Output devices Tutorials point

Definition:

The information processed by a computer is translated into a form that we understand and displayed by these machines. Normally, the output is classified or manipulated as Softcopy output or Sound output and Hardcopy output.

Softcopy: 

It refers to data is shown on a display screen or is in an audio or voice form. This kind of output of our document that is not tangible; it cannot be touched but seen must. Virtual reality and robots might also be considered softcopy devices that represent on a screen.

 Hardcopy

It refers to printed output that prints a paper. The principal examples are printouts on a paper form, whether text or graphics, from printers and, plotters,  etc.

Display Screen:

It also is known as CRTs, Monitors, or simple screens, which differ in size color, resolution, and video display adapter card. 

Size:

Monitors come in different sizes from small screens of a display screen built into palmtops and laptops to extra large monitors used for special purposes in industry.

Color:

Many monitor display colors. These RGB (RED, GREEN, BLUE) displays can create 256 colors and several thousand variations on them by blending shades of Red, Green, and Blue (RGB). Monochrome displays show information using a single foreground color on contacting background color.

Resolution:

All the characters and images on a  monitor are made u of dot patterns; the number of dots, or pixels,  per inch, determines resolution, or the sharpness of the image. A higher number of pixels means a sharper image of a screen view.

Video display Adapters:

To display graphics, a  screen must have a video display adapter attached to the computer. It is known as a video graphics card that in a very video form, and is a circuit board that determines the resolution of the screen, the number of colors, and speed with which images appear on the display screen of the monitor screen.

Types of Video Display Adapters:

There are three types of video display adapters which are as follow:

• VGA:

VGA stands for Video Graphics Array, It supports 16-256 colors o a display screen, depending on screen resolution. At 320*200 pixels, it will support 16 colors on a display screen and at 640*480 pixels, It displays 256 colors. It is called a 4-bit color.

• SVGA:

Super Video Graphics Array, support 256 colors at a higher resolution than VGA. It has two graphics modes that represent on-screen mode. It has 800*600 pixels and 1024*768 pixels. It is called 8-bit color.

• XGA:

XGA stands for Extended Graphics Array, It supports up to 16.7 million colors at a resolution of 1024*768 pixels on a display screen. Depending on the video display adapter memory chip to display on the screen, XGA will support 256, 65536, or 16,777,216 colors to display on a screen.

It is called a 24-bit color or True color.

Types of Screen:

Display screens are of two types which are as follows:

1. CRT (Cathode Ray Tube)

The most common type of display screen is CRT (Cathode Ray Tube). A Cathode-Ray tube is a vacuum tube used as a display screen in a computer or video display terminal on a screen. This same kind of information technology display screen is found not only in the display screens of desktop computers but also in the television display screen set of vision and in the fight- information monitors at the airport. The stream of bit's defining the image is sent from the network computer system to the CRT's electron gun, where the bits are converted to electrons with a negative sign. The inside of the fronts of the CRT screen is coated with phosphor. 

2.Flat-Panel Display:

The flat-panel displays are much thinner in size, weightless, and consume less power to Cathode Ray Tube. Thus, they are better for portable computers network systems, Flat-panel displays are made up of two plates of glass that represent data with a substance in between them, which is activated in different ways in suitable ways. There are three types of technology used in flat-panel display screens which are as following to describe:

LCD (Liquid Crystal Display) consists of a substance called liquid crystal on a display screen of a required document, the molecules of which line up in a way that lighting behind the screen mode is blocked or allowed through to create an image. Electro- Luminescent Display contains a substance that glows when it is charged by an electric current on the display screen to view the document. 

Printers:

Printers are used to print characters, symbols, and graphics on paper which we required. They are divided into two types or categories:

• Impact Printers
• Non-Impact printers

An impact printer uses to print a document. Impact printers form characters or images on a soft copy with pixels by striking a mechanism on a document such as a print hammer or wheel against an inked ribbon leaving an image on the paper about a document to show our required images. Following are a few types of impact printers that are used for many purposes:

• Dot-Matrix printer:

It contains a print a paper head of small pins, which strike an inked ribbon against the paper or document, forming characters or images of pixels. Print heads are available with 9,18, or 24 pins that print paper, with the 24-pin head, offer the best quality print a document.

• Daisy-Wheel printer:

This printer uses a mechanism in the shape of a series of petals arranged on a petal wheel, having a character at the end of each Patel. A character or images comes into a print position by wheel rotation and an image with a pixel or resolution is formed by the hammer strike on the desired character.

• Line printer:

This type of printer is normally or essentially used by mainframe and minicomputers network systems. Some of these can print up to 3000 lines per minute to print a document as we want.

Non-Impact printers:

It forms characters and images with the best resolution to display on screen without making direct physical contact between the printing mechanism and paper. These are three types in this category.

• Laser printer:

It is as same as a photocopying machine and it uses the principle of dot-matrix printers of creating images with dots to represent a document. These images are created on a drum to give output, treated with a magnetically charged ink-like toner for output, and then transferred from drum to paper to show output.

• Ink-jet printer:

It is a type of printer to print a document that has four nozzles. It uses in many other  purposes

• Thermal Printer:

It uses colored waxes and heat to produce images by burning dots on special paper. The colored wax sheets are not required for the black-and-white output to the required image. It Produces high-quality printouts but is quite expensive compared to other non-impact printers. 

Plotters:

A plotter is used to produce high-quality graphics in many colors to display on a screen and used for specialized applications of computer network systems i.e. architecture drawings, maps, graphs, and charts. 

Two Types of Plotters:

Flatbed plotter:

A flatbed plotter is the type of plotter that has a paper lying flat sheet on a table-like surface. The bed-size varies according to the need. 

Drum plotter:

It works like a flatbed plotter with the difference that the paper is mounted over a drum, enabling continuous output. Typical usage is to track earthquake readings.

Sound output:

Speakers are most commonly used to have this type of output.