Module 3

• Types of hardware

  • Input
  • Output
  • Memory
  • Storage
  • Processing
  • Communication
• Input devices


  • Keyboards
  • Pointing devices (mouse)
  • Touchscreens
  • Touchpads
  • Tablet/pen input devices
  • Game controllers
  • Cameras
  • Microphones
  • Video capture devices
  • Scanners
  • Optical readers
  • Biometric devices
  • Data collection devices
• Keyboard

  • Most computers come with a keyboard supplied
  • People are used to using keyboards to enter data, they need very little training
  • A skilled typist can enter data very quickly
  • Specialist keyboards, such as, ergonomic or gaming keyboards, are available
  • It is easy to make mistakes when typing in data
  • If you can't touch type, it can be time consuming to enter data
  • Disabled people often find keyboards difficult to use
  • Excessive use can lead to health problems, such as, repetitive strain injury (RSI)
• Mouse


  • Ideal for desktop and laptop computers
  • Most computer users are familiar with them and require little training
  • Works well in conjunction with a keyboard for data entry
  • Usually supplied as part of a new computer system
  • They need a flat space close to a computer to operate
  • Older style mice, which have roller balls, can become clogged with grease and grime and lose their accuracy until cleaned
  • Excessive use can lead to health problems, such as, repetitive strain injury (RSI)
  • If the battery wears out in a wireless mouse, it cannot be used until it has been replaced
• Touchscreens


  • Easy to use – intuitive, don't need much training
  • No extra peripherals such as a mouse are needed
  • Software can alter the screen while it is being used, making it more flexible than a concept keyboard which has a permanent overlay
  • Can make use of finger gestures to make sophisticated actions such as zooming and selecting
  • Excellent for selecting and controlling applications that have been designed with a touch screen in mind
  • Not suitable for inputting large amounts of data
  • Not very accurate – selecting detailed objects can be difficult with fingers
  • Tiring to use for long periods
  • Less useful as a control input to a standard computer that makes use of the mouse/keyboard combination, for example, laptop, desktop, pc
• Touchpads


  • Useful for laptops when using a mouse isn't practical
  • The pad's position is fixed in relation to the keyboard
  • Very short finger movements are required to move the cursor
  • Takes practice and skill to control the position of the cursor using the touchpad
  • Moist, sweaty or calloused fingers can disrupt the signals picked up by the sensors
• Tablet/pen input device


  • Tablets are easy to handle
  • It is much more natural to draw diagrams with a pencil type implement (the stylus) rather than with a mouse
  • A great level of accuracy can be achieved
  • Weaker capabilities than a laptop or desktop
  • The screen size is small
  • Fewer ports
  • No fixed keyboard
• Types of input devices


  • Game controllers
  • Cameras
  • Microphones
  • Video capture devices
  • Scanners
  • Optical readers
  • Biometric devices
  • Data collection devices
• An output device is any device that takes data stored on a computer and makes it available to the user in an easy to understand way
• Types of output devices


  • Display devices (monitors, LCD, LED)
  • Printers (Inkjet, Ink tank, Laser, 3-D)
  • Data projectors (HDMI, VGA)
  • Speakers
• Monitors

  • Number of pixels
  • Screen size
  • Refresh rate
  • Contrast ratio
  • Aspect ratio
  • Brightness
• Types of printers

  • Dot-matrix printers
  • Ink-jet printers
  • Laser printers
• Dot-matrix printers use a series of small pins to strike a ribbon coated with ink, causing the ink to transfer to the paper at the point of impact
• Inkjet printers operate by painting an image using a spray of ink through hundreds of tiny nozzles that spray drops of ink directly onto the paper while moving across it
• Laser printers use a laser to attract toner to the paper, which is then fused onto the paper using heat
• Main types of printers

  • Dot-matrix printers
  • Ink-jet printers
  • Laser printers
  • Ink-tank printers
  • 3D printers
• Dot-matrix printers


  • Use a series of small pins to strike a ribbon coated with ink, causing the ink to transfer to the paper at the point of impact
  • Mostly outdated as a personal printer but still used in banks and manufacturing businesses where it is necessary to use carbon paper to produce multiple copies of a document
• Ink-jet printers


  • Operate by painting an image using a spray of ink through hundreds of tiny nozzles that spray drops of ink directly onto the paper while moving across it
  • There are two types: continuous printers used for commercial purposes and on-demand printers
  • Good, all-round printer that is most commonly used for smaller jobs but slightly less reliable
• Laser printers


  • Use electrostatic technology: the drum is given a positive electrical charge, the printer shines a narrow laser beam over its surface to draw the letters and images as a pattern of electrical charges, toner sticks to the charged areas, and the image is 'burned' into the paper with heat and pressure
  • Used for mass production printing because they are generally faster and more reliable but with worse quality prints
• Ink-tank printers


  • Have print heads built into the printer and use an integrated bulk ink system, meaning ink is supplied continuously to the print head from an ink tank within the printer itself, no expensive cartridges are needed
  • When the ink is finished, it can be refilled from an ink bottle, producing low-cost, high volume printing
• 3D printers


  • A process of making three dimensional solid objects from a digital file by laying down successive layers of material until the object is created
• Factors to consider when looking for a printer

  • Whether it is black and white and/or colour
  • How quickly it can print
  • How much it costs to print a page
• Dots per inch (DPI)


  Measures how many dots a printer can print in one inch (or 2.54 cm), the higher the DPI the more detailed the prints
• Pages per minute (PPM)


  Measures how many pages of black text a printer can print in a minute, the higher the PPM the faster the printer can print
• Projector


  A device that uses a bright light to project the content displayed on a computer monitor onto any flat surface
• Types of cables connecting video output devices

  • VGA (analog video-only connection)
  • HDMI (digital video audio connection)
• Advantages of projectors


  • They are easy to carry around
  • They display the content from your computer at a large size
• Disadvantages of projectors


  • Replacing the lamps is expensive
  • Low-quality projectors can show washed-out or faded images
  • Low-brightness projectors need to be placed close to the screen, decreasing the size of the image
  • Low-brightness projectors may require a dark room
• Lumens


  Measures the brightness of the projector
• Resolution


  Determines how many pixels can be displayed
• Contrast ratio


  Measures the difference between the darkest and lightest parts of the image (the contrast)
• Advantages of speakers


  • They can be useful for alerting computer users of events using audio notifications, even when they're busy
  • Text can be converted into sound
• Disadvantages of computer speakers


  • They can take up a fair amount of desk-space, compared to headphones
• Types of headphones

  • Closed-back headphones
  • In-ear headphones
  • Bluetooth headphones
• Closed-back headphones


  Create an isolated audio experience so that only you can hear the sounds you want to hear
• In-ear headphones


  Known for portability, versatility, and convenience, they go a little more deeply into the ear to provide comfort, sound isolation, and sound accuracy
• Bluetooth headphones


  Offer wireless connectivity to various devices through radio transmitter technology (RF), they have a small computer chip inside that allows you to pair with the device you are playing music from
• Input/output device


  Any hardware used by a human operator or other systems to communicate with a computer, capable of sending data (output) to a computer and receiving data from a computer (input)
• Interactive whiteboard


  A board that combines the technologies of a computer, touchscreen, projector and whiteboard, can be connected to laptops, PCs, tablets, or other electronic devices
• When used in a classroom environment, interactive whiteboards give learners and teachers opportunities to interact more than the traditional blackboard ever could