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Input And Output Devices Computer Science Essay

Paper Type: Free Essay Subject: Computer Science
Wordcount: 4502 words Published: 1st Jan 2015

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The computer will be of no use unless it is able to communicate with the outside world. Input and Output devices are required for users to communicate with the computer. In simple terms, input devices bring information into the computer and output devices bring information out of a computer system. These input/output devices are also known as peripherals since they enclose the CPU and memory of a computer system.

A hardware device that accepts inputted information and also has the capability of outputting that information. Good examples of an input and output devices are a floppy diskette drive and a hard disk drive.

An output device is any piece of computer hardware equipment used to communicate the results of data processing carried out by an information processing system (such as a computer) to the outside world.

In computing, input and output, refers to the communication between an information processing system (such as computer), and the outside world. Inputs are the signals or data sent to the system, and output are the signals or data sent by the system to the outside.

The most common input devices used by the computer are the keyboard and mouse. The keyboard allows the entry of textual information while the mouse allows the selection of a point on the screen by moving a screen cursor to the point and pressing a mouse button. The most common outputs are monitors and speakers.

Output devices

Examples of output devices

Any peripheral that receives and/or displays output from a computer. To the right is a picture of an inkjet printer and a good example of an output device. Below is a listing of all the different types of computer output devices found on a computer.

Sound card

Video card





Features and Functions

Sound Card

D:MMU fileSEM 3Computer Applicationsound card.jpg

A sound card (also known as an audio card) is a computer expansion card that facilitate the input and output of audio signals to and from a computer under control of computer programs. Typical uses of sound cards comprise providing the audio component for multimedia applications such as music composition, editing video or audio, presentation, education, and entertainment (games). Many computers have sound capabilities built in, while others necessitate extra expansion cards to provide for audio capability.

Video CardD:MMU fileSEM 3Computer ApplicationVideo_Card.jpg

A video card, video adapter, graphics-accelerator card, display adapter or graphics card is an extension card whose function is to generate and output images to a display. Many video cards offer added functions, such as accelerated rendering of 3D scenes and 2D graphics, video capture, TV-tuner adapter, MPEG-2/MPEG-4 decoding, FireWire, light pen, TV output, or the ability to connect multiple monitors (multi-monitor). Other modern high performance video cards are used for more graphically demanding purposes, such as PC games.



A video projector takes a video signal and projects the corresponding image on a projection screen using a lens system. All video projectors use a very bright light to project the image, and most modern ones can correct any curves, blurriness, and other inconsistencies through manual settings. Video projectors are widely used for meeting room presentations, classroom training, home theatre and live events applications. Projectors are widely used in many schools and other educational settings, connected to an interactive white board to interactively teach pupils.



A monitor or display (sometimes called a visual display unit) is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure. The display device in modern monitors is typically a thin film transistor liquid crystal display (TFT-LCD), at the same time as older monitors use a cathode ray tube (CRT).


Computer speakers, or multimedia speakers, are speakers external to a computer that disable the lower fidelity built-in speaker. They often have a low-power internal amplifier. The standard audio connection is a 3.5mm (1/8 inch) stereo jack plugs frequently colour-coded lime green (following the PC 99 standard) for computer sound cards. A plug and socket for a two-wire (signal and ground) coaxial cable that is generally used to connect analogy audio and video components. Also called a “phono connector,” rows of RCA sockets are found on the backs of stereo amplifier and numerous A/V products. The prong is 1/8″ thick by 5/16″ long. A few use an RCA connector for input. There are also USB speakers which are powered from the 5 volts at 200 milliamps provided by the USB port, allowing about half a watt of output power.


In computing, a printer is a peripheral which produces a hard copy (permanent readable text and/or graphics) of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are first and foremost used as local peripherals, and are attached by a printer cable or, in most new printers, a USB cable to a computer which serves as a document source. Some printers, commonly known as network printers, have built-in network interfaces (typically wireless and/or Ethernet), and can serve as a hardcopy device for any user on the network. Person printers are frequently designed to support both local and network connected users at the same time. In addition, a small number of modern printers can directly interface to electronic media such as memory sticks or memory cards, or to image capture devices such as digital cameras, scanners; some printers are combined with a scanners and/or fax machines in a single unit, and can function as photocopiers. Printers that include non-printing features are sometimes called Multifunction printers (MFP), Multi-Function Devices (MFD), or All-In-One (AIO) printers. Most MFPs include printing, scanning, and copying in the middle of their features.

Advantages and Disadvantages of Output Devices


Output devices





Comparatively cheap and reliable, can display text and graphics in a wide range of colures. They are also quiet and do not squander paper.

No enduring copy to keep and unsuitable for users with visual problems.



The purchase cost is low and the running costs are very low.

They can print fairly quickly, particularly if you remember that multiple copies are being printed in one print run.

They are robust and can operate in harsh environments.

If several sheets of self-carbonating paper are placed into the printer then the impact will produce duplicate copies.

The printing quality is low – these printers produce low to medium quality black and white printing and can only print low resolution graphics.

Because of the impact of the pins against the paper, these printers can be quite noisy.



Enables a lot of people to be able to see something even from a distance

Image quality may not be as good when projected.



Cheap and generally available.  Capable of producing very high quality sound.

They are an analogue device so the digital sound signal has to be converted, usually by a sound card.

Input Devices

A hardware device that sends information to the computer. Without any input devices a computer would simply be a display device and not allow users to interact with it, much like a TV. To the right are a Logitech trackball mouse and an example of an input device. Below is a listing of all the different types of computer input devices found on a computer.

Example of Input Devices



Digital camera

Mouse (pointing device)





MIDI Keyboard

Features and Functions for input devices


In computing, a keyboard is an input device, partially modelled after the typewriter keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches. A keyboard typically has characters engraved or printed on the keys and each press of a key typically corresponds to a single written symbol. However, to produce some symbols requires pressing and holding several keys at the same time or in sequence. While most keyboard keys produce letters, numbers or signs (characters), other keys or real-time key presses can produce actions or computer commands.


D:MMU fileSEM 3Computer Application350__1_full_game_pad_001.jpg.png

A gamepad (also called Joypad or control pad), is a type of game controller held in the hand, where the digits (especially thumbs) are used to offer input. Gamepads generally feature a set of action buttons handled with the right thumb and a direction controller handled with the left. The direction controller has traditionally been a four-way digital cross (also named a Joypad, or alternatively a D-pad), but most modern controllers as well (or as a substitute) feature an analog stick.

Digital Camera


Most digital cameras function in much the same way as a traditional camera that uses film to record images, except that in place of the film, images are captured and preserved in the camera’s digital memory, which may be built-in or which may be on a detachable memory card.


In computing, a mouse (plural mice, mousses, or mouse devices.) is a pointing device that functions by detecting two-dimensional motion relative to its supporting surface. Physically, a mouse consists of an object held under one of the user’s hands, with one or more buttons. It sometimes features other elements, such as “wheels”, which allow the user to perform a variety of system-dependent operations, or extra buttons or features can additional control or dimensional input. The mouse’s motion typically translates into the motion of a cursor on a display, which allows for fine control of a Graphical User Interface.



A microphone (colloquially called a mic or mike) is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal .Microphones are used in many applications such as telephones, tape recorders, karaoke systems, hearing aids, motion picture production, live and recorded audio engineering, FRS radios, megaphones, in radio and television broadcasting and in computers for recording voice, speech recognition, VoIP, and for non-acoustic purposes such as ultrasonic checking or knock sensors.

Web Camimages4

A webcam is a video capture device connected to a computer or computer network, frequently using a USB port or, if connected to a network, Ethernet or Wi-Fi. The mainly popular use is for video telephony, permitting a computer to act as a videophone or video conferencing station. This can be used in messenger programs such as Windows Live Messenger, Skype and Yahoo messenger services. Other popular uses, which include the recording of video files or even still-images, are accessible via numerous software programs, applications and devices. Webcams are known for low manufacturing costs and flexibility, making them the lowest cost form of video telephony. The term ‘webcam’ may also be used in its original sense of a video camera connected to the Web ceaselessly for an indefinite time, rather than for a particular session, generally supplying a view for anyone who visits its web page over the Internet. Some of these, for example those used as online traffic cameras, are expensive, rugged professional video cameras.


A joystick is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. Joysticks are often used to control video games, and usually have one or more push-buttons whose state can also be read by the computer. A popular variation of the joystick used on modern video game consoles is the analogy stick. The joystick has been the principal flight control in the cockpit of many aircraft, chiefly military fast jets, where centre stick or side-stick location may be employed. Joysticks are also used for controlling machines such as cranes, trucks, submerged unmanned vehicles, wheelchairs, surveillance cameras and zero turning radius lawn mowers. Miniature finger-operated joysticks have been adopted as input devices for smaller electronic equipment such as mobile phones.


In computing, a scanner is a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image. Common examples found in offices are variations of the desktop (or flatbed) scanner where the document is placed on a glass window for scanning. Hand-held scanners, where the device is moved by hand, have evolved from text scanning “wands” to 3D scanners used for industrial design, overturn engineering, test and measurement, orthotics, gaming and other applications. Mechanically driven scanners that move the document are typically used for large-format documents, where a flatbed design would be impractical.

MIDI Keyboardimages2

A MIDI keyboard is a piano-style digital keyboard device used for sending MIDI signals or commands to other devices connected to the same interface as the keyboard. MIDI is an acronym for Musical Instrument Digital Interface (protocol). The basic MIDI keyboard does not produce sound. In its place, MIDI information is sent to an electronic module capable of reproducing an array of digital sounds or samples that resemble traditional analog musical instruments. These samples are also referred to as voices.

Advantages and Disadvantages of Input Devices


Input Devices




Digital Camera

No film is needed and there are no film developing costs

Unwanted images can be deleted straight away

Images are already digital and can easily be transferred to a computer and edited or transferred over the Internet

Special image editing software can allow a huge range of adjustments and special effects to be tried

Images often have to be compressed to shun using up too much expensive memory.



Easy to learn to use.  Very simple design so they can be reasonably priced.

Control can be a bit crude as the directions in simple joysticks are limited to forward, backwards, left and right.  Better models offer diagonal movement or better.



dependable for data input of text and numbers.

Usually supplied with a computer so no additional cost.

Specialized keyboards are available.

Users may be slow for not very accurate typists.

Slow for accessing menus etc. and difficult to use if you want to move objects around the screen.

Difficult for people unable to use keyboards through paralysis or muscular disorder.



Voice recognition software can be used to convert your voice into text or to control menu options on a phone system.

Stored audio files can take up a lot of memory.

Voice commands can be difficult to recognise by the software.


MIDI keyboard

Data from a musical instrument is easily captured and edited with a computer.

MIDI files are small.

MIDI files can be recorded on one type of instrument and played back on another.

Audio cannot be recorded directly as an audio file such as MP3.

The playback depends on the instrument/computer sound card so may not sound the same as the original.

Only the note and the timing are stored.



Ideal for use with desktop computers.

more often than not supplied with a computer so no additional cost.

All computer users tend to be familiar with using them.

They need a flat space close to the computer.

The mouse cannot easily be used with laptop, notebook or palmtop computers. (These need a tracker ball or a touch sensitive pad called a touch pad).



Flat-bed scanners are very accurate and can produce images with a far higher resolution than a digital camera.

Can produce very large image files which need a lot of computer memory to view and edit.

Types of Pointing Devices

pointing stick.jpg

The is a small number of examples of pointing devices are pointing stick, touch screen, touch pad, joystick. A pointing stick is a pressure sensitive small nub used like a joystick. It’s more frequently than not found on laptops embedded between the ‘G’, ‘H’, and ‘B’ keys. It operates by sensing the force applied by the user. The corresponding “mouse” buttons are commonly placed just below the spacebar. It is also found on mice and some desktop keyboards.

Touch Screen


A touch screen is a device embedded into the screen of the TV Monitor, or System LCD monitor screens of laptop computers. Users interrelate with the device by physically pressing items shown on the screen, either with their fingers or some helping tool. Touch screens could be used in couple with stylus pointing devices, while those powered by infrared do not require physical touch, but just differentiate the movement of hand and fingers in some minimum range distance from real screen.


A touchpad or track pad is a flat surface that can detect finger contact. It’s a motionless pointing device, commonly used on laptop computers. At least one physical button normally comes with the touchpad, but the user can also generate a mouse click by tapping on the pad. Advanced features include pressure sensitivity and special gestures such as scrolling by moving one’s finger along an edge.


Joysticks are often used to control video games, and usually have one or more push-buttons whose state can also be read by the computer. A popular variation of the joystick used on modern video game consoles is the analog stick. Joysticks are also used for controlling machines such as cranes, trucks, and underwater unmanned vehicles.

Types of Keyboard

What is Keyboard? Keyboard is a set of typewriter that enable to you to enter data into the computer. The key on the computer keyboard got alphanumeric keys, punctuation keys, and special keys. There are several types of keyboard. For examples, notebook keyboard, PDA stylus, Tablet PCs, Wireless keyboard, and Ergonomic keyboard. For notebook keyboard will with the screen and the CPU. Keyboards on laptops and notebook computers more often than not have a shorter travel distance for the keystroke and a reduced set of keys. They may not have a numerical keypad, and the function keys may be placed in locations that different from their placement on a standard, full-sized keyboard. The layout is based on the 104-key Windows design, except the keys are “crammed” into the available space. There is no numeric keypad, but you can see the labels on keys in the middle of the keyboard where it is superimposed (the letter “J” has the numeral “1” on it, K is “2”, and so on). The “Fn” key in the lower left is used to activate particular options when used in combination with the function keys at the top of the keyboard.


PDA Stylus


PDA stylus is a touch type keyboard. That a keyboard is needed for extensive typing, a person can use a fold up keyboard. The fold-up keyboards have all of the room of usual keyboards, yet still compact.

Tablet PCs Keyboard

Tablet PCs keyboard is the the majority common peoples in the world using. It use to type any data into the computer. It have a place for number keys, alphanumeric keys, punctuation keys, and special keys.

Wireless Keyboard


Wireless Keyboard is the newest keyboard that came out this few years. The keyboard can use without wire, but the others function are same with the normal keyboard that we use.

Ergonomic Keyboard


Ergonomic keyboard is computer keyboard designed with ergonomic considerations to minimize muscle strain and a host of related problems. An ergonomic keyboard may decrease muscle strain and reduce risk of Carpal Tunnel syndrome, but there is no clear evidence of benefit. After a user takes the time to adjust to this style of keyboard, these keyboards can make typing easier, faster and less awkward. The keys separated into two or three groups, allowing the user to type at a different angle than the typical straight keyboard.

Types of Printer

Printer is classified into 3 types. There are impact printer, nonimpact printer and specialty printer. The example of impact printer is Dot-matrix. Dot matrix printers are still commonly used in low-cost, low-quality applications like cash registers, or in demanding, very high volume applications like invoice printing.

dot matrix printer.jpg

The nonimpact printers have Inkjet and Laser. For the Inkjet, operate by propelling variably-sized droplets of liquid or molten material (ink) onto almost any sized page. They are the most ordinary type of computer printer for the universal consumer. The laser is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. But the price will more expensive than others.

laser.jpgliquid inkjet.jpg

Inkjet Printer Laser Printer

Specialty Printersmultifunction.jpg

The specialty printers have multifunction, plotters and thermal printers. A multifunction printer is an office machine which incorporates the functionality of multiple devices in one, so as to have a smaller footprint in a home or small business setting or to provide centralized document management/ distribution/ production in a large-office setting. A typical multifunction printer may act as a combination of some or all of the printer, scanner, photocopier, fax and email.


Plotter is a computer printing device for printing vector graphics. In the past, plotters were generally used in applications such as computer-aided design, though they have generally been replaced with wide-format conventional printers. It uses a pen that moves over a large revolving sheet of paper.

Thermal Printerthermal.jpg

A thermal printer produces a printed image by selectively heating coated thermo chromic paper, or thermal paper as it is generally known, when the paper passes over the thermal print head. The coating turns black in the areas where it is heated, producing an image. Two-color direct thermal printers are capable of printing both black and an supplementary color (often red), by applying heat at two different temperatures.

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Types of Monitor

Monitor is an output device that resembles the television screen and uses a Cathode Ray Tube (CRT) to display information. The monitor is associated with a keyboard for guide input of characters and displays the information as it is keyed in. It also displays the program or application output. Like the television, monitors are also available in different sizes.

Liquid Crystal Display (LCD)

LCD was introduced in the 1970s and is now applied to display terminals also. Its advantages like low energy consumption, smaller and lighter have paved its way for usage in portable computers (laptops).

Devices used to get sound, video, and images into the computer

Video capture is one of the most important hardware to be used for multimedia work on a personal computer. Video-capture results will depend on the performance and capacity of all of the components of your system working together. Video capture from analog devices like video camera requires a special Video capture card that converts the analog signals into digital form and compresses the data. Video-capture card use various components of the computer to pass frames to the processor and hard disk. For high-quality video, a video-capture card must be able to capture full-screen video at a high rate. For example for a full-motion video, the card must be capable of capturing about 35 frames per second at 720 by 480 pixels for digital video and 640 by 480 for analog video. To determine what settings will produce the best results for your projects, you must be careful in defining these parameters.

A sound card is a device that attaches to the motherboard to enable the computer to input, process, and deliver sound. The sound card generates sounds; records sound from analog devices by converting them to digital mode and reproduce sound for a speaker by reconverting them to analog mode. Creative Lab’s Sound Blaster is a standard sound card, to the extent that some people use the name as a generic term.

A video adapter provides extended capability to a computer in terms of video. The better the video adapter, the better is the quality of the picture you see. A high quality video adapter is a must for you while designing your multimedia project.


Described is an input and output device for inputting or outputting data of an electronic equipment. The input and output device is designed for being detachably mounted to the electronic equipment in at least two different positions. The input and output device features a first contacting arrangement which, independent of the selected position in the mounted state of the input and output device on the electronic equipment, electrically comes in connection with a second contacting arrangement present on the electronic equipment. In one embodiment, orientation of the device may be varied, thereby enabling it to be coupled to a receiver by a bayonet connection and with a set of contacting arrangement engaging the second contacting arrangement in any orientation. Furthermore, described is an operating and display module, as well as to a combination of an electronic equipment and an input and output device that can be detachably mounted thereto.


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