Printer Daisy-wheel

Similar to a ball-head typewriter, this type of printer has a plastic or metal wheel on which the shape of each character stands out in relief  A hammer presses the wheel against a ribbon, which in turn makes an ink stain in the shape of the character on the paper.  Daisy-wheel printers produce letter-quality print but cannot print graphics.

Impact Printer - Dot Matrix

Creates characters by striking pins against an ink ribbon. Each pin makes a dot, and combinations of dots form characters and illustrations.

 

Non - Impact Printers

• It uses ink spray, toner powder or inkless

Advantages	Disadvantages
Quiet Can handle graphics and often a wider variety of fonts than impact printers Fast	More expensive Occupies a lot of space The cost of maintaining it is high

Examples of Non - Impact  Printer

Non - Impact Printer - Laser Printer ( Toner Based)

A laser printer rapidly produces high quality text and graphics. Laser printers are often used in corporate, school, and other environments that require print jobs to be completed quickly and in large quantities.

Non - Impact Printer - Multiplefunctional Printer ( Toner Based)

An MFP is an office machine which incorporates the functionality of multiple devices in one. A typical MFP may act as a combination of some or all of the following devices: – Printer – Scanner – Photocopier – Fax

Non Impact Prinetr - Inkjet Printer

Inkjet printer operates by propelling variably-sized droplets of liquid or molten material (ink) onto almost any sized page.  They are the most common type of computer printer used by consumers.

Non Impact Prinetr - Thermal Printer

Thermal printers work by selectively heating regions of special heatsensitive paper. These printers are commonly used in calculators and fax machines; and although they are inexpensive and print relatively fast, they produce low resolution print jobs.