output devices

M1-R5.1 & CCC · Chapter 1: Introduction to Computer · 6 min read

Output device

  • An Output device is an electromechanical device which accepts data from the computer and translates them into a form which is suitable for use by the user. 
  • The result of any processing done by the computer to the outside world performed by the output devices.

Types of output:

I. Hard copy output: A hard copy output is produced on a paper. Ex: Printed paper by printer.

II. Soft copy output: A soft copy output is not produced on a paper. It is in magnetic form that

can not be used directly.

Ex: Monitor screen result.

Type of output devices

Monitor

  • Monitor is the most popular output device used today for producing soft copy
  • output. 
  • It is also called  Visual display unit(VDU).
  • The picture on a monitor is made up of thousands of small coloured dots called pixels.
  • There are two basic types of monitor:
    • CRT(cathode ray tube): A CRT monitor is similar to a television. 
    • It contains an electron gun at the back which fires electrons at the group of phosphorous dots ,as a result phosphorous dots glow and give the colours.
    • There are two types of CRT’s:
      • Monochrom
      • Colour
    • TFT (Thin film transistor): It is also called flat panel. It is of two types 
      • LCD(Liquid crystal display)
      • LED(Light emitting diode)

Projector: 

  • It is used for projecting information from a computer to a large screen so that it can be simultaneously viewed by a large group of people .
  • It is widely used for giving presentations.

Voice response system

  • A voice response system enables a computer to talk to the user.
  • It produces audio output. Ex: Speaker

Speech synthesizer

  • It is an output device that converts textual data into spoken sentences.

Hard copy device:

Plotter

  • It is an output device used to produce precise graphics under computer control. 
  • Plotters are ideal output devices for architecture, engineers and city planners.

Printer

  • Printer is the most popular output device. Commonly used for producing hard copy output .
  • Printer are Broadly classified into two categories:



 

  1. Impact printer
  1. Non-Impact printer
  • Dot matrix printer
  • Chain/band printer
  • Drum printer
  • Daisy wheel printer
  • Laser printer
  • Inkjet printer
  • Thermal printer


 

impact printer:

  • An impact printer uses an electromechanical mechanism that causes hammers or pins to strike against a ribbon and paper to print the text.
  • Impact printers can produce multiple copies of the text.
  •  The disadvantage of impact type printers is that they are noisy, lower print quality and slower than  non-impact printers.

Types of impact printer:

a) Daisy wheel printer:

  • It is a character printer.
  • It is similar to a type writer.
  • It uses a metal or plastic disc containing each of the letters, numbers and other characters it supports.
  • Speed 10-75 CPS (character per second).

b) Dot matrix printer:

• It is a character printer which prints one character at a time.

• It prints characters and all kinds of images as a pattern of dots.

• Use a pin as a hammer to print the text.

• Speed 30-600 CPS(character per second).

c)Drum printer:

• It is a line printer which prints one line at a time.

• It uses a cylindrical drum as its printing mechanism.

• Speed 300-2000LPM (line per minute).

d)Chain/band printer:

• It is a line printer which prints one line at a time.

• It consist of metallic chain on which all the characters of the character set are

embossed.

• Speed 150-2500 LPM (line per minute).

Non-impact printer: 

  • Non-impact printers do not use any electromechanical mechanism to strike against ribbon and paper. 
  • They use thermal, chemical, laser beam and inkjet technology for printing the text. 
  • Usually a non-impact type printer is faster than an impact printer. 
  • The disadvantage of non-impact type printers is that they produce only a single copy of text at a time.

Type of non -impact printer:

a)Inkjet printer:

• It is a character printer.

• It uses inkjet technology to print text.

• It uses liquid ink.

• Speed 40-300 CPS(character per second )

b)Laser printer:

• It is a page printer which prints one page at a time.

• Use laser beam technology for printing text.

• Usually it uses dry ink powder called toner.

• Speed 4-200 PPM (page per minute).

c)Thermal printer:

• It uses thermal technology.

• It uses a special heat sensitive paper.

• Speed -250 mm/s whereas 1 mm=8 dots.