What does a PC do

1
What does a PC do?

• computers collect, process, store, and
  communicate information
• Collect via input devices mouse, keyboard,
  scanner, digital camera
• Process via CPU
• Store onto storage devices hard disk, CD ROM,
  tape drive
• Communicate via output devices monitor, printer,
  speakers, robot

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Input Devices
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Storage
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Output Devices
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Communications
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Important Units

• Bit (Binary Digit, 0 or 1) is the smallest unit
  of info a computer can process
• Byte is eight bits - amount needed to represent
  one alpha-numeric character.
• Kilobyte (KB) is 1024 bytes, roughly half a page
  of text
• Megabyte (MB) is 1024 kilobytes
• Gigabyte (GB) is 1024 megabytes

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Power Supply

• converts mains (AC) electricity to DC
• PC uses 200 Watts, one unit of electricity every
  five hours
• Fan prevents parts from overheating and keeps
  case size as small as possible
• Surge Protectors (optional) protect against
  voltage spikes
• Uninterruptable Power Supply (UPS, also optional)
  protects a computer from loss of power

8
Ports

• Connectors at the back of the computer where you
  plug in a peripheral device
• modem, printer, mouse, keyboard
• Serial ports have 9 pins
• Labelled COM1, COM2
• Connect to mouse or modem
• Parallel ports have 25 connections
• Labelled LPT1, LPT2
• Connect to printers or tape drives

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More Ports

• Keyboard ports
• Games ports
• USB - Universal Serial Bus
• allows several devices to be connected via only
  one port
• fast data transfer rate

10
Expansion Cards/Boards

• circuit boards that let you add a new feature to
  the computer
• PCs have a number of expansion slots
• Buy a PC with plenty of slots spare
• Most cards go into the motherboard
• Some plug into the back (Notebooks and Laptops)

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Types of Expansion Card

• Video - generates images to display on monitor
• Modem - allows computers to exchange information
  via telephone lines
• Sound - play and record audio
• Network - to allow connected computers to share
  information and peripherals