Computer Notes on Input & Output Devices

Notes on Input & Output Devices

• Keyboard- The most common and very popular input device which helps in inputting data to the computer
• Mouse- Mouse is the most popular pointing device and cursor-control device having a small palm size box with a round ball at its base which senses the movement of mouse and sends corresponding signals to CPU when the mouse buttons are pressed.
• Joy Stick- To move cursor position on a monitor screen. It is mainly used in Computer Aided Designing (CAD) and playing computer games.
• Light pen- It is used to select a displayed menu item or draw pictures on the monitor screen.
• Track Ball- Mostly used in notebook or laptop computer, instead of a mouse .This is a ball which is half inserted and by moving fingers on ball, pointer can be moved
• Scanner- A scanner allows you to scan printed material and convert it into a file format that may be used within the PC.
• Digitizer- It converts analog information into digital form.
• Microphone-Microphone is an input device to input sound that is then stored in digital form.
• Magnetic Ink Character Recognition (MICR)- MICR input device is generally used in banks because of a large number of check to be processed every day.
• Optical character recognition (OCR)- OCR scans text optically character by character, converts

Output Devices: (How it shows you what it is doing) Output devices translate the computer's output into the form understandable by users.

Monitors: Monitors, commonly called as Visual Display Unit (VDU) are the main output device of a computer. It forms images from tiny dots, called pixels that are arranged in a rectangular form. The sharpness of the image depends upon the number of pixels.

There are two kinds of viewing screen used for monitors.

• Cathode-Ray Tube (CRT): The CRT display is made up of small picture elements called pixels. The smaller the pixels, the better the image clarity, or resolution
• Flat- Panel Display: The flat-panel display refers to a class of video devices that have reduced volume, weight and power requirement in comparison to the CRT.

Printer: Printer is an output device, which is used to print information on paper.

• Impact Printers: The impact printers print the characters by striking them on the ribbon which is then pressed on the paper.
• Non-Impact Printers: Non-impact printers print the characters without using ribbon. These printers print a complete page at a time so they are also called as Page Printers. Laser Printers, Inkjet Printers.