1. Output Devices
Here are a few of the crucial output devices found in computers:
Monitors,
Graphic plotters,
Printers.
Monitors
Monitors, also known as Visual Display Units (VDU), are a
computer's primary output device. Pixels, which are very small dots arranged
in a rectangular pattern, are used to create images. The amount of pixels
affects how crisp the image is.
2. For monitors, there are two different types of viewing screens.
• Flat-Panel Display.
• Cathode-Ray Tube.
Cathode-Ray Tube (CRT) Monitor
The CRT display is composed of tiny visual components known as
pixels. The image clarity or resolution increases with pixel size.
For example, the letter "e" in the word "help" is made up of many lighted
pixels.
A screen can only accommodate a certain number of characters at once.
A character box is a fixed spot on the screen where a standard character can
be positioned. The screen can be divided into a number of character boxes.
Most screens have a horizontal data display capacity of 80 characters and a
vertical data display capacity of 25 lines.
3. There are a few drawbacks to CRT.
• Large in Size
• High power consumption
4. Flat-Panel Display Monitor
A type of television devices known as flat-panel displays differ
from CRTs in terms of volume, weight, and power requirements. You can wear
them around your wrists or hang them from walls. Calculators, video games,
monitors, laptop computers, and graphical displays are some of the modern
uses for flat-panel displays.
Two categories of flat-panel displays are distinguished.
• Emissive display -Devices that turn electrical energy into light are called
emissive display. Examples include LED and plasma panels (Light-Emitting
Diodes).
• Non-Emissive Displays - These displays turn light from the sun or other
sources into graphic patterns using optical effects. LCD is one example
(Liquid-Crystal Device)
6. Printers
Printing information on paper is done using a printer, which is an output
device.
Two different kinds of printers exist.
• Impact Printers
• Non-Impact Printers
Impact Printers
Characters are printed on the paper by the impact printers by striking the
ribbon, which is then pressed against the paper.
Impact printers have the following characteristics.
• Very low consumable costs
• Very noisy
• Useful for bulk printing due to low cost
• There is physical contact with the paper to produce an image
7. These printers come in two varieties.
• Character printers
• Line printers
Character Printers
Printers that print one character at a time are known as character printers.
These are further divided into two types
• Dot Matrix Printer (DMP)
• Daisy Wheel
Dot Matrix Printer
Dot Matrix Printers are among the most widely used printers on the market.
These printers are well-liked due to how simple and inexpensive they are to
use. The head of the printer is made up of a matrix of pins with sizes of (5*7,
7*9, 9*7, or 9*9), and each character is printed as a pattern of dots; therefore,
the name "dot matrix printer."
9. Daisy Wheel
The Daisy Wheel Printer is so named because the head is perched on a
wheel and the pins that represent the characters resemble the petals of the
Daisy (flower). These printers are typically used for word processing in offices
that need to send out occasional, high-quality letters.
Advantages
• More reliable than DMP
• Better quality
• The fonts of character can be easily changed
Disadvantages
• Slower than DMP
• Noisy
• More expensive than DMP
10. Line Printers
Printers that print one line at a time are called line printers.
These are of two further categories.
• Drum Printer
• Chain Printer
11. Drum Printer
Drum printer is the name given to this printer because of its
shape. There are numerous tracks on the surface of the drum. Total tracks are
equivalent to paper size, so a drum with 132 tracks has a paper width of 132
characters. On the track is an embossed character set. There are three different
character sets on the market: a 48-character set, a 64-character set, and a 96-
character set. One line is printed each drum revolution. Drum printers print
300 to 2000 lines per minute, making them quick machines.
Advantages
• Very high speed
Disadvantages
• Very expensive
• Characters’ fonts cannot be changed
12. Chain Printer
This printer is known as a chain printer because it uses a chain of
character sets. 48, 64, or 96 characters make up a typical character set.
Advantages
• Character fonts can easily be changed.
• Different languages can be used with the same printer.
Disadvantages
• Noisy
13. Non-impact Printers
Characters are printed without the need of ribbon on non-impact
printers. Because they print an entire page at once, these printers are also
known as page printers.
These printers are of two types
• Laser Printers
• Inkjet Printers
Non-impact printer characteristics
• Faster than impact printers.
• They are not noisy.
• High quality.
• Support many fonts and different character size.
14. Laser Printers
These printers don't use impact technology. The dots required to
create the characters that will be printed on a page are created using laser
lights.
Advantages
• Very high speed
• Very high quality output
• Give good graphics quality
• Support many fonts and different character size
Disadvantages
• Expensive.
• Cannot be used to produce multiple copies of a document in a single
printing.
15. Inkjet Printers
Non-impact character printers that use inkjet technology are relatively
new. They use little drops of ink to print characters onto paper. The output
from inkjet printers is of a high calibre and has appealing features.
Due to the absence of hammering, they are quieter and offer a
variety of printing options. Printing in color is also an option. Multiple
copies of the same print job can be produced by some inkjet printer types.
Advantages
• High quality printing
• More reliable
Disadvantages
• Expensive as cost per page is high
• Slow as compared to laser printer
