Components of Computer

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Components of a computer system are the primary elements which make the functioning of an electronic device smooth and faster.

There are basic components of computer system

  1. Input Unit
  2. Output Unit
  3. Memory Unit
  4. Control Unit
  5. Arithmetical and Logical Unit

Input Unit: External devices such as keyboards, mice, disks, and networks that provide input to the processor. Input Device is Device by which we can input our data or instructions into Computer. Computer has many Input Device, it directs the brain to Devices Computer, what does it do?

There are several types of Input Device, which are as follows -

  1. Keyboard
  2. Mouse
  3. Joystick
  4. Trackball
  5. Light pen
  6. Touch screen
  7. Digital Camera
  8. Scanner
  9. Digitizer Tablet
  10. Bar Code Reader
  11. OMR
  12. OCR
  13. MICR
  14. ATM etc

In short, an input unit performs the following functions.

  1.     It accepts (or reads) the list of instructions and data from the outside world.
  2.     It converts these instructions and data in computer acceptable format.
  3.     It supplies the converted instructions and data to the computer system for further processing.

Output Unit: Output Device is a device that provides data input by User as Result.The results obtained from the computer are achieved by the Output Device, these results are usually presented to the user by the display device (screen) or the printer.

Output Device is of several types like -

  • Monitor
  • Printer
  • Plotter
  • Projector
  • Sound Speaker

In short, the following functions are performed by an output unit.

  1.     It accepts the results produced by the computer which are in coded form and hence cannot be easily understood by us.
  2.     It converts these coded results to human acceptable (readable) form.
  3.     It supplied the converted results to the outside world.

Memory Unit: It stores the instructions received by Input Device in the computer, where it also goes to the memory of Computer. In humans, there are many things to remember, so are memory. This memory is integral to C.P.U., it is a storage device. Therefore, it is also called main memory of computer, internal memory, or primary memory.

"The location of the computer where all the information, instructions are stored"

Control Unit: The main unit inside the computer is the CPU. This unit is responsible for all events inside the computer. It controls all internal and external devices, performs “Arithmetic and Logical operations”. The operations a Microprocessor performs are called “instruction set” of this processor. The instruction set is “hard wired” in the CPU and determines the machine language for the CPU.

Arithmetic and Logic Unit (ALU): The arithmetic and logic unit (ALU) of a computer system is the place where the actual execution of the instructions take place during the processing operations. All calculations are performed and all comparisons (decisions) are made in the ALU. The data and instructions, stored in the primary storage prior to processing are transferred as and when needed to the ALU where processing takes place. No processing is done in the primary storage unit. Intermediate results generated in the ALU are temporarily transferred back to the primary storage until needed at a later time. Data may thus move from primary storage to ALU and back again as storage many times before the processing is over.


Notes: The control Unit and the Arithmetic and Logic unit of a computer system are jointly known as the Central Processing Unit (CPU). The CPU is the brain of any computer system. In a human body, all major decisions are taken by the brain and the other parts of the body function as directed by the brain. Similarly, in a computer system, all major calculations and comparisons are made inside the CPU and the CPU is also responsible for activating and controlling the operations of other units of a computer system.

1.Getty Images, Inc., is a British-American: Image Components of Computer
2. Bytenotes Memory, CPU