Input & Output Devices

Input & Output Devices Of a Computer

• INPUT DEVICES 

Data and instructions are entered into a computer through input devices.
 An input device converts input data and instructions into a suitable binary form, which is stored in main memory of a computer.

1. Keyboard 

Computer keyboard is an electromechanical component. It Creates special standardized electronic codes when a key is pressed. The codes are transmitted along the cable that connects the keyboard to the computer system unit or terminal, where the incoming code is analyzed and converted into the appropriate computer usable code. Keyboards come in a variety of sizes and shapes having a number of features in common.

2. Mouse

The mouse is an input device that is much in use nowadays in graphics as well as when working with the GUI (Graphical User Interface). It slides on a rubber ball in mechanical mouse and laser rays in optical mouse, and has two or more button on the top. when a mouse is slid across a flat surface, the screen cursor also moves in the direction of the movement of the mouse. With a click of the button, the system can be notified of the selected position. 

3. Joystick

A Joystick is a pointing device used to move the cursor position on the screen. It has a spherical ball at its lower end as well as at its upper end. The lower spherical ball moves in a socket. The joystick can be moved right or left, forward or backward. It is mostly used in Video Games.

4. Scanners

These are basically input devices that are capable of recognizing marks or characters. They are used for direct entry of data into the computer. Reduction in human intervention improves data accuracy. Since scanners are direct data entry devices, so they demand high quality  documents.

5. MICR (Magnetic Ink Character Recognition)

Magnetic Ink Character Recognition devices were developed to assist the banking industry. it is used in the processing of cheques. The most commonly used character set by MICR devices is known as E13B font that consist of numerals 0-9, and 4 special characters. These help in sorting of cheques/drafts based on the code printed on the cheque using the E13B font.
Processing is speed ed up using MICR but the main limitation is that only 10 digits and 4 characters are used. 

6. OMR (Optical Mark Reader)

  Optical Mark Readers are scanners used for recognizing a pre-specified type of mark made by pen or pencil on specially designed sheets. These scanners are mostly used in evaluating objectives type examinations.
Checking presence or absence of mark at definite position does the grading.

7. Bar Code Reader

 Data coded is in the form of light and dark lines or bars are known as bar codes.
Particularly the retail trade for labelling goods uses bar codes. Bar Code reader is a device used for reading bar coded data.
Bar Code reading is performed by a laser-beam scanner, which is linked to a computer.

• OUTPUT DEVICES 

1. Monitors

This is the most popular Input Output device used in nowadays for interactive processing.

A keyboard is used to enter data into a processor and a video display unit called monitor is used the keyed data and to receive processed information and messages from the computer.

2. Printer

Printer are primary output devices used to prepare permanent documents for human use.

Printers, on the basis of technology used in them, can categorised as:

• Impact Printers - These operate like a typewriter, pressing a typeface against paper and linked ribbon. e.g. Daisy wheel printer, Dot-matrix printer.

• Non-Impact Printers - These use thermal, electrostatic, chemical, and ink jet technologies.

3. Speakers 

Computers produce audio data that requires output devices such as speakers and headphones to deliver the sound to you. Audio data is created by the computer and then sent the audio card, which is located in an expansion slot. the card translates the data into audio signals, which are sent to the audio output device.(source techwalla.com)

4. Projectors 

The projectors are output devices, this is also called display devices which shows output to the user in the form of images,videos or presentations.

5. Plotter

Plotter is One of the most popular output device. plotter create hard copy of a graphic designs. plotter generally used in engineering applications to draw designs by pen. 

These are some I/O devices of a computer, Hope this is helpful to you...

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