Introduction to Computers/Output Devices
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Introduction to Computers → Output Devices
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Completion status: this resource is well on its way to completion, but there may still be work to do. |
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In order to make use of a computer, some form of output must be used to allow the user to understand what is going on inside the machine.
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[edit] Auditory
A computer can produce sound in the form of beeps from the piezo speaker on its motherboard, or it can use a sound card to produce true tone sounds that sound like the real thing.
[edit] Speakers
This is the primary method of sound output in most computers today. Sound is translated from bits to electrical signals in a sound card, which then channels the signals to the speakers.
[edit] MIDI
-MIDI (Musical Instrument Digital Interface) -Allows electronic musical instruments and computers to communicate, control and synchronize w each other -was invented in 1983 -It transmits digital data -Dave Smith is generally regarded as the "Father of MIDI" w:en:MIDI It is important because it enables people to work with audible sound.
Unlike mp3 or WAV files, MIDI does not transmit an audio signal or media, instead, it simply transmits digital data "event messages" such as the pitch and intensity of musical notes to play, control signals for parameters such as volume, vibrato and panning, cues and clock signals to set the tempo. Therefore, the "music" you get from midi files are simple instrumental sounds.
[edit] mic
Also known as "microphone": a device used to change sound into electric signals. Microphones are used in telephones, tape recorders, hearing aids and many other devices. w:en:Microphone
Capture waves in air, water (hydrophone) or hard material and translating them into an electrical signal is what a microphone was designed to do. w:en:Microphone
Microphones are also used to amplify sound waves making the original source louder.
Thomas Edison made the carbon microphone(transmitter)in 1876. [1]
[edit] printer
A printer is a device that prints text or images on paper. [2]; It makes a physical copy of it with ink on paper.
[edit] laser
A laser printer shoots a laser beam onto a rotating drum that picks up toner where the laser hits, and rolls that toner onto paper, which can then be heated (to make the toner stick).
[edit] Plotter
A plotter is a vector graphics printing device that connects to a computer.
Vector graphics could be considered as points, lines, curves, and polygons, which are all based upon mathematical equations to represent images in computer graphics. Raster graphics, by comparison, are known to the computer as just a bunch of dots. Raster graphics lose their sharpness if made too big, but vector images can be expanded indefinitely. w:en:Plotter
[edit] Pen
Pen Plotters print their output by moving a pen across the surface of a piece of paper. This means that plotters are restricted to line art, rather than raster graphics as with other printers. They can draw complex line art, including text, but do so very slowly because of the mechanical movement of the pens.
Early plotters worked by placing the paper over a roller which moved the paper back and forth for X motion, while the pen moved back and forth on a single arm for Y motion. w:en:Plotter
[edit] Electrostatic
An Electrostatic Plotter produces a raster image by charging the paper with a high voltage. This voltage attracts toner which is then melted into the paper with heat.
This type of plotter is fast, but the quality is generally considered to be poor when compared to pen plotters.
[edit] Large-format
[edit] monitor
[edit] dot pitch
Is the space between the centers of pixels that are adjacent to each other. If the pixels are closer together the image will be crisper. A dot pitch of 0.25dp will provide clear images. Essentially, it is the distance between pixels.
[edit] resolution
Resolution in monitors is measured in pixels. The amount of pixels and the size of the monitor can determine how sharp the picture is. Pixels are aligned in columns and rows in the display. So the more pixels you have the better the display will be. w:en:Display_resolution
The resolution of scanners can vary by 1000's of dpi's( dots per inch ). Resolution refers to the visuals of an image ( IE. clarity and sharpness ).
[edit] colour depth
Amount of bytes used to create the exact colour of one pixel. 1 byte can produce 256 colours. Usually 2 or 3 bytes are used in images stored as photographs.
[edit] refresh rate
Refresh rate refers to the number of times the image on a monitor (screen) is redrawn each second. Essentially, it is the number of times per second that the pixels are recharged so that their glow remains bright. If the refresh rate is higher, the image on the screen will look more solid and flicker less. Typically, most screens have a refresh rate of between 56-120 times per second.
[edit] CRT
Cathode Ray tube, shoots electrons onto a screen.
[edit] flat panel
[edit] passive matrix
Refers to the panel display, and can give us information about where their transistors are located. A passive-matrix diplay provides a sharp image for one-color(monochrome) screens, but is more subdued for color. By referring to passive-matrix display, this tells us that the transistor controls a whole row or column of pixels on the flat-screen display. The advantage to passive-matrix display is that they are less expensive nad use less power. The most-common abbreviations used to refer to passive-matrix are HPA, STN, DSTN.
[edit] active matrix
Active Matrix is a type of liquid crystal display used in note book computers as it is very portable and lightweight.w:en:Active_matrix It is also know as TFT (thin-film transistor).Active-matrix are brighter and sharper than passive-matrix screens. They are more expensive and require more power which can affect battery life in laptop computers.
