Input Devices (How to tell it what to do): This unit makes a link between user and computer. The input devices translate the information into a form understandable by the computer.
- 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 the mouse and sends corresponding signals to the 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 that is half inserted and by moving fingers on the ball, the 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 analogue 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 checks to be processed every day.
- Optical character recognition (OCR)- is a method of converting a scanned image into text.
Output Devices: (How it shows you what it is doing) Output devices translate the computer's output into a form understandable by users.
Monitors: Monitors, commonly called 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 screens 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: A 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 a ribbon. These printers print a complete page at a time so they are also called Page Printers. Laser Printers, Inkjet Printers.
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