Computer Components


An input device sends information to a computer system for processing, and an output device reproduces or displays the results of that processing. Depending on the interaction, a device can be both, referred to as an input/output or I/O device.

Input Devices

* Graphics Tablets A graphics tablet consists of an electronic writing area and a special “pen” that works with it. Graphics tablets allow artists to create graphical images with motions and actions.
* Trackballs The trackball is sort of like an upside-down mouse, with the ball located on top.
* Joystick Joysticks and other game controllers can also be connected to a computer as pointing devices.
* Keyboard The computer keyboard is used to enter text information into the computer, as when you type the contents of a report.
* MIDI keyboard A MIDI musical keyboard can be attached to a computer and allow a performer to play the music that is captured by the computer system as a sequence of notes with the associated timing.
* Mouse (pointing device) The mouse pointing device sits on your work surface and is moved with your hand.
* Scanner A scanner is a device that images a printed page or graphic by digitizing it, producing an image made of tiny pixels of different brightness and color values.
* Touchpads You move the on-screen cursor by sliding your finger along the surface of the touchpad.
* Microphone A microphone can be attached to a computer to record sound.

Output Devices

* Monitor In computers, a monitor is a computer display and related parts packaged in a physical unit that is separate from other parts of the computer.
* Printers Multi-function printers are available that not only operate as a computer printer, but also include the hardware needed to be a scanner, photocopier, and FAX machine as well.
* Plotters A device that draws pictures on paper based on commands from a computer with a pen.
* Projector A device that projects computer output onto a white or silver fabric screen that is the wall, ceiling or tripod mounted.
* LCD Projection Panels An LCD projector is a type of video projector for displaying video, images or computer data on a screen or other flat surface.
* Speaker A device that converts analog audio signals into the equivalent air vibrations in order to make an audible sound.


Memory is an essential element of a computer. Without its memory, a computer is of hardly any use. Memory plays an important role in saving and retrieving data. The performance of the computer system depends upon the size of the memory.

Types of Memory
1. Primary Memory (Volatile Memory)
2. Secondary Memory (Non-Volatile Memory)

* Primary Memory Primary Memory is internal Volatile memory of the computer. Primary memory is computer memory that a processor or computer accesses first or directly. It allows a processor to access running execution applications and services that are temporarily stored in a specific memory location. Primary memory is also known as primary storage or main memory.

Types of Primary Memory
Random Access Memory (RAM), Read Only Memory (ROM), PROM, EPROM, Cache Memory, Registers

* Secondary Memory This type of memory is also known as external memory or non-volatile. It is slower than the main memory. These are used for storing data/Information permanently. CPU directly does not access these memories instead they are accessed via input-output routines. Contents of secondary memories are first transferred to the main memory, and then CPU can access it. For example disk, CD-ROM, DVD, etc.

Types of Secondary Memory
Magnetic Tape, Magnetic Disk, Optical Disk


CPU is the primary component of a computer that processes instructions. It runs the operating system and applications, constantly receiving input from the user or active software programs. It processes the data and produces output, which may be stored by an application or displayed on the screen.

Components of CPU
Arithmetic Logic Unit, Control Unit, Registers

Functions of CPU
Fetch, Decode, Execute, Store

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