Output device
Output device
An output is any piece of computer hardware equipment used to communicate the results of data processing carried out by an information processing to the outside world. Output may be viewed on a computer monitor, heard thought speakers, printed on printers, etc.
The output produced by the output devices can be of the following forms
Monitor
It is also known as visual display unit (VDU). The monitor is provided along with the computer to view the display result. A monitor is of two kinds; mono-chrome display monitor and colour display monitor.
A monochrome display monitor uses only one colour to display text and colour display monitor can display 256 colour at a time. An image on the monitor is created by the configuration of dots, also known as pixels. The clarity of image depends on three factors which are as follows
- Resolution of screen - Resolution refers to to the number of pixels in horizontal and vertical directions. the resolution of monitor is higher when the pixel are closer together.
- Dot pitch - It refers to the diagonal distance between two coloured pixels. The smaller the pics, the better the resolution.
Refresh Rate - it is the number by which per second. the higher the refresh rate the more solid the image looks on the screen.
The popular type of monitors are as follows
Cathode Ray Tube (CRT)
It is a typical rectangular shaped monitor that you see on a desktop computer. The CRT works in the same way as a television. It works by moving electron beam back and forth across the back of the screen. A screen covered with a find layer of phosphorescent elements, called phosphores.
Liquid Crystal Display (LCD)
These screens are used in laptops and notebooks sized PCS. A special type of liquid is sandwiched between two plates. It is a thin, flat a light weight screen made up of any number of colour or monochrome pixels arranged in front of a light source.
Liquid/Light Emitting Diode (LED)
It is an electronic device that emits light where electrical current is passed thought it. LED usually produces red light, but today's LEDs can produce RGB ( Red, Greeen and Blue) light, and white light as well.
3-D Monitor
It is a television that conveys depth perception to the viewers. 3D describes an image that provides the perception of length. When 3-D images are made interactive then user feels involved with the scene and this experience is called virtual reality.
Thin Film Transistor (TFT)
TFT and Active - matrix LCD (AMLCD) is a liquid Crystal Display (LCD). With active Matrix display each pixel is controlled by one of four transistors that can make the screen faster, brighter, more colourful than passive- matrix and capable of being viewed at different angles.
Because of this improved technology active Matrix screens after more expensive but better quality than a passive Matrix display.
Printers
A printer prints information and data from the computer onto a paper. It can print documents in colour as well as in black and white. The quality of a printer is determined by the clarity of a print. The speed of a printer is measured in character per second (CPS),line per minute (LPM) and pages per minute (PPM). Printer resolution is a numerical measure of print quality that is measured in dots per inch DPI.
Printers are divided into two basic categories
Impact printer
This type of printer strikes paper and ribbon together to form a character, like a typewriter. Impact printer can print a character or entire line at a time. They used pin or hammers that pressed an inked ribbon against the paper. They are less expensive, fast and make multiple copies with multipart paper.
There are four types of impact printer
(a) Dot Matrix printer
It forms characters using rows of pins which impact the ribbon on top of the paper therefore also called pin printers. Dot Matrix printers print one character at a time. It prints characters and images as a pattern of dots.
These printers are slow, noisy and are not commonly used for personal computers anymore. Many Dot Matrix printers are bi-directional, that is they can print the characters from either direction i.e. left or right.
(b) Daisy Wheel Printer
In Daisy wheel printers characters are fully formed on the petals like typewriter keys. Daisy wheel printers produce high resolution output and are more reliable than dot Matrix .
(c) Line printer
It is the high-speed printer capable of printing an entire line of text at once instead of one or more characters at a time. There are impact shaped character printers which print one line at a time. Print quality of line printer is not high.
(d) Drum Printer
An older line printer technology that uses formed character images around a cylindrical drum as its printing mechanism. When the desired character for the selected position rotated around the hammer line, the hammer hit the paper from behind and pused it into the ribbon and onto the character.
Non- Impact Printer
This type of printer uses electrostatic chemicals and inkjet technologies. They do not hit or impact a ribbon to print. It can produce high quality graphics and often a wide variety of fonts than impact printers.
There are following types of non- impact printers
- Inkjet printer - It is a printed that places extremely a small droplets of ink onto paper to create an image. It sprays ink onto paper to form characters and prints high quality text and graphics.
- Thermal printer - It uses heat on chemically treated paper to form characters. Fax machines that used rolls of paper are also of thermal printers type. It is relatively slow, expensive and requires special paper.
3. Laser printer- It provides the highest quality text and images for personal computer. They can print in different fonts that is, type style and sizes.
Laser printer uses laser beam on two photo send sensitive surface for printing. It prints high quality graphics and more expensive than impact printers.
4. Electromagnetic printer -Electrographic or electro- photographic printers are very fast printers and they fall under the category of page printer.
5. Electrostatic Printer- these printers are generally used for large format printing. They are favoured by large printing shops because of their ability to print fast and making low cost.
Plotter
It is an output device that uses a pen, pencil, marker or other writing tools for making vector graphics.
A plotter is a special kind of output channel like a printer that produces images on paper. They are mainly used to produce large drawings or images such as construction plans, blueprints for mechanical objects AUTOCAD, CAD/CAM, etc.
Plotters usually come in two designs as follows
- Flat Bed plotter
2.Drum plotter
Speaker
It is an output device that receives sound in the form of electric current. It needs a sound card connected to a CPU that generates sound via a card.
These are used for listening music for being audible in seminar during presentations, etc. Computer speakers are the speakers which are attached internally or externally to a computer system.
Headphones
These are a a pair of small loudspeakers or less commonly a single speaker held close to a users ears and connected to a single source such as an audio amplifier, radio, CD player aur portable media player. They are also known as stereo phones headsets or cans.
Projector
It is is an output device which is used to project information from a computer onto a large screen, so it can be viewed by a large group of people simultaneously. Projectors are widely used for classroom training for conference halls with the large audience. It provides a temporary output display.
Input/Output Port
The peripheral devices can be connected to a computer in several ways. Input /output ports are the external interfaces that are used to connect input and output devices like printer monitor and joystick to computer.
The output produced by the output devices can be of the following forms
Monitor
It is also known as visual display unit (VDU). The monitor is provided along with the computer to view the display result. A monitor is of two kinds; mono-chrome display monitor and colour display monitor.
A monochrome display monitor uses only one colour to display text and colour display monitor can display 256 colour at a time. An image on the monitor is created by the configuration of dots, also known as pixels. The clarity of image depends on three factors which are as follows
- Resolution of screen - Resolution refers to to the number of pixels in horizontal and vertical directions. the resolution of monitor is higher when the pixel are closer together.
- Dot pitch - It refers to the diagonal distance between two coloured pixels. The smaller the pics, the better the resolution.
The popular type of monitors are as follows
Cathode Ray Tube (CRT)
It is a typical rectangular shaped monitor that you see on a desktop computer. The CRT works in the same way as a television. It works by moving electron beam back and forth across the back of the screen. A screen covered with a find layer of phosphorescent elements, called phosphores.
Liquid Crystal Display (LCD)
These screens are used in laptops and notebooks sized PCS. A special type of liquid is sandwiched between two plates. It is a thin, flat a light weight screen made up of any number of colour or monochrome pixels arranged in front of a light source.
Liquid/Light Emitting Diode (LED)
It is an electronic device that emits light where electrical current is passed thought it. LED usually produces red light, but today's LEDs can produce RGB ( Red, Greeen and Blue) light, and white light as well.
3-D Monitor
It is a television that conveys depth perception to the viewers. 3D describes an image that provides the perception of length. When 3-D images are made interactive then user feels involved with the scene and this experience is called virtual reality.
Thin Film Transistor (TFT)
TFT and Active - matrix LCD (AMLCD) is a liquid Crystal Display (LCD). With active Matrix display each pixel is controlled by one of four transistors that can make the screen faster, brighter, more colourful than passive- matrix and capable of being viewed at different angles.
Because of this improved technology active Matrix screens after more expensive but better quality than a passive Matrix display.
Printers
A printer prints information and data from the computer onto a paper. It can print documents in colour as well as in black and white. The quality of a printer is determined by the clarity of a print. The speed of a printer is measured in character per second (CPS),line per minute (LPM) and pages per minute (PPM). Printer resolution is a numerical measure of print quality that is measured in dots per inch DPI.
Printers are divided into two basic categories
Impact printer
This type of printer strikes paper and ribbon together to form a character, like a typewriter. Impact printer can print a character or entire line at a time. They used pin or hammers that pressed an inked ribbon against the paper. They are less expensive, fast and make multiple copies with multipart paper.
There are four types of impact printer
(a) Dot Matrix printer
It forms characters using rows of pins which impact the ribbon on top of the paper therefore also called pin printers. Dot Matrix printers print one character at a time. It prints characters and images as a pattern of dots.
These printers are slow, noisy and are not commonly used for personal computers anymore. Many Dot Matrix printers are bi-directional, that is they can print the characters from either direction i.e. left or right.
(b) Daisy Wheel Printer
In Daisy wheel printers characters are fully formed on the petals like typewriter keys. Daisy wheel printers produce high resolution output and are more reliable than dot Matrix .
(c) Line printer
It is the high-speed printer capable of printing an entire line of text at once instead of one or more characters at a time. There are impact shaped character printers which print one line at a time. Print quality of line printer is not high.
(d) Drum Printer
An older line printer technology that uses formed character images around a cylindrical drum as its printing mechanism. When the desired character for the selected position rotated around the hammer line, the hammer hit the paper from behind and pused it into the ribbon and onto the character.
Non- Impact Printer
This type of printer uses electrostatic chemicals and inkjet technologies. They do not hit or impact a ribbon to print. It can produce high quality graphics and often a wide variety of fonts than impact printers.
There are following types of non- impact printers
- Inkjet printer - It is a printed that places extremely a small droplets of ink onto paper to create an image. It sprays ink onto paper to form characters and prints high quality text and graphics.
- Thermal printer - It uses heat on chemically treated paper to form characters. Fax machines that used rolls of paper are also of thermal printers type. It is relatively slow, expensive and requires special paper.
3. Laser printer- It provides the highest quality text and images for personal computer. They can print in different fonts that is, type style and sizes.
Laser printer uses laser beam on two photo send sensitive surface for printing. It prints high quality graphics and more expensive than impact printers.
4. Electromagnetic printer -Electrographic or electro- photographic printers are very fast printers and they fall under the category of page printer.
5. Electrostatic Printer- these printers are generally used for large format printing. They are favoured by large printing shops because of their ability to print fast and making low cost.
Plotter
It is an output device that uses a pen, pencil, marker or other writing tools for making vector graphics.
A plotter is a special kind of output channel like a printer that produces images on paper. They are mainly used to produce large drawings or images such as construction plans, blueprints for mechanical objects AUTOCAD, CAD/CAM, etc.
Plotters usually come in two designs as follows
- Flat Bed plotter
Speaker
It is an output device that receives sound in the form of electric current. It needs a sound card connected to a CPU that generates sound via a card.
These are used for listening music for being audible in seminar during presentations, etc. Computer speakers are the speakers which are attached internally or externally to a computer system.
Headphones
These are a a pair of small loudspeakers or less commonly a single speaker held close to a users ears and connected to a single source such as an audio amplifier, radio, CD player aur portable media player. They are also known as stereo phones headsets or cans.
Projector
It is is an output device which is used to project information from a computer onto a large screen, so it can be viewed by a large group of people simultaneously. Projectors are widely used for classroom training for conference halls with the large audience. It provides a temporary output display.
Input/Output Port
The peripheral devices can be connected to a computer in several ways. Input /output ports are the external interfaces that are used to connect input and output devices like printer monitor and joystick to computer.
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