Its will be discuss about all kinds of output devices of computer.

1. What is Output
 Data that has been processed into a useful form
 Output device is any hardware component that can convey
information to one or more people

2. Output Devices
Display Screens
Printers, plotters, multifunction, and microfilm / fiche devices
Audio-output devices
Video-output devices
Virtual-reality devices
Robots
Output Hardware

3. A CRT, for cathode-ray tube, is a vacuum tube used as a display
screen in a computer or video display terminal. Images are represented
on the screen by individual dots or “picture elements” called pixels. A
pixel is the smallest unit on the screen can be turned on and off or
made different shades.
Display Screen: CRT

4. Display Screen: CRT
What determines the quality of a CRT monitor?
 Screen resolution
 Text created with a smaller dot pitch is easier
to read
 Refresh rate is speed at which monitor redraws images on
screen

5. Resolution: The clarity or sharpness of a display screen is called
its resolution; the more pixels there are per square inch, the better
resolution. E.g., 640x480, 800x600, 1024x768, 1280x1024,
1600x1280.
Dot pitch : Dot pitch is the amount of space between the centers of
adjacent pixels, the closer the dots, the crisper the image. E.g., .
24mm, .27mm.
Refresh rate : Refresh rate is the number of times per second that
the pixels are recharged so that their glow remains bright. Typical
ranges from 50Hz to 150Hz.
Screen Clarity

6. Monochrome : Monochrome display screens display only two
colors --- usually black and white, amber and black, or green and
black.
Color : Color display screens can display between 16 and 16.7
million colors, depending on their type.
Monochrome Versus Color Screen

7. A video display adapter, also called a graphics adapter card, is a
circuit board that determines the resolution, number of colors,
and how fast images appear on the display screen.
– VGA: VGA, for Video Graphics Array, will support 16 to 256
colors, depending on resolution.
– SVGA: SVGA, for Super Video Graphics Array, will support
256 colors at higher resolution than VGA.
– XGA: XGA, for Extended Graphics Array, support up to 16.7
million colors at resolution of 1024*768 pixels.
Video Display Adapters

8. •Contains liquid crystals between 2 sheets of
material
•An electric current passes through the crystals
causing them to twist, block light waves and
create an image.
•Uses less than one third the power of a CRT
monitor
•Lightweight and compact (mobile users)
Gas Plasma Monitors
•A layer of gas instead of liquid crystals
LCD Monitors

9. Desktop Versus Portable Printers:
– Desktop printers
– Portable printers: transportable versus ultraportable
Impact Versus Nonimpact Printers:
– Impact Printers
• Dot-matrix
– Nonimpact Printers
• Laser printers
• Inkjet printer
• Thermal printer
Printer

10. An impact printer forms
characters or images by
striking a mechanism such as
a print hammer or wheel
against an inked ribbon.
The right is a Dot-matrix
printer
Impact Printers

11. Pins strike at the surface of the paper.
Advantages:
– Possible to obtain multiple copies by using carbon paper or
self carbonating paper.
Disadvantages:
– Slow
– Poor quality
– Noisy
– Not possible to print in colour.
Use:
– Receipts
Dot Matrix Printer

12. Inkjet printers spray small, electrically charged droplets of ink from four nozzles
through hotels in a matrix at high speed onto paper.
Inkjet Printers

13. Spray ink on to the paper
Advantages:
– Better quality and faster than dot matrix.
– Can be in colour.
Disadvantages:
– Cannot produce the two copies that a dot matrix can.
– Need to change the colour cartridges often.
– Cannot hold a lot of paper at one time.
– Less copies a minute than laser printers.
Uses:
– Applications which require portability and low volume output where changing
cartridges is not an issue. e.g. Small offices and stand alone systems.
– Applications which require very high quality output and where speed is not an
issue, e.g. Digital camera applications.
Ink jet printers

14. A laser printer uses the principle of dot-matrix printers in creating dot-like images.
However, these images are created on a drum, treated with a magnetically
charged ink-like toner (powder), and then transferred from drum to paper.
Laser Printers

15. Print in the same way as photocopiers.
Powdered ink, called 'Toner' is fused onto paper by heat
and pressure.
Advantage:
– Print more copies a minute than a ink jet printer.
– Ink lasts for longer so they don’t need to change the cartridges so
often.
Disadvantage:
– Expensive to purchase.
– Bulky and heavy.
Uses:
– Applications which require rapid, high quality and high volumes of
output, e.g. Most offices and schools.
Laser printers

16.  Color printer that produces photo-lab-
quality pictures
 Many photo printers have a built-in card
slot
 PictBridge is a standard technology that
allows you to print pictures directly from
a digital camera
Photo Printer

17.  Generates images by pushing electrically heated pins against
heat-sensitive paper
 Dye-sublimation printer, (also called a digital photo printer) uses
heat to transfer dye to specially coated paper
Thermal Printer

18.  Sophisticated printer used to produce high-quality drawings
 Large-format printer creates photo-realistic-quality
color prints
Plotter

19. Voice-output devices: Voice-output devices convert digital data
into speech-like sounds. Two types of voice-output technology:
– Speech coding uses actual human voices speaking words to provide
a digital database of words that can be output as voice sounds.
– Speech synthesis uses a set of 40 basic speech sounds (called
phonemes, the bases of all speech in English) to electronically create
any words.
Sound-output devices: Sound-output devices produce digitized
sounds, ranging from beeps and chirps to music.
Audio-output Devices

20.  Computer component that produces music, speech, or other
sounds
 Speakers, earphones, and earbuds are common devices
Audio Output Device

21. What is a Facsimile (fax) machine?
 Device that transmits and receives documents over telephone lines
What is a fax modem?
 Modem that allows you to send and receive electronic documents as
faxes
Fax

22. Data Projectors
Fax Machine
•Transmits and receives documents
over the telephone line
Multifunction devices
•Printer, scanner, copy machine and
fax machine all in one
Other Output Devices

23. Acronym for basic input/output system, the built-
in software that determines what a computer can
do without accessing programs from a disk. On
PCs, the BIOS contains all the code required to
control the keyboard, display screen, disk drives,
serial communications, and a number of
miscellaneous functions.
BIOS