Parts of a Computer

• • Motherboard
  • The main circuit board inside a computer
  • It has lots of tiny copper lines on it which carry the electric signals around it and between components
  • It has all the main electronic components attached to it including the processor and the main memory
• • Processor
  • This is the brain of the computer
  • It is a tiny chip attached to the motherboard
  • It carries out all the instructions inside the PC (instructions are all in binary)
  • The faster the processor the faster the computer and its speed is measured in gigahertz
  • Processor speed is referred to as clock speed and measured in Hertz
• PROCESSOR

  • Everything the processor does happens at the tick of the tiny Quartz clock inside it
  • Faster clock means a faster processor as more instructions are fetched, decoded and executed per second
  • One clock cycle per second = 1 Hertz
  • Typical speeds are between 2 and 4 Gigahertz (between 2 and 4 billion instructions per second)
• MEMORY

  • Main memory is made up or read-only memory (ROM) and random access memory (RAM)
  • Data is stored in individually addressable memory cells
  • The computer can work out what an individual memory address contains by a process known as reading
• MEMORY

  • The contents of a memory cell can be changed by writing
  • RAM is where programs and data are stored whilst running
  • When the PC is switched off RAM is empty
• -HARD DISK-

  • This is a magnetic disk in a sealed case which stores all the programs and data needed by the computer
  • Data can be written to and read from the hard disk
  • It is in the form of one or more magnetic disks with a moving read/write head that reads the data stored in tracks and sectors on the disk
  • This is much slower to access than RAM so when the computer is running it loads data and programs from the hard disk to RAM
• • Graphics card
  • This is a separate circuit board that allows the computer to represent graphics on screen
  • It fits into an expansion slot on the motherboard
  • Sometimes they have their own RAM and processor built in
• • Sound card

  • This is a separate circuit board which allows the computer to produce sound output
  • Sound cards are installed inside an expansion slot on the motherboard
  • Without a sound card a computer will not be able to produce audio / sound