Output Devices in Computer System

Output devices are a piece of computer hardware that takes data from a computer in machine-readable form and converts it into a human-understandable format. This may be in the form of audio, video, text, or hard copy, such as a written paper.

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Output Devices

The main difference between an input and an output device is that an input device sends data to the computer, while an output device collects data from the computer.

An example of using an output device is listening to a recorded podcast via a connected speaker. Auxiliary or peripheral systems have both output and input devices.

Different types of output devices are:

  • Monitor (LED, LCD, and CRT)
  • Printers (Dot-Matrix, Inkjet, and Laser)
  • Plotters
  • Projector
  • Speaker

Monitor

A monitor is a gadget that receives video signals from a computer and shows them on a monitor.

It is a soft copy output device that displays the result on screen like video, image, text, graphics, etc. Monitor is also referred to as VDU (Visual Display Unit) and VDT (Visual Display Terminal).

 monitor
Monitor

A display is made up of a panel, circuitry, a power supply, screen adjustment keys, and a casing that holds all of these components. A monitor is a device that displays data from a computer on a screen so that the user can communicate with it using a graphical interface.

Types of Monitor


1. CRT monitor

CRT-Monitor
CRT Monitor

A CRT monitor (cathode-ray tube) is an analog display system that produces a transparent image on the projector by focusing three electron beams over millions of phosphor dots to light them up.

The panel of a color display is made up of several stripes of overlapping red, green, and blue (RGB) phosphor dots, which are triggered by electrons and combine to create a wide range of colors.

The electron beam scans the entire front of the tube nearly 100 times per second to “paint” and refresh the image. The actual casings of computer monitors and televisions that use CRT technologies are big and bulky.

The long-distance between the front screen and the back of the case is needed to match the vacuum tube’s length.

Advantages of CRT monitor

  • Wider viewing angles.
  • Faster response times.
  • Cheaper and durable.
  • They give sharp and crisp images.
  • Its resolution is adjustable.

Disadvantages of CRT monitor

  • The screen may flicker causing eyestrain.
  • They are bulky and heavy.
  • They consume more electricity.
  • They may produce a lot of heat.

2. LCD Monitor

LCD-Monitor
LCD Monitor

Liquid crystal display (LCD) monitors are computer monitors or displays that use LCD technology to display clear images and are most commonly found in laptop computers and flat-panel monitors.

LCD monitor uses the light-modulating properties of liquid crystals combined with polarisers. The LCD monitor creates images with a special kind of liquid Crystal that is normally transparent but becomes opaque when charged with electricity.

The LCD screen are much thinner, soft and don’t flicker as compared to CRT.

LCD is now the clear leader over CRT in terms of color and picture quality, not to mention the ability to display large resolutions, thanks to the introduction of better LCD technology and its continuous improvement.

Advantages of LCD monitor

  • LCD is Portable i.e. easy to move from one to another place.
  • LCD does not require periodic refreshing
  • It consumes less electricity.
  • It emits zero (0) radiation thereby avoiding eye strain.
  • It required less space
  • LCD does not get affected by the magnetic fields.

Disadvantages of LCD monitor

  • It has a smaller viewing angle so the picture is best views when the person is in a straight position from the center of the monitor.
  • The liquid crystals do not emit light so the images are less sharp.
  • Resolution is normally fixed. i.e. non-adjustable.
  • It is relatively bright but not suitable for a very bright environment

3. LED monitor

LED-Monitor
LED Monitor

An LED monitor, also known as a light-emitting diode display, is a flat-screen computer with a shallow depth and is relatively light in weight.

The backlighting is the only difference between LED and a standard LCD monitor. LED screen works by emitting light in RGB (Red Green Blue) colors directly from the face of the display.

James P. Mitchell is widely credited as the inventor of the first LED display, which he created in 1977.

Advantages of LED monitor

  • A wider Viewing range is available.
  • Highly portable, thin & light-weight.
  • They use far less energy, as little as 20 watts.
  • The dynamic contrast ratio is higher.
  • Longer lifespan and less impact on the environment.

Disadvantages of LED monitor

  • LED monitors are more expensive.
  • LED monitors can shift color due to age and temperature.
  • The contrast ratio is not stable.
  • LED performance largely depends on the temperature of the operating environment.

Printer

printer
Printer

Printers are used for producing output on paper in a permanent readable form. A printer is an output device used to produce hard copy information. They produce the printed output of results, programs, and data(text or images).

Printers come in a variety of sizes, speeds, complexity, and price points. Higher-resolution color printing is usually done by more costly printers.

Types of Printers


1. Dot matrix Printer

Dot-matrix printers are those printers which can print the character and all kind of images by putting dots into paper. The dots are created by pins or wires, which are usually grouped in one or more vertical columns.

The shape of each character is formed in the form of tiny dots. The speed of the dot-matrix printer is measured in Character Per Second (cps).

The inked ribbon is placed between the print head and the paper. The more pins the printer have, there will be the better quality in printing.

dot-matrix-printer
Dot Matrix Printer

Advantages of Dot-Matrix Printer

  • Dot Matrix printers can print carbon copy
  • They are cheaper and easily available in the markets.
  • They use very little ink. Hence, the printing costs are lowest as compared to other printers.
  • The maintenance cost is low.

Disadvantage of Dot-Matrix Printer

  • The output of Dot Matrix is not of high resolution.
  • This printer is very noisy.
  • Limited color printing.
  • Very slow printing speed.

2. Inkjet Printers

Inkjet printers are a type of printer in which the printing is performed using inkjet technology. The technology works by spraying ionized ink onto the paper that is fed through the printer, which is guided by magnetic plates.

Inkjet printers are widely used as home and business printers because they are less expensive than other types of printers.

inkjet-printer
Inkjet Printer

A print head, ink cartridges, paper feed assembly, belt, and stabilizer bar make up an inkjet printer. Inkjet printers can produce high-resolution pictures with vibrant colors and high-quality photographs.

They are excellent image printers and are easy to get up and running. They’re able to print right away and don’t need any warm-up time.

Advantage of Ink-Jet Printer:

  • Easy to use.
  • Produce high-quality output.
  • Low in cost.
  • Faster than other printers.
  • Doesn’t produce noise while printing.

Disadvantage of Ink-Jet Printer:

  • Slower than other printers such as laser printers.
  • The print head is less durable.
  • Expensive replacement of ink cartridges.

3. Laser Printer

A laser printer is a type of printer that prints using a laser and electrical charge model rather than the conventional ink-on-paper method. With standard resolutions of 600 dots per inch or greater, laser printers have improved the neatness and complexity of print designs.

laser-printer
Laser Printer

A laser beam is fired on a mechanical cylinder known as a photoreceptor in a laser print process. As a result, a pattern appears on the photoreceptor, which is then sprayed with toner.

Toner sticks to the paper in shapes determined by the program used to print due to electrical charges. Finally, the toner is fused to the paper by heating the paper.

One of the most significant distinctions between laser printers and inkjet printers is that laser printers print using a powdered toner portion rather than liquid ink.

Today’s printers are highly advanced, often serving as copiers, fax machines, and scanners, but they can be expensive to maintain and operate regularly.

Advantage of Laser Printer

  • Printing Speed is very high 30ppm to 120 ppm. (#ppm = page per minute)
  • Color printing is possible.
  • Very high-quality printing output.
  • A low level of maintenance is required.
  • The ink used in a laser printer is inexpensive.

Disadvantage of Laser Printer

  • Laser printers are expensive machines.
  • It required periodic maintenance.
  • Laser printer also emits ultraviolent radiation that causes eye damage.
  • They produce noise & need warm-up time before printing.

Plotter

A plotter is a device that creates vector graphics drawings. The plotter uses a pen to draw lines on paper or any material like leather, that can be later cut down by knife.

Furthermore, a plotter printer can print on a wide range of materials other than paper. A plotter printer can print on plywood, aluminum, cardboard, or plastic, depending on your needs.

Plotter printers have a high resolution, making them suitable for documents that require high accuracy and reliability.

In the engineering and construction industries, Plotter printers are used widely.

Speaker

speaker
Speaker

A computer speaker is a sound-generating output hardware device that connects to a computer system via an audio jack or USB.

A cone, iron coil, a magnet, and housing make up a speaker (case). When a device sends electrical signals to the speaker, it causes it to move back and forth. This motion causes the outer cone to vibrate, causing sound waves to be picked up by our ears.

Projector

A projector, also known as an image projector, is a mechanism that uses light to project an image onto a large area, such as a white screen or a wall.

Most projectors work by shining a light through a tiny clear lens to produce an image, although some modern models use lasers to project the image directly.

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Projector

Projectors come in several shapes and sizes. They may be ceiling-mounted or free-standing and compact. Larger projectors, particularly those that project over a long distance, is usually installed on the ceiling (such as 30 feet or more).

These projectors can be used in libraries, meeting halls, auditoriums, and other public spaces.

Wherever there is a bright surface, portable projectors may be used (such as a white or light-colored wall). Most projectors have a variety of input options, including HDMI ports for newer equipment and VGA ports for older models. Some projectors also have Wi-Fi and Bluetooth capabilities.

Both Input-Output Devices

  • Modems
  • Network cards
  • Touch Screen
  • Headsets (Headset consists of Speakers and Microphone. Speaker act Output Device and     Microphone act as Input device)
  • Audio Cards / Sound Card
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by Janak Saud
Author of Informer Guru, IT Student

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