OUTPUT DEVICES

WHAT IS OUTPUT DEVICE.
 The output devices are the devices which are used to display the result
generated by the computer system.
 Monitor, printer, plotter, speaker are the example of output devices.
FUNCTIONS OF INPUT DEVICES:
Accept the result from the CPU.
Convert that result into human readable form.
Supply this result to output device.

EXPLAIN THE VISUAL DISPLAY UNIT

EXPLAIN CRT (CATHOD RAY TUBE) MONITER

 The monitor is the common output device mostly used It is a softcopy output
device.
 It can be thought of as a high resolution TV set.
 The monitor can also determine if the display will be colour, black and white, or
include graphical objects (pictures).
 Two types of monitors are used.
     CRT monitors.
     Non CRT monitors.
 Most computer monitors are based on Cathode Ray Tube (CRT) technology.
 The basic operation of these tubes is similar to that in television sets.

EXPLAIN THE NON CRT DISPLAY.

LCD (Liquid Crystal Display)

 In LCD, a liquid crystalline material is sandwiched between two glass or a plastic
plates.26
 The front plate is transparent and the back plate is reflective.
 There is a coating of thin film on the front plate.
 The coating is transparent and conductive. Its sections (segments) are in the
shape of desired characters.
 LCDs do not emit their own light. Therefore, a light source is to be used.
 LCDs simply change the reflection of available light. Today, most LCDs used are
of the type that produces dark images on a silver background.

PDP (Plasma Displays Panel)
 In Plasma Displays, ionized gas is sandwiched between two glass plates.
 A number of parallel wires run horizontally as well as vertically.
 A small amount of current is passed through one horizontal and one vertical wire
to cause the gas to glow at a spot at the intersection of the wires.
 The IBM 581 display employs 960 horizontal and 768 vertical pixel as compared
to IBM-PC colour graphic adapter which is provided with 320 X 200 pixels in
medium resolution and 640 X 200 in high resolution.

WHAT IS PRINTER? EXPLAIN THE TYPES OF PRINTER.

 The printer is a most commonly used output device.
 It is used to producing the hard copy output.
 It prints characters, symbols & graphics on the paper.
 Printer can be categorised according to the technology used in printer, speed,
and approach of printing, colours, language & the quality of printing.
 Mainly printer can be classified in two types:
o Impact printer
o Non impact printer

IMPACT PRINTER:

 It works on the same mechanism of type-writer.
 It forms a character or image by striking mechanism such as hammer or wheel
against to ink ribbon, leaving an image on paper.
 It is oldest technology and still is in used.
 It can capable to print single character or line at the same time.
 Commonly types of impact printers are dot matrix, daisy wheel, chain, drum
printer.

NON IMPACT PRINTER

 Non impact printer forms characters & images on paper without actually striking
the paper.
 Paper & print head come in contact & hence the text or image is formed.
 Ink jet & laser printer are example of non impact printer.

EXPLAIN IMPACT PRINTERS.

Dot matrix printer:
 Character printer.
 Capable to print single character at the same time.
 Forms characters & images as a pattern of dots.
 Contains a print head which moves horizontally across paper.
 Uses 5 × 7 matrix to form a character.
 Print by hammering the pins on inked ribbon to leave ink impressions on the
paper.
 Able to print 30 to 600 characters per second.

DAISY WHEEL PRINTER:
 Character printer.
 Able to print a single character at the same time.
 Contain a metal wheel on which the characters & numbers are raised on the each
petal.
 The wheel is rotated very fast when the desired characters arrives at correct
position a print hammer strike to produce output.
 Different type of font face can be used by replacing the daisy wheel.
 Able to print bold letter by striking on specific characters twice or thrice.29
Prepared By: Meghna Bhatt
 Capable to print 10 to 50 characters per second.

DRUM PRINTER:
 It’s a line printer.
 Able to print a line at the same time.
 Consist of a solid cylindrical drum with characters embossed on it in circular
band.
 Each band consists of character set which contains 96 characters.
 Drum rotates fastly when desired characters arrives an appropriate hammer
stike on ribbon & character is print on paper.
 Capable to print 300 to 2000 lines per minute.

CHANIN PRINTER:
 It’s a line printer.30
Prepared By: Meghna Bhatt
 Able to print a line at the same time.
 Consist of a metallic chain on which all characters of character set are embossed.
 Character set contains 48, 64 or 96 characters.
 Characters are embossed several times.
 Chain rotates at high speed when the desired characters in correct position the
hammer strikes & the characters are print on paper.
 Capable to print 400 to 2500 lines per minutes.

EXPALAIN NON-IMPACT PRINTERS.

INK-JET PRINTER:
 It’s non-impact printer.
 It’s a character printer.
 Forms characters and all kinds of images by spraying drops of ink on to the
paper.
 Print head contains 64 tiny nozzles.
 To print a character the printer the printer selectively heats the appropriate set
of nozzle as the print head moves horizontally.
 Inkjet printer can either colour or monochrome.
 Capable to print 30 to 400 characters per minutes.

LASER PRINTER:
 It’s non-impact printer.
 It’s a page printer.
 Three main components laser beam, a multi-sided mirror, a photoconductive
drum & toner.
 To print page laser beam is focused on drum by spinning multisided mirror.
 Drum is electric charged.
 Toner which is composed of oppositely charged ink particles, stick to the drum.
 Then toner focused on the paper with heat & pressure to generate output.
 Low speed laser printer can print 4 to 12 page per minute while high speed laser
printer Capable to print 500 to 1000 pages per minutes.

WHAT IS PLOTTER? EXPLAIN ITS TYPE

 Plotter is an output device which is capable to producing hardcopy output of
graphics.
 Used to producing wide format printing.
 It is an ideal output device for architects, engineers, city planners and other who
need to generate hardcopy output of widely varying in sizes.
 Woks on the same mechanism of human holding pen & moving on paper.
 Contains multiple pens & pencil which can be easily changed out in order to
create drawing of different colours.
 Normally generate output very slowly.
 Mainly two types of plotters are used:
o Drum plotter
o Flatbed

Drum plotter:
 In the case design has to be made is placed over a drum.
 It consist one or more than penholders which are mounted to the drum surface.
 The drum plotter both the paper and the pen move.
 The paper is contained on two rollers and passes over a drum.
 The pen is driven along fixed arm set across the length of the drum.
 It is especially useful for plotting continuous line graph.
 The accuracy of the drum type depends on the paper transport mechanism,
which in turn is dependent on the width of the paper and it can also produce larger drawings.

Flatbed Plotter
 The Flatbed Plotter is generally more expensive and can produce very detailed and accurate drawings.
 The paper is mounted on a stationary flatbed.33
 The pen is mounted on a moveable arm.
 Colour drawing can be produced by some plotters through interchangeable
pens.
 Able to draw output in small size as A4 size or can able to generate very large
size can be up to 20ft by 50ft.
 Specially used in the design of cars, ships, aircrafts, buildings, highways etc.

WRITE A BRIEF NOTE ON SPEAKER.
 The speaker is output device which is connected to computer’s soundcard.
 The speaker output the sound generated by the sound card.
 Audio data is generated by computer is send to audio card which is located
inside extension slot.
 It can translate data into audio signal which are sending to speaker.
 The speaker can able to produced series of different tones.