Input and Output Devices

Input Devices

In Computer, an input device is a piece of computer hardware equipment used tO provide data and control signals to an information processing system such as a computer or information appliance.

Examples of input devices include keyboards, mouse, scanners, digital cameras, joysticks, and microphones.

1 - Keyboard:-

The keyboard looks like a typewriter; kind of Input device.

The characteristics of Keyboard are : 

* It contains all the letters of the alphabet, numbers and some special symbols.

 *On key press it sends a code (ASCII (American Standard Code for Information Interchange) to CPU

2 - Mouse

This is a device used to control a computer like an input device.

The characteristics of mouse are...

A cabie Connects the mouse to the Computer When the mouse is moved On pad the cursor moves on the screen. It provides oints & Click with two Buttons and wheel.

Normally Left Click for Select/Run and Right click to generate Menu.

3 - Scanner : 

Scanners are used to enter information directly into the computers memory. This device works like a Xerox machine.

4 - Track Ball :

Track ball is similar to the upside- down design of the mouse. The user moves the ball directly, while the device itself remains stationary.

5 - Joystick:

Joystick is a kind of input device what is used to give an input to the computer system. That is mostly used in Game applications.

6 - Light Pen:

This is an input device which is used to draw lines or figures on a computer screen. It's touched to the CRT screen where it can detect raster on the Screen as it passes.

7 - OCR - (0ptical Character Reader):

It's an input device which detects alphanumeric characters printed or written on a paper. The text which is to be scanned is illuminated by a low frequency light source.

8 - Microphone :

It is a kind of Input device which is used to take sound as input. we do connect it with the jack port of the computer system at the front or rear panel of the system and use it.

9 - Biometric Sensor :

A Biometric Sensor is a device (or a transducer, to be specific) that converts the biometric trait of an individual into electrical signals. 

There are many types of Biometrics and coresponding Biometric Sensors used today like Fingerprint,Face. Iris, Speech, Hand Geometry, signature verification etc.

10 - Bar Code Reader : 

This device reads bar codes and coverts them into electric pulses tobe processed by a computer. A bar code is nothing but data coded in form of light and dark bars,

11 - MICR (Magnetic Ink Character Reader): 

It is kind of input device which is used to read magnetic characters from a page like on a bank cheque some magnetic charecters are used which can only be read by MICR.

12 - Touch Screen - 

The touchscreen is an input and output device. The display is often an LCD or LED display while the system is usually a laptop computer, tablet, or smartphone.

13 - Graphics Tablet : 

A graphics tablet (also known as a digitizer, drawing tablet, drawing pad, digital drawing tablet, pen tablet, or igital art board) is a computer input device that enables a user to hand-draw images, animations and graphics, with a special pen-like stylus, similar to the way a person draws images with a pencil and paper.These tablets may also be used to capture data or handwritten signatures.

14 - OMR : 

0ptical mark recognition (also called optical mark reading and OMR) is the process of capturing human-marked data from document forms such as surveys and tests. They are used to read questionnaires, multiple choice examination paper in the form of lines or shaded areas.

15 - Web Camera: 

Webcam is a digital camera that's connected to a computer. It can send live pictures from wherever it's sited to another location by means of the internet. Some webcam are plugged into computers through USB ports, but others are wireless (wifi). A Logitech Webcam C270, an example of a webcam. 

Output devices :

Output Devices give result either in hard or soft form. The devices which are used to display the data to the user either in the form of hard copy or soft copy are called output devices. 

The example: of Output devices are Screen/monitor, Printer, plotter, projectors speaker, Headphones.

1 - Monitor :

This is an Output device. VDU is a Visual soft Output device and used for the getting soft visual Output on screen. It measured diagonally from one corner of the screen to the opposite corner. VDU can be categorised into two types on the basis of technology the first one is CRT and second is LCD.

(i) CRT ( Cathode Ray Tube)

This is television like screen where the results of  a computer's takes are displayed. In this technology cathode ray falls on florescence screen and by deflecting rays make pictures. 

(ii) LCD (Liquid Cristal Display):

This VDU is thin flat and having light modulating technology. It is of two types:

TFT (Thin Film Transistor) It is a variant of LCD and makes matrix but not self lighting.

LED (Light Emitting Diode) Itis self back light emitting technology; picture quality is better.

2 - Printer:

A printer is an 0utput device that prints text documents, images, spread sheet etc as hard copy. Printer's quality is measured in dot per inch (DP). There are two types of printer Impact Printer and Non-Impact.

(i) Impact Printer: 

This type of printers strike against the ink ribbon and make impression on the paper. There is a metallic or plastic head having pins (nine pin or 24 pin head in dot matrix) or symbol and characters (in daisy wheel printer).

Dot matrixPrinter :

A dot matrix printer creates characters by striking pins against ink ribbons. Each pin makesa dot and combinations of dots from characters and illustrations. This is much like a typewriter. Each character is made from a matrix of dots.

(ii) Non-Impact Printer:

In this technology there is no any hammer to strike against ribbon. This is latest technology. The two main types of non impact printers are...

Inkjet Printer-

In this technology lonized Ink" spraying through magnetic plates on the sheet and making the symbol, image or documents. These printers produce high quality printings. This allows a print quality of 300 dpi or more to be printed.

Laser Printer

In this tecnnology as paper passes through the printer, the laser beam fall at the surface of a cylindrical drum called a photoreceptor. This drum has an electrical Positive charge, by reversing the charge in certain areas of the drum, the laser beam print patterns (such as text and image) onto the photoreceptor.

3D Printer

As the name implies, a 3D printer allows users to print an object as 3-Dimensional CAD (Computer Aided Design) images. Also called as additive manufacturing, 3D printing is an innovative technology that helps businesses cut costs and develop new methods of production.

4 - Multimedia Projector :

Projector is output device and often used in meetings presentations. It contains a lens inside which is used to flash the film to an object.

5 - Plotter :

Plotter is an output device that is used to produce graphical outputt on papers. It uses single colour or multi colour pens to draw pictures as blue print etc 

6 - Speech Synthesizer :

Speech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech computer or speech synthesizer. A speech synthesizer is a computerized device that accepts input, interprets data, and produces audible language.

7 - Speaker

Speakers are also kind of output devices which is used to play a sound as output it is used in multimedia applications to play or listen to sound or music.