Output Devices

The output unit is responsible for producing the
output in user readable form.
The function of an output device is to present
processed data to the user. The computer
sends output to the monitor if the user needs
to see the output. The output is send to the
printer whenever the output is needed in hard
copy form. The sound output is produced with
help of speaker. Graphic output is produced
with the help of plotter.
Output Devices

MONITOR

MONITORS
Monitor is the most common form of
output from computer. It displays
information in similar way to that shown
on television screen. The picture on a
monitor is made up of thousands of tiny
colored dots. called Pixels.

TYPES OF MONITORSCATHODE RAY TUBE

CATHODE RAY TUBE
The CRT works in the same way as
TV-it contains an electron gun at
back of the glass tube. This fires
electrons at groups of phosphor
dots, which coat the inside of the
screen. When the electron strike
phosphor dots they glow to give
color.

LIQUID CRYSTAL DISPLAY

LIQUID CRYSTAL DISPLAY
TFT is the device within each
pixel that sets the charge. And so
sometimes they are called “Liquid
Crystal Display” referring to the
material they use. TFT is a
variant of LCD technology. LCDs
use much less power than a normal
monitor.

Plasma MONITOR

Plasma MONITOR
Plasma Monitors are flat panel
display. The plasma technology
utilizes small cells containing
electrically charged ionized
gases across the face of a
plasma display, to collectively
form a visual image.

Touchscreen Monitor

Touchscreen Monitor
Touchscreen monitors are built by
combining touch sensitive
materials with a durable but
sensitive outer material that
protects the monitor from finger
but still allows monitor to detect
where a person is placing his
fingers. This technology is used in
Tablet PCs, checkout store
terminals and smartphones.

Organic light emitting display

Organic light emitting display
OLED is a light emitting display which has a
film of organic compounds which emits light
and responds to an electric current. This
organic layer of semi-conductors is situated
b/w 2 electrodes and atleast one of these
electrodes is transparent. The organic
molecules are electrically conductive as a
result of delocalisation of pi electrons
caused by conjugation over part or all the
molecule. These materials have
conductivity levels from insulators to
conductors hence k/a semi-conductors.

printers
A most convenient and useful
method by which computer can
deliver information is my means of
printed characters. Printers can be
divided into two categories:
 Impact Printers: There are
mechanical contact between the
print head and paper.
 Non-Impact Printers: There is
no mechanical contact between
the print head and paper.

Impact

Line
They print a line of text at a time, the full
width of the page, rather than using a
print head that moves back and forth.
The speed of the line printer is measured
by the number of line-per-minutes (lpm).
Typical main-frame line printers (IBM) use
a metal "band saw" character loop, and
solenoids for each character position,
typically 132 columns. The band spins at
several RPS and as each letter aligns with
the column it's intended to be, the
solenoid, or hammer behind that column
fires striking the letter through the ink
ribbon, onto the paper.

DrumIn a typical drum printer design, a fixed
font character set is engraved onto the
periphery of a number of print wheels, the
number matching the number of columns
(letters in a line) the printer could print.
The wheels, joined to form a large drum
(cylinder), spin at high speed and paper and
an inked ribbon is stepped (moved) past the
print position. As the desired character for
each column passes the print position, a
hammer strikes the paper from the rear and
presses the paper against the ribbon and the
drum, causing the desired character to be
recorded on the continuous paper. Because
the drum carrying the letterforms
(characters) remains in constant motion, the
strike-and-retreat action of the hammers
had to be very fast. Typically, they were
driven by voice coils mounted on the moving
part of the hammer.

Daisy WheelDaisy wheel printing is an impact printing
technology invented in 1969 by David S. Lee at
Diablo Data Systems. It uses interchangeable
pre-formed type elements to generate high-
quality output comparable to premium
typewriters but two to three times faster.
Daisy wheel printing was used in electronic
typewriters, word processors and computers
from 1972 The heart of the system is an
interchangeable metal or plastic "daisy wheel"
holding an entire character set as raised
characters moulded on each "petal". Different
typefaces and sizes can be used by replacing
the daisy wheel. It is possible to use multiple
fonts within a document: font changing is
facilitated by printer device drivers which can
position the carriage to the center of the
platen and prompt the user to change the
wheel before continuing printing.

Dot-matrixA type of printer that produces characters and
illustrations by striking pins against an ink ribbon to
print closely spaced dots in the appropriate shape.
Dot-matrix printers are relatively expensive and do
not produce high-quality output. However, they can
print to multi-page forms (that is, carbon copies),
something laser and ink-jet printers cannot do.
 · speed: Given in character per second (cps),the
speed can vary from about 50 to over 500 cps.
Most dot-matrix printers offer different speeds
depending on the quality of print desired.
 · print quality: Determined by the number of pins
(the mechanisms that print the dots), it can vary
from 9 to 24. The best dot-matrix printers (24
pins) can produce near letter-quality type,
although you can still see a difference if you look
closely.

Non- Impact

Electromagnetic
A magnetic of what is to be
printed can be written on a
drum surface. Then this
surface is passed through
magnetic powder which
adheres to charge areas. The
powder is passed onto paper.
Speeds of upto 250
characters per second are
obtained in such system.

Thermal
Thermal printer is a printer that
uses to transfer an impression
onto paper. It is a high quality
printer invented by “JACK
KIBLY”. And it is usually faster
than impact dot matrix printers.
They are also smaller, lighter
and consume less power, making
them ideal for portable.
 There are two types of
thermal printers:
 Direct thermal
 Thermal wax transfer

electrostatic
Electrostatic printing is a printing
technique done without any plate,
ink or type form. The paper is
coated with a thin layer of zinc
oxide, making it an insulator in the
dark and simultaneously a
conductor of electricity when
exposed to light.
These machines are used for
printing of geographic maps. With
the advancement in technology and
higher speed, the machines are also
being used to print small books.
Electrostatic printers are used for
short run printing as they are
faster and also do not cost much.

inkjet
Some printers direct a high-
velocity stream of ink towards
paper. This stream is
deflected, generally by
passing through an
electrostatic field such as
that used to deflect beams in
oscilloscopes. In some ink
stream is broken into droplets
by an ultrasonic transducer.

laser
Laser printing is an electrostatic digital
printing process. It very rapidly produces high-
quality text and graphics (and moderate-quality
photographs) by repeatedly passing a laser
beam back & forth over an electron-charged,
cylindrical drum, to define a differentially-
charged image. The drum then selectively collects
electrically-charged, powdered ink (i.e., toner),
and transfers the image to the loaded paper,
which is then heated in order to permanently fuse
the text/imagery. As with
digital photocopiers and multifunction/all-in-
one inkjet printers, laser printers employ
a xerographic printing process; but, laser printing
differs from analog photocopiers in that the
image is produced by the direct scanning of the
medium across the printer's photoreceptor. This
enables laser printing to copy images more quickly
than most photocopiers.

Multifunction
An MFP multifunctional is an office machine
which incorporates the functionality of
multiple devices in one, in addition to printing,
can scan, copy and, in many cases, send and
receive faxes. Some newer all-in-one printers
can connect directly to the web, so they can
print web pages, emailed documents or
documents stored in the cloud without being
hooked up to a computer.
Almost all printer manufacturers offer
multifunction printers. They are designed for
home, small business, enterprise and
commercial use. Naturally, the cost, usability,
robustness, throughput, output quality, etc. all
vary with the various use cases.[citation
needed] In the commercial/enterprise area,
most MFP have used laser-printer technology,
while the personal, SOHO environments,
utilize inkjet methods.

Speaker

Computer speakers, or multimedia speakers,
are speakers external to a computer, that
disable the lower fidelity built-in speaker. They
often have a low-power internal amplifier. The
standard audio connection is a 3.5 mm
(approximately 1/8 inch) stereo phone
connector often color-coded lime green
(following the PC 99 standard) for
computer sound cards. A few use aRCA
connector for input. There are
also USB speakers which are powered from the
5 volts at 500 milliamps provided by the USB
port, allowing about 2.5 watts of output power.
Computer speakers were introduced by Altec
Lansing in 1990.
Speaker

plotter

plotterThe plotter is a computer printer for
printing vector graphics. In the past,
plotters were used in applications such
as computer-aided design, though they
have generally been replaced with wide-
format conventional printers. A plotter
gives a hard copy of the output. It draws
pictures on paper using a pen. Plotters are
used to print designs of ships and
machines, plans for buildings and so on.

3d printer

3d printerThe process of 3D printing, which is
what created this likeness of the Star
Wars character Yoda, has gained in
popularity in recent years. There are
several types of 3D printers, but all
involve the same basic approach for
“printing” an object: transferring a
substance in multiple layers onto a
building surface, beginning with the
bottom layer.
A Dutch architect recently announced
plans to construct a house using 3D
printing, a technology that has been
around for decades but has only
entered the public consciousness in
the last few years.

A projector or image projector is an optical device
that projects an image (or moving images) onto a
surface, commonly a projection screen.
Most projectors create an image by shining a light
through a small transparent lens, but some newer types
of projectors can project the image directly, by using
lasers. A virtual retinal display, or retinal projector, is
a projector that projects an image directly on
the retina instead of using an external projection
screen.
Projector