Output Devices - Type Of Output Devices

Output Devices

Following are few of the important output devices which are used in a computer.

  • Monitors
  • Graphic Plotter
  • Printer


Monitors, commonly called as Visual Display Unit (VDU), are the main output device of a computer.

It forms images from tiny dots, called pixels that are arranged in a rectangular form.

The sharpness of the image depends upon the number of pixels.

There are two kinds of viewing screen used for monitors.

  • Cathode-Ray Tube (CRT)
  • Flat- Panel Display

Cathode-Ray Tube (CRT) Monitor

Cathode-Ray Tube (CRT) Monitor

The CRT display is made up of small picture elements called pixels. The smaller the pixels, the better the image clarity, or resolution.

There are some disadvantages of CRT:

  • Large in Size
  • High power consumption

Flat-Panel Display Monitor

The flat-panel display refers to a class of video devices that have reduced volume, weight and power requirement in comparison to the CRT.

Emissive Displays - The emissive displays are devices that convert electrical energy into light. Example are plasma panel and LED(Light-Emitting Diodes).

Non-Emissive Displays - The Non-emissive displays use optical effects to convert sunlight or light from some other source into graphics patterns. Example is LCD(Liquid-Crystal Device)


Printer is an output device, which is used to print information on paper.

There are two types of printers:

  • Impact Printers
  • Non-Impact Printers

Impact Printers

Impact Printers

The impact printers print the characters by striking them on the ribbon which is then pressed on the paper.

Characteristics of Impact Printers are the following:

  • 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

Impact printers are of two types

  • Character printers
  • Line printers

Character Printers

Character printers are the printers which print one character at a time.

These are further divided into two types:

  • Dot Matrix Printer(DMP)
  • Daisy Wheel

1)Dot Matrix Printer

In the market one of the most popular printers is Dot Matrix Printer. These printers are popular because of their ease of printing and economical price. Each character printed is in form of pattern of dots and head consists of a Matrix of Pins of size (5*7, 7*9, 9*7 or 9*9) which come out to form a character that is why it is called Dot Matrix Printer.

Advantages of Dot Matrix Printer

  • Inexpensive
  • Widely Used
  • Other language characters can be printed

Disadvantages of Dot Matrix Printer

  • Slow Speed
  • Poor Quality

2)Daisy Wheel

Head is lying on a wheel and pins corresponding to characters are like petals of Daisy (flower name) that is why it is called Daisy Wheel Printer. These printers are generally used for word-processing in offices which require a few letters to be sent here and there with very nice quality.

Advantages of Daisy Wheel

  • More reliable than DMP
  • Better quality
  • The fonts of character can be easily changed

Disadvantages of Daisy Wheel

  • Slower than DMP
  • Noisy
  • More expensive than DMP

Line Printers

Line printers are the printers which print one line at a time.

Line Printer are of further two types

  • Drum Printer
  • Chain Printer

1)Drum Printer

This printer is like a drum in shape so it is called drum printer. The surface of drum is divided into number of tracks. Total tracks are equal to size of paper i.e. for a paper width of 132 characters, drum will have 132 tracks. A character set is embossed on track. The different character sets available in the market are 48 character set, 64 and 96 characters set. One rotation of drum prints one line. Drum printers are fast in speed and can print 300 to 2000 lines per minute.

Advantages of Drum Printer

  • Very high speed

Disadvantages of Drum Printer

  • Very expensive
  • Characters fonts cannot be changed

Chain Printer

In this printer, chain of character sets are used so it is called Chain Printer. A standard character set may have 48, 64, or 96 characters.

Advantages of Chain Printer

  • Character fonts can easily be changed.
  • Different languages can be used with the same printer.

Disadvantages of Chain Printer

  • Noisy

Non-impact Printers

Non-impact Printers

Non-impact printers print the characters without using ribbon. These printers print a complete page at a time so they are also called as Page Printers.

Non-Impact printers are of two types

  • Laser Printers
  • Inkjet Printers

Characteristics of Non-impact Printers

  • Faster than impact printers.
  • They are not noisy.
  • High quality.
  • Support many fonts and different character size.

Laser Printers

These are non-impact page printers. They use laser lights to produce the dots needed to form the characters to be printed on a page.

Advantages of Laser Printers

  • Very high speed
  • Very high quality output
  • Give good graphics quality
  • Support many fonts and different character size

Disadvantages of Laser Printers

  • Expensive.
  • Cannot be used to produce multiple copies of a document in a single printing.

Inkjet Printers

Inkjet printers are non-impact character printers based on a relatively new technology. They print characters by spraying small drops of ink onto paper. Inkjet printers produce high quality output with presentable features.

They make less noise because no hammering is done and these have many styles of printing modes available. Colour printing is also possible. Some models of Inkjet printers can produce multiple copies of printing also.

Advantages of Inkjet Printers

  • High quality printing
  • More reliable

Disadvantages of Inkjet Printers

  • Expensive as cost per page is high
  • Slow as compared to laser printer