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Unit 3 – External Hardware Peripherals

Items In This Unit

  • Computer Monitor / TV
  • Printer
  • Plotter
  • Scanner
  • USB Memory Sticks
  • USB WIFi Network Adapters
  • SD Cards & Readers
  • External Drives
  • Pointing Devices
  • Keyboard
  • Gaming Devices
  • Webcam
  • Speakers / Headphones
  • MIDI Keyboard
  • Network Router

Computer Monitor / TV

  • Computer monitor projects computer-generated images and videos.
  • Computer monitors come in various sizes anywhere from 5” to over 50”
  • Modern monitors support various screen resolutions including include: 1280×720 (720p), 1920×1080(1K), 2560×1440(2K), 3840×2160(4K)
  • Modern TVs can also be attached to computers and act like computer monitors


  • A printer is a peripheral device that creates a paper copy of computer text, images and graphics.
  • 3 types of printers still dominate the computing world
    • Dot Matrix printer applies ink via tiny rods striking an ink ribbon.
    • Ink-Jet printer recreates a digital image by propelling droplets of ink onto paper and plastic substrates.
    • A laser printer is a type of printer that produces high-quality text and graphics by repeatedly passing a laser beam

Printer Comparison

The following table provides a comparison between various printer types.                                                             


Printer Type



Dot Matrix Printer

InkJet Printer

Laser Printer

3D Printer












60 to 90 DPI

300 – 720 DPI

300 – 2400 DPI

Smallest – High



100 – 400 cps





30 min to
several days


Ink Ribbon

Ink Cartridge




Popular in the 90s

Very Popular


Gaining Traction


  • A plotter produces vector graphics drawings.
  • Plotters draw lines on paper using a pen.
  • Plotters use very large paper to plot engineering, architecture and other types of sophisticated drawings
  • Plotters are typically used by engineers, and architects utilizing AutoCAD or other computer-aided design software.


  • An image scanner or just scanner is a device that optically scans images, printed text, handwriting or an object
  • The scanner converts what it sees to a digital image or to text files using the OCR (Optical Character Recognition) software
  • Scanners are typically integrated into modern printers

USB Memory Sticks

  • A USB memory stick (or USB flash drive) is a data storage device that includes flash memory with an integrated USB interface.
  • Compared with floppy disks or CDs, they are smaller, faster, have significantly more capacity, and are more durable due to a lack of moving parts.
  • Most weigh less than 30 g (1 oz).
  • USB memory sticks come in various sizes up to 2 TB
  • Typically allow up to 100,000 writes/erase cycles.
  • Often used for storage, data back-up and transfer of computer files.

USB WIFi Network Adapters

The USB WIFI Network adapters:

  • Provide WIFI network connectivity
  • Useful when a wired connection is not possible
  • Can get a better WIFI signal than internal WIFI adapters
  • Portable
  • Can be used by multiple computers

SD Cards & Readers

  • Secure Digital (SD) is a proprietary non-volatile memory card format developed by the SD Card Association for use in portable devices as well as computers with the help of SD card readers
  • SD cards can store a similar amount of memory as their USB flash card counterparts (up to 2TB)
  • There are three main types in the SD memory card family. SD, SD High Capacity (SDHC™), and SD Extended Capacity (SDXC™)
  • Card readers come either as an internal or external peripheral

External Drives

  • External drives comprise devices that store information outside a computer.
  • External devices may be permanently attached to the computer, maybe removable or may use removable media.
  • External drives or devices include:
    • CD, DVD & Blue-ray external drives
    • IDE External Hard Drives
    • SSD External Drives
    • SSHD External Drives (hybrid SSD & IDE drives)

Pointing Devices

  • One of the most popular pointing devices is a computer mouse
  • Another common pointing device is a laptop touchpad
  • Trackballs are another popular pointing device
  • With the rise of mobile devices touch
    the screen has become the most popular
    pointing device


  • A computer keyboard is a typewriter-style device that uses an arrangement of buttons or keys to act as mechanical levers or electronic switches.
  • Desktops typically have more keys than their laptop counterparts
  • Most keyboards use a “QWERTY“ key arrangement

Gaming Devices

  • A game controller is an input device used with video games or entertainment systems to provide input to a video game, typically to
    control an object or character in the game.
  • Game controllers used with personal computers work the same way as game input devices for video game systems.
  • Game controllers are typically connected to a personal computer using the USB port


  • A webcam is a video camera that feeds or streams an image or video in real-time to another computer either on a local network or the Internet.
  • Webcams are typically small cameras that sit on a desk, attach to a user’s monitor, or are built into laptops.
  • New webcams come in 720p, 1k, 2k and higher quality

Speakers / Headphones

  • Computer speakers are typically a must-have peripheral to output computer sounds and music as most desktop computers do not come with speakers.
  • Laptops already come with built-in computer speakers but are typical of low sound quality.
  • Standard stereo headphones can be used with personal computers instead of computer speakers.

MIDI Keyboard

  • MIDI stands for Musical Instrument Digital Interface
  • MIDI is a standard adopted by the electronic music industry for controlling devices, such as synthesizers and sound cards, that create music.
  • A MIDI representation of a sound includes values for the note’s pitch, length, and volume.
  • MIDI keyboards allow musicians to create songs using a combination of computer programs along with an external MIDI keyboard attached to the USB port.

Network Router / Hub

  • A router is a networking device that connects computers to at least 2 networks and various computers.
  • A network hub is similar to a network router but it only operates on a single typically home or office network
  • The most common type of routers are home and small office routers
  • Most modern routers allow you to connect by a network cable or by WIFI.
  • Some internet routers provided by your internet provider also function as cable modems.

Unit Quiz:

Answer the following questions: 

  1. What is the name of a peripheral that creates engineering drawings?
  2. What kind of keyboard device can be attached to a computer to create music?
  3. Can a hard drive be attached externally? 
  4. Can you name one type of computer port that can help you store pictures on a particular external device?


Previous Unit 2 – Computer Internals
Next Unit 4 – Software

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