Output Devices

Monitor

printer

The device used for taking out information from a computer and presenting them in the desired form to the user. This is worked just in reverse manner that in input device such as printed form by printers, graphics formed by plotters, audible sounds from speech synthesizer etc. Generally there are two types of devices (based on output nature).
a. Softcopy Output Devices: The output devices which produce the temporary result to the user is termed as softcopy output devices such as monitor, speaker etc.
b. Hard Copy Output Devices: The output devices which produce the permanent result to the user is termed as as hardcopy output devices such as printers, plotters etc.

Output Devices:

Printer:

The device which has mechanism to produce the output on paper is termed as printer.

Types of Printer (Based on contact between paper and print head):

The printers broadly categorized into 2 groups based on printing mechanism as follows:

a. Impact Printer:

The impact printers transfer the image onto the paper by some type of printing mechanism striking the paper, ribbon, and character together, similar to a typewriter. The most common printer of this type is a dot-matrix printer.

a.      Non-Impact Printer:

The non-impact printers use a system where there is no mechanism used to strike a sheet of paper. Ink is sprayed onto the paper, or pressure and heat are used to transfer the image to paper.

Type of Printer (Based on Speed):

The printers broadly categorized into 3 groups based on printing speed as follows:

1. Serial or character printer:

Many small computers use character printers. This printer produces a character at a time on paper. The character printers can produce graphics as well as text. The most of the character printers create images or text by using a dot pattern. Its speed is quite low than other printers.

·        Dot matrix printer        

·        Daisy wheel printer

·        Golf Ball printer

·        Cylinder printer

2. Line Printer:

The printer prints a line at a time because of the print head is a cylinder extending he full width of the paper. At each column there is a full set of characters arranged in a circle around the cylinder. The cylinder revolves quickly, so that at each line it rotates one full revolution there is a hammer for each character, and by activating the hammers at the correct time, a full line of text can be printed in a single revolution of the head. The printers are faster than character printer.

• Chain Printer
• Band printer
• Drum Printer
2. Page Printer:

The printer transfers an image of text and picture on paper at a time. It is high quality and high speed printer.

Impact Printer:

1. Solid font: A complete character, such as on a typewriter key, strikes a carbon ribbon or other liked surface against paper to produce an image of character.
2. Dot matrix printer: The printer head is made up from pins which push out to give different patterns to produce text or graphics on paper. The dot matrix printers are very noisy.
3. Daisy wheel & Golf ball Printer: It is a solid font type character printer. The daisy wheel printer is so named because the printer heads resemble a daisy flower, with the printing arms appearing like the petals o the flower. This type is also produced as smart, bi-directional printers.
4. Line Printer: Line printers of Dot Matrix are always slow speed type. High-speed line printers use impact methods to produce line-at-a-time printed output. The speed of printing of this printer is 300 over 3000 lines per minute.

NON-IMPACT PRINTERS:

1. Laser Printer: A non-impact printer which uses a deflecting laser beam on to the photosensitive surface of a drum and the latent image attracts the toner to the areas. As heat and pressure is applied to the toner it is melted and pressed onto the paper to for a permanent image. The printers are quite expensive, speed and high quality printer.
2. Ink jet Printer: The ink jet printers create images by shooting tiny droplets of special links contained in cartridges at he paper. The aim of the spray is much more precise than the pins of a dot matrix printer, so the resolution of the image is far better. For top quality images such as photos, you can use special coated paper to give an almost photo quality image.
3. Electrostatic Printer: Electrostatic printers can also be used for graphics work as plotters, since any pattern cab be printed. The selected areas of a specially coated paper are exposed to high voltage and then to a colored toner which clings to those areas. The printer forms characters by impressing static charges of electricity on special paper.
4. Post Script Laser Printer: This printer has more option than a PCL printer when you are suing different color because of its professional quality. This printer is especially used in graphic arts studios.
5. Thermal-Wax Printer: A thermal wax printer produces sharp, rich colors non-smearing colors. This printer uses 3-4 full page color ribbons of wax. A heated print head melts the wax and places it on specially coated hat sensitive paper. This printer is used in high quality imagery and color overhead transparencies.
6. Dye Sublimation Color Printer: It is the highest quality graphic producing printer there is. This printer uses heat to transfer the ink from colored ribbons into a gas which turns into a glass like substance. This printer has such good graphics it is said to be photographic quality.
7. MICR Printer: The MICR printers provide a fully secure printing environment for you business. Signatures, logos, complex graphics and MICR numbering can all be printed in a single pass from one of at least 2 locked paper trays. Each MICR printer uses a 3 position key MICR printer also ensures maximum efficiency. If a paper jam occurs, built-in protection prevents the printing of a duplicate cheque etc. The MICR produces the highest print quality.

 Resolution:     A more numerical measure of print quality is printer resolution which is measured in dots per inch(dpi). The higher is DPI, better the printing quality.

Plotters: A plotters, like a printer, produces hard-copy output. Plotters, which produce high-quality color graphics, are usually categorized by whether they use pens or electrostatic charges to create images. A continuous curve plotter is used to draw maps from stored data. Computer-generated maps can be retrieved and plotted or used to show changes over time. Plotters are ideal for engineering, drafting, and many other applications that require intricate graphics. Plotters are generally more expensive than printers.

Types of Plotters:

1. Pen Plotters: The Pen plotters have an ink pen attached to draw the images and the quality of plotter is high.
2. Flatbed Plotter:  This  is  a   plotter  where  the   paper  is  fixed  on  a  flat   surface  and  pens  are  moved  to    draw  the  image .This  plotter    can    use   several    different   color    pens   to  draw   with. The  size  of  the  plot   is    limited   only  by  the  size  of  the  plotter's   bed.
3. Drum   Plotters: In drum  plotters the  pen  is moved  in  a  single  axis  track  and  the  paper  itself moves on a cylindrical  drum  to add  the  other  axis or dimension. The size of the graph is therefore limited only by the width of the drum can be of any length.
4. Electrostatic Plotter: An electrostatic   plotter produces a raster image by charging the paper with a high voltage. This voltage attracts toner which is then melted into the paper with heat. This type of  plotter  is fast, but  the  quality   is  generally  considered  to be  poor  when  compared to pen plotters. 

ROBOTS MACHINE

     The    robots  are  able  to perform  a variety of  tasks as  a result  of  executing  instructions  contained with  in a program. Robots in a business sense mean automated machines designed to perform mundane operations which require accuracy, such as assembling cars and computer assembly. They are seldom manufactured to resemble the human form.

Machine Tool

Computer Aided Manufacturing tools are used to manufacture a variety of products. Repetitive functions are controlled by sets of computer instructions. Machines tools automate factory production and have the advantage over humans of high accuracy, and they continuously fast.

Voice synthesis

The voice synthesis has a robotic sound due to the difficulties of replicating the complexities of human speech and pronunciation. Voice answer back is used to respond to telephone enquiries, such as the speaking clock. Educational applications include "Speak and Spell".

Speakers

Computers can output music and other sound using speakers. A special circuit board called a sound card is needed to enable the computer to communicate to the speakers to give an output. New computer systems have such good audio systems that it is possible to listen to music while you work, have the computer tell you when the printer needs paper, play games that include sound, or compose music on the computer.

LCD/Data projector

The output device gives every presenter a powerful tool to easily manage a meeting. A device is used for taking the information from the computer and projecting it onto a larger movie screen. The LCD and data projectors that operates easily on a table top for fast, fool proof set ups which projects work instead of displaying it on a monitor and can show a power point slide show, a web page, or other projects developed on the computer to a larger group of people.

Monitor

The monitor is primarily soft copy output device. The monitor provides a window through which the user can 'see' the programs executed. It converts electronic signals from the computer into a visual display that is the result of processing information. It can be thought of as a high resolution TV set. The monitor can also determine if the display will be color, black and white, or include graphical objects. The monitor displays ext and images converted to output from the video adapter. The adapter changes the instructions from the central processing unit into a way that the monitor can understand it.

Cathode Ray Tube(CRT)

A cathode ray tube screen is generally found in desktop workstations in the larger transportable PC models. A single gun in CRET sends a beam of electrons to trace a regular pattern of horizontal and vertical line on the phosphor that varying he intensity of the beam produces coats the screen's surface and produce images.

Flat panel displays

The smaller monitors that are used on laptops and notebook computers are known as flat-panel displays. These screens are created with a variety of technologies. The flat-panel displays weigh less and consume less electricity than CRTs. Flat-panel displays monitors are still more expensive than CRTs. The recent 16-inch flat-panel includes a two-million color palette and too expensive.

Liquid crystal display (LCD)

The screens use an entirely different technique. LCD displays are made of two layers of a polarizing material with a liquid crystal solution in between. An electrical signal makes the crystals line up in a way that keeps light from going through entirely or just partly. A black screen has uses groups of 3 color cells instead of 3 phosphor dots and the picture cleverly lets just the right spots show their color. He major advantage of LCD is the low energy consumption.

Flat screen

A display technology that used rod shaped molecules that flow like liquids and bend light. Un-energized, the crystals direct light though two polarizing filters, allowing natural background color to show.

Plasma display

 A plasma display is a e missive flat panel display where light is created by phosphors excited by  a plasma discharge between two flat panels of glass. Plasma displays are bright, with a wide color gamut. And can be produced in fairly large sizes, up to 150 cm diagonally. While very thin less than 10cm plasma displays use twice as much power as a comparable CRT television, and he high cost is prohibitive for most people.

Video Display Adapter

The video display adapter is also called the video card or graphics card. It is an expansion card that creates a circuit pathway so that data can travel from the main board to the monitor. The elements of the video display adapter which produce high quality p9icure are as follows:

1. Resolution: The resolution refers to the number of dots on the screen or pixels. Ti is expressed as a pair of numbers that give the number of dots on a line and the number of lines. The resolution is determined by the number of colors and the amount of video memory.
2. Color Depth: The color depth is the number of colors determined by the number of bits assigned to hold color value. Memory o the video adapter limits the number of colors that can be display at each resolution.
3. Refresh rate: The speed that the display uses to paint the dots o the screen.
4. Accelerator: Means the display can draw line and boxes and can move windows and scroll itself.

Monochrome

Monochrome monitors are very basic displays that produce only one color. The basic text mode in DOS is 80 characters across and 25 down. A company called Hercules graphics developed a video adapter that could do this for you.

CGA/EGA

The color graphics adapter introduced color to the personal computer. It can produce a resolution of 320x200 and has a palette of 16 colors but can only display 4 at a time. The IBM introduced enhanced graphics adapter, the proper monitor was capable of a resolution of 640x350 pixels and could display 16 colors from a palette of 64.

VGA

The VGA introduces three electron guns, one for each color, red, green and blue. This combination could produce 8 colors. By cutting the intensity of the beam in half, you could get 8 more colors for a total of 16. IBM developed an analog display system that could produce 64 different levels of intensity and capable of a resolution of 640x480 pixels and could display up to 256 colors.