Output Devices in Computer System

Output Devices:-

The Output device displays the result of the processing of raw data that is entered in the computer through an input device. There are a number of output devices that display output in different ways such as text, images, hard copies, and audio or video.
The key distinction between an input device and an output device is that an input device sends data to the computer, whereas an output device receives data from the computer.

There are 10 most popular output devices available in market

1. Monitor
2. Printer
3. Headphones
4. Computer Speakers
5. Projector
6. GPS
7. Sound Card
8. Video Card
9. Braille Reader
10. Speech-Generating Device

1. Monitor

Mode: Visual

Function: A monitor consists of a screen, circuitry, a power supply, buttons to adjust screen settings, and a casing that contains all of these components. A monitor displays data from a computer onto a screen so the user can interact with the data via a digital interface.

Popular Brands: Acer, Alienware, Apple, Asus, Dell, HP, LG, Lenovo, Samsung

Origin Story: The first monitors used the same technology as early televisions, relying on a cathode ray tube and a fluorescent screen. This technology was first utilized for computer monitors in 1965 in the Uniscope 300 machine, which had a built-in CRT display. CRT display lights up a series of dots with a beam on an active part of the screen. This resulted in a maximum resolution of 1600 by 1200 pixels. LCD (liquid crystal display) entered the market in 2000 and outsold CRT monitors in 2007. Nowadays, monitors incorporate flat display technology. Plasma monitors are brighter than both CRT and LCD and function by illuminating tiny charged gas bubbles, or plasma, in the screen.

Note: VDT (video display terminal) and VDU (video display unit) are alternative names for monitors.

The types of monitors are given below.

i) CRT (cathode ray tube) monitors

It is the pioneering technology used in the first monitors, which you will easily recognize since they were the ones that transmitted the image in black and white.

Its acronyms mean Cathode Ray Tubes, which use electrons to transmit the image they manage to capture by means of an antenna, as you will see these are the first designs that were used by the industry, among its features highlight the heavy components as well as the robust proportions.

However, the era of black and white lasted little, as the companies decided to incorporate the colors for a better appreciation of the image, all this, through the implementation of tubes fused in phosphorus and a cannon, through which, I passed the image and projected it in colors a little more chromatic than the simple black and white.

ii) LCD (liquid crystal display) Monitors

Whose most popular name is LCD for its acronym that means Liquid Crystal Display. Its structure is thin and works through a series of monochrome pixels that take shape through a light.

The minimum resolution of this type of monitor has a definition that goes from 1280 x 720 pixels to 3840 x 2160 pixels. The response time of the image is the same as that which takes a pixel to change color and is one of the most available options in the market.

Although LCD monitors were initially created for the television industry, their technology is present in a large number of household appliances, where it is very useful, to mention an example, calculators use LCD screens.

Features

• These are lightweight so they can be hung on the wall
• They can be hung on the wall generating clear and colorful images
• Their sizes are moderate these monitors tend to occupy very little space, are accommodating and combinable with any space in the home or office where they will be installed

And the best feature of these monitors is that given their components, they do not require a higher energy consumption, so their use will help you reduce certain amounts of the electric service bill.

Classification of LCD Panel

• TN (Twisted Nematic): is a type found in the cheapest LCD monitors. In that type, liquid crystal molecules work at 90º angles. Monitors that use TN can have a poor image display in very fast animations.
• STN (Super Twisted Nematic): is an evolution of the TN standard, able to work with images that change state quickly. Besides that, its molecules have improved movements, making the user get to see the image of the monitor satisfactorily at angles many times higher than 160º.
• GH (Guest Host): GH is a kind of pigment contained in the liquid crystal that absorbs light. This process occurs according to the level of the applied electric field. With this, it is possible to work with several colors. 

iii) TFT Monitor(Thin Film Transistor )

It is a variant of LCD televisions, based on the size of the screen, this technology allows the implementation of other components, that the larger the screen, the image can be transmitted clearly and not in a pixelated way, which is the result that is obtained when the screen does not have the adequate resolution to project to that one.

This technology is based on the application of transistors for each of the pixels of the screen, which allows a greater magnification and illumination of the image; It is an invention that combines liquid crystal with high resolution.

iv) LED (light-emitting diodes) Monitors

This type of screen is composed of light-emitting diodes or LEDs. Its name comes from the English Light Emitting Diode, which is understood as a light-emitting diode.

These panels or monochromatic or polychromatic LED modules that allow viewing data and images for the user of a PC are made in turn with RGB LEDs that are forming the pixels of the screen. The minimum resolution of these monitors is 1024×768.

Features

• Capable of projecting the image with great dynamism and resolution
• Display a very colorful and vivid sample of the image, in such a way that realism is appreciated in what the screen projects
• The transmission of a high-resolution image can be perceived at long distances.

Comparison between LCD and LED (LCD x LED)

Resolution 1920 × 1080	LCD Monitor	Led Monitor
Contrast Ratio	12,000,000: 1	100,000,000: 1
Brightness	250 cd / m²	250 cd / m²
Weight	2.4 kg	2.4 kg
Energy Star Certified	No	Yes

The following video shows the actual difference from an LCD monitor to an LED. The left one is an LED monitor (22MP55HQ-P), while the one on the right is an LCD monitor (L222WS). The first example is watching a movie, the second in a game.LCD monitors are 40% more efficient than older CRT monitors, while LED monitors offer 20% energy efficiency compared to LCD monitors, which qualifies them with Energy Star certified.

The LCD and LED monitors have specs on some equal points, and on other divergent ones. These points can be measured. If you are just an ordinary computer user with no advanced imaging needs, you probably do not realize the difference between the two. However, as we have seen in the comparative table and in the video, they do have their differences.

One thing is for sure: if you have a CRT monitor tube (we know, it’s quite difficult but still exists) clumsy on your desk these days, upgrade to an LCD or LED monitor, as they both offer thinner, lighter profiles and energy efficient because what you spend to acquire one of these two types of monitors, you end up saving on the energy bill.

v) DLP Monitor

It is a monitor that has possibly the highest definition at present. It works based on the principles of digital micromirror devices or DMD. In this type of screens, the light is digitally modulated by millions of micromirrors.

These tiny structures coordinate to send this light into the space of a pixel. In this way, they can produce 1024 gray scales. It is an ideal screen for those who prefer to play video games or concentrate on the image or video editing.

vi) Touchscreens Monitor

This type of monitor works in the same way as digital smartphones and tablets, so popular. Simply touch the screen to activate a menu or execute a specific function.

Its structure is sensitive enough to enable dragging options on its surface, which facilitates the use of graphics and design programs. Partial devices are also available that are coupled to LCD monitors or LEDs, to turn them into tactile.

Currently, there are touchscreens that can be installed on a normal screen, of any type (LCD, monitors and televisions CRT, plasma, etc.). Touchscreens became popular for use in industry devices, public computers (such as museum exhibits, information screens, bank ATMs, etc.) where keyboards and mice do not allow for a successful, intuitive, fast interaction, or exact of the user.

There are ATMs (touch screen ATMs), through which the user can enter information about their bank account, choose the type of transaction they wish to make, etc. It is also possible to find touch screens in museums (designed to present information interactively).

vii) Plasma Screen Monitor

They owe their name to the use of cameras or fluorescent sheets inside, which makes it possible to enjoy a large image and excellent color. Obviously, we are facing teams of large proportions, which occupy a large space, being appropriate to adapt to the walls to keep them well supported.

Its main characteristic lies in the balance it achieves between the brightness and contrast of the image, the greater or better the balance, the sharper the image and the resolution of it.

viii) OLED Monitors

This type of screens, still not very common in the market, is the most extreme monitor model in this matter. It works by means of an organic light-emitting diode. From there comes its acronym that forms the term OLED ( organic light-emitting diode).

Within its thin structure, an electro-luminescent layer, created from organic components, works with a light that is generated inside. This is how images from the computer are formed. The funny thing is that when turned off these screens become transparent, and can even be curved.

It can offer images in 360 or 3D vision.

2. Printer

Mode: Print

Function:  Printers take electronic data sent from a computer and produces hard copies of the processed data. It enables the user, to print images, text or any other information onto the paper. The function of a printer is to create a copy of whatever is sent from the computer to the printer.

Popular Brands: Brother, Canon, Epson

Origin Story: Photocopying, also known as xerography, is the origin-technology of modern-day printing and was invented in 1938 by Chester S. Carlson of Queens, New York. The first inkjet printer was developed in 1951. There are many different types of printers, with inkjet and laser printers being two of the most common. Modern printers usually connect to a computer with a USB cable or via Wi-Fi.

Note: A plotter, which is also a type of print output device, is a similar type of hardware device to a printer. Unlike a printer, however, plotters use writing tools, such as pen, pencil, marker, to draw lines. Designed to use vector graphics, plotters were once commonly employed for computer-aided design, but have now been largely replaced by wide-format printers.

Based on the printing mechanism:-

The printers are of two types: 

i)Impact Printers 

ii) Non-impact Printers.

types of printer

Impact Printer

The impact printer uses a hammer or print head to print the character or images onto the paper. The hammer or print head strikes or presses an ink ribbon against the paper to print characters and images.

Impact printers are further divided into two types.

A. Character Printers

B. Line printers

A) Character Printers

Character printer prints a single character at a time or with a single stroke of the print head or hammer. It does not print one line at a time. Dot Matrix printer and Daisy Wheel printer are character printers. Today, these printers are not in much use due to their low speed and because only the text can be printed. The character printers are of two types, which are as follows:

i) Dot Matrix Printer

Dot Matrix Printer is an impact printer. The characters and images printed by it are the patterns of dots. These patterns are produced by striking the ink soaked ribbon against the paper with a print head. The print head contains pins that produce a pattern of dots on the paper to form the individual characters. The print head of a 24 pin dot matrix contains more pins than a 9 pin dot matrix printer, so it produces more dots which results in better printing of characters. To produce color output, the black ribbon can be changed with color stripes. The speed of Dot Matrix printers is around 200-500 characters per second.

ii) Daisy Wheel Printer

Daisy Wheel Printer was invented by David S. Lee at Diablo Data Systems.It consists of a wheel or disk that has spokes or extensions and looks like a daisy, so it is named Daisy Wheel printer. At the end of extensions, molded metal characters are mounted. To print a character the printer rotates the wheel, and when the desired character is on the print location the hammer hits disk and the extension hits the ink ribbon against the paper to create the impression. It cannot be used to print graphics and is often noisy and slow, i.e., the speed is very low around 25-50 characters per second. Due to these drawbacks,these printers have become obsolete.

B) Line Printers:

Line printer, which is also as a bar printer, prints one line at a time. It is a high-speed impact printer as it can print 500 to 3000 lines per minute. Drum printer and chain printer are examples of line printers.

i) Drum Printer:

Drum printer is a line printer that is made of a rotating drum to print characters. The drum has circular bands of characters on its surface. It has a separate hammer for each band of characters. When you print, the drum rotates, and when the desired character comes under the hammer, the hammer strikes the ink ribbon against the paper to print characters. The drum rotates at a very high speed and characters are printed by activating the appropriate hammers. Although all the characters are not printed at a time, they are printed at a very high speed. Furthermore, it can print only a predefined style as it has a specific set of characters. These printers are known to be very noisy due to the use of hammering techniques.

ii) Chain Printer:

Chain printer is a line printer that uses a rotating chain to print characters. The characters are embossed on the surface of the chain. The chain rotates horizontally around a set of hammers, for each print location one hammer is provided, i.e., the total number of hammers is equal to the total number of print positions.

The chain rotates at a very high speed and when the desired character comes at the print location, the corresponding hammer strikes the page against the ribbon and character on the chain.They can type 500 to 3000 lines per minute. They are also noisy due to the hammering action.

Non-Impact Printer:

Non-impact printers don't print characters or images by striking a print head or hammer on the ink ribbon placed against the paper. They print characters and images without direct physical contact between the paper and the printing machinery. These printers can print a complete page at a time, so they are also known as page printers. The common types of non-impact printers are Laser printer and Inkjet printer:

i) Laser Printer:

A laser printer is a non-impact printer that uses a laser beam to print the characters. The laser beam hits the drum, which is a photoreceptor and draws the image on the drum by altering electrical charges on the drum. The drum then rolls in toner, and the charged image on the drum picks the toner. The toner is then printed on the paper using heat and pressure. Once the document is printed, the drum loses the electric charge,and the remaining toner is collected. The laser printers use powdered toner for printing instead of liquid ink and produce quality print objects with a resolution of 600 dots per inch (dpi) or more.

ii) Inkjet Printer:

The inkjet printer is a non-impact printer that prints images and characters by spraying fine,ionized drops of ink. The print head has tiny nozzles to spray the ink. The printer head moves back and forth and sprays ionized drops of ink on the paper, which is fed through the printer. These drops pass through an electric field that guides the ink onto the paper to print correct images and characters.

An inkjet printer has cartridges that contain ink. Modern inkjet printers are color printers that have four cartridges containing different colors: Cyan, Magenta, Yellow, and Black. It is capable of printing high-quality images with different colors. It can produce print objects with a resolution of at least 300 dots per inch (dpi).

3. Headphones

Mode: Sound

Function: Headphones output audio from a computer through two individual headphones for a single listener. Also known as earphones, headphones allow you to listen to audio without disrupting other people in the vicinity.

Popular Brands: Sennheiser, JBL, Bose, Sony, Skullcandy

Origin Story: There’s no single figure who invented headphones, but the use of headphones stems from the military. Nathaniel Baldwin of Utah submitted a headphone prototype to the U.S. Navy in 1910, which was adopted some years after by Naval radio operators. Koss Corporation then created the first commercial stereo headphones in 1958. Nowadays, headphones come in all shapes and sizes, from basic earbuds to the traditional style with padding around the earpieces and a connecting band that fits over the user's head.

Note:- Headphones were popularized for mainstream use in 1979 by Sony Walkman.

4. Computer Speakers

Mode: Sound

Function: Computer speakers are hardware devices that transform the signal from the computer's sound card into audio. Speakers create sound using internal amplifiers that vibrate at different frequencies according to data from the computer. This produces sound.

Popular Brands: Audioengine, Logitech, Razer, Harman

Origin Story: Speakers are essential if you want a louder sound, surround sound, fuller bass, or just higher quality audio. The first internal computer speaker (a speaker inside the chassis of a laptop) was created in 1981 by IBM. External computer speakers began to appear in stores in the early 1990s when computer gaming, digital music, and other forms of media became popular. Some computer speakers are wireless nowadays, connecting to the computer via Bluetooth.

Notes:- You can turn your speakers (or headphones!) into a microphone. The difference between computer speakers and a microphone is that the frequency of the vibration originates from external sounds rather than data from a computer.

5. Projector

Mode: Visual

Function: A projector is an output device that enables the user to project the output onto a large surface such as a big screen or wall. It can be connected to a computer and similar devices to project their output onto a screen. It uses light and lenses to produce magnified texts, images, and videos. So, it is an ideal output device to give presentations or to teach a large number of people.

Modern projects (digital projectors) come with multiple input sources such as HDMI ports for newer equipment and VGA ports that support older devices. Some projectors are designed to support Wi-Fi and Bluetooth as well. They can be fixed onto the ceiling, placed on a stand, and more and are frequently used for classroom teaching, giving presentations, home cinemas, etc.

Popular Brands: BenQ, Sony, Optoma, Epson

Origin Story: Originally, projectors weren’t an output device. Projectors were first created and used in late 19th-century France. Throughout history, biunial lanterns were used to project ink on glass by photographers, lecturers, and magicians. A biunial lantern is a lantern with projection capabilities. "Biunial" means combining two things into one, so a biunial lantern is a directional lantern and a glass slide with a print on it for projecting.

In the early 1920s, filmstrips were used to show “films” in classrooms. Turning the knob allowed teachers to stop on specific slides. Clear film copies for projectors weren’t invented until the 1960s, and 3M became the leading producer in clear film and projectors.

The data projector was invented in 1980. This is the first year it was considered an “output device.” The data projector was the first rendition of the projector that was closest to modern-day. Using a single cathode ray tube (CRT), the first data projector projected only monochromatically.

Nowadays, projectors are typically used for presentations, watching movies, or as a teaching aid, as they enable an entire roomful of people to see images generated by a single computer. Modern projectors usually connect to the computer via an HDMI (high-definition multimedia) cable or VGA (video graphics array) cable.

A digital projector can be of two types:

Liquid Crystal Display (LCD) digital projector: This type of digital projectors are very popular as they are lightweight and provide crisp output. An LCD projector uses transmissive technology to produce output. It allows the light source, which is a standard lamp, to pass through the three colored liquid crystal light panels. Some colors pass through the panels and some are blocked by the panels and thus images are on the screen.


Digital Light Processing (DLP) digital projector: It has a set of tiny mirrors, a separate mirror for each pixel of the image and thus provide high-quality images. These projectors are mostly used in theatres as they fulfill the requirement of high-quality video output.As its name suggests, this output device "projects" computer images or video onto a wall or screen.

Notes:- 3D projectors are designed to project two images of the same thing from different angles at the same time. Wearing 3D glasses, the viewer can see a 3D projection composed of multiple superimposed images.

6. GPS (Global Positioning System)

Mode: Data

Function: GPS is a radio-based navigation system that’s composed of a sender computer and a receiver. The sender broadcasts signals to 24 satellites that ping to the sender the exact location of the sender computer in the form of latitude and longitude coordinates. The satellites use microwave signals to “talk” to the GPS, giving information on location, vehicle speed, and a number of other pieces of data.

Popular Brands: Magellan, Garmin, TomTom

Origin Story: A Soviet-era technology, GPS was originally used in the 1960s to track U.S. submarines carrying nuclear missiles. The Department of Defense deployed more satellites to bolster the burgeoning navigation system. By 1993, 24 satellites were in orbit and GPS was used broadly across the world in agriculture, aviation, the military, athletics, science, and the list goes on.

Notes:- Until May 1st, 2000, high-quality GPS signals were confined for use by the government.

7. Sound Card

Mode: Sound

Function: The sound card controls the output of sound signals, enabling devices like speakers and headphones to work. The sound card is known as an expansion card, which means it can be added to the motherboard. Although a sound card is not essential to a computer's basic functionality, you need one if you wish to play games, watch movies, listen to music, and use audio and video conferencing.

Popular Brands: Audigy, ASUS, Creative, EVGA

Origin Story: The first sound card was invented by Sherwin Gooch in 1972 and was used in PLATO systems (Programmed Logic for Automatic Teaching Operations). PLATO was the first computer-assisted learning system in widespread use. It wasn't until 1988 that sound cards were widely used in PCs.

When computer data is sent through a sound card, it is sent to the card digitally. The sound card then translates the digital information (in the form of binary, or 0s and 1s) into analog information: vibrations, output in the form of sound.

Notes:- The popularization of sound cards originated in the gaming realm. Sierra Entertainment, a gaming platform, began supporting add-ons like sound cards and this enabled the sound card industry to grow without being an underground solution to a growing issue: shallow sound while gaming.

8. Video Card

Mode: Visual

Function: As with the sound card, the video card is an expansion card that slots into the motherboard. The video card processes images and video, enabling visuals to be seen on a display. Most computers have basic video and graphics capabilities built into the computer's motherboard, but for faster, more detailed graphics, a video card is required.

Popular Brands: NIVIDIA, ASUS, MSI, EVGA

Origin Story: Video cards are also known as GPUs or graphics processing units. Before modern-day GPUs, IBM introduced the MDA (monochrome display adapter). The MDA supported visuals such as text and lines for uses such as drafting but didn't offer any graphical experiences.

In order to increase the functionality of the burgeoning computing technology, Hercules Computer Technology invented the Hercules Graphics Card, which integrated with the MDA to offer a bitmapped (or "rasterized," or pixelated), graphics experience. From the 1990s on, graphics technology was increasingly like modern-day graphics cards and has increased in graphic quality and speed significantly since then.

Notes:- Video cards can work in both 2D images and 3D images. Images like browsers, computer desktops, and PDFs are considered 2D images, whereas computer games are considered 3D.

9. Braille Reader

Mode: Print

Function: A braille reader is a peripheral device that enables a blind person to read text displayed on a computer monitor. The text is sent by the computer to the device, where it is translated into a braille format and made readable by pushing rounded pins up through a flat surface. Braille readers are also called braille displays and come in various sizes. Braille readers come in the form of separate devices from a keyboard or as part of a keyboard. Most use piezoelectric technology, or electricity generated by mechanical stress, to create a single line of text at a time in the form of raised bumps.

This was the case until late 2018 when Blitlab proposed an electronic solution to the limited capabilities of braille readers. Blitlab, upon its release, will allow the visually impaired to use the internet and read books and newspapers more independently. The technology is still in development. The device will cost only around $500, which is little compared to traditional braille readers, which cost around $5,000 to $11,000.

Popular Brands: ALVA, Handy Tech, Freedom Scientific, BrailleNote

Origin Story: Braille is a 63 character alphabet invented in 1824 by Louis Braille. Braille was embossed on paper and other materials for decades before braille reader technology was invented. The first braille output technology was patented in 1975 by the Schönherr Company, and braille reader technology has evolved slowly since.

Notes:- Blitlab is the first tablet-style braille reader technology that will utilize a perforated glass screen that raises bumps as the computer reads the text from websites and translates it to braille.

10. Speech-Generating Device (SGD)

Mode: Sound

Function: SGDs, also known as voice output communication aids, generate text to speech. A user types something and when the command is sent, the SGD reads the sentence out loud.

Popular Brands: DynaVox, Luminaud, ZYGO Industries, Inc.

Origin Story: The first version of the SGD used print output. The “patient-operated selector mechanism,” or POSSUM, found symbols on a display and illuminated them for the reader. In the 1980s Dynavox was formed by students from Carnegie Mellon University with the goal to make an effective SGD for a young woman with cerebral palsy. This resulted in the invention of the EyeTyper, a device that allowed the user to spell with their eyes that would then be spoken.

Notes:- The most famous use of an SGD was by Stephen Hawking. Hawking was an astrophysicist with Lou Gehrig’s disease (also known as ALS). Lou Gehrig’s disease slowly deteriorates nerves in the spine and brain that results in gradual loss of muscle control. This often includes the ability to speak.

Devices That Both Output and Input Data

•  Modem: A modem sends and receives information over a telephone line or cables.

•  Touch Screen: Touch screens accept input in the form of touch and display the output from the computer.

•  Network Card (NIC): A network card is an expansion card for a computer that allows the device to connect to the network or internet.

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Ved Prakash

Hello guys, I am Ved, from Dehradun, A MCA student of Graphic Era University Dehradun. Graduated with BCA In 2014 from VEER KUNWAR SINGH University. My Professional Career Start Early At My 2nd University Year of BCA, Utilizing My Passion for Computer System, I Start Working as Computer Teacher at Unisoft Solutions. I spend most of my free time reading books, articles and papers. Hundreds of books and thousands of hours serving online helped me expand my knowledge of the world and improve my understanding of what, I do..

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