Computer hardware

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Computer hardware refers to the physical parts in a computer system, as opposed to software which is executed within it. Hardware is changed less often than software which can be changed or removed quickly and easily on a computer. Hardware components connect to the central processing unit (CPU) through special sets of wires known as buses. Processing speeds and storage capacities of hardware components are continuously increasing while costs are falling.

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List of computer hardware

The following are the main hardware components of a personal computer:

  • Motherboard: Also called a system board, the motherboard is a circuit board placed inside the chassis. The following parts are fixed on the motherboard:
    • Central processing unit (CPU): This is the main component of the computer that controls the computer's hardware and software.
    • Random access memory (RAM): RAM is the volatile memory in a computer on which data is stored in a random manner.
    • Buses: These are data channels that transfer data or power in computer systems usually between the CPU and an external device. Examples include PCI, AGP and USB.
    • Expansion cards: These include modems and Ethernet cards.
  • Power supply unit (PSU): This device installed inside the chassis converts AC current into DC currents required by various components.
  • Video display controller: This provides the video output to the monitor.
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Input

Input devices are used to enter data and instructions into the computer.

  • Keyboard: Keyboards are used for inputting text and controlling the computer.
  • Scanner: A scanner converts images into digital form so that it can be stored and manipulated by computers.
  • Microphone: This device is used for inputting audio in the computer.

The following input devices are known as pointing devices:

  • Mouse: A mouse is a device gripped by the hand that has a ball (or some other detection mechanism) at the bottom. A mouse can have either two or three buttons.
  • Trackball: Trackballs are like inverted mice and perform the same functions.
  • Light pen
  • Joystick
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Output

Output devices transfer information from the computer to the user. The following are some output devices:

  • Computer display: This device produces video output to the user of the computer. There are two main types of computer displays: CRTs (cathode ray tubes) and LCDs (liquid crystal displays).
  • Printer: This device is used to produce output on paper or similar media. Common types of printers are dot-matrix, laser and inkjet printers.
  • Speaker: Speakers are used for audio output.
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Storage

Storage devices include disk drives such as hard disks, floppies, CDs and DVDs and memory chips such as the RAM and ROM (read-only memory).

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