Computer Chapter #6 Notes

Pixels

(short form for picture elements) are the small dots that make the image displayed on the screen.

Digital Camera

A camera that captures photographs in digital memory. It stores the pictures and video it takes in electronic format instead of film. The process of how it stores data is considered digital. Allow the user to take still snapshots and record videos.

Plotters

A computer printer for printing vector graphics. Plotters are quite large when compared to a traditional printer and are also much more expensive than the traditional printers. Plotters are used to print designs of ships and machines, plans for buildings, and so on. Instead of toner, plotters use a pen, pencil, marker, or another writing tool to draw multiple, continuous lines onto paper rather than a series of dots like a traditional printer. Example: IBM 6182 Pen Plotter

Scanner

A device that captures the image of any printed page or graphics by digitizing it, producing an image made of tiny pixels of different brightness and color values and then can be stored electronically or as a digital file on the computer hard drive or an external storage device.

Web Camera

A digital camera that is connected to a computer. It can send live pictures once connected to a network such as the Internet. Various types of web cameras, some are plugged into computers through USB ports, but others are wireless. Additional features may include a microphone. Built-in sensors that can detect movement and start recording. Lighting to let you know that the camera is in use.

Input Devices

A hardware device used to submit Instructions and data into a computer. Allows users to communicate with the computer. Forms of input: audio, video, text and graphics and so on.

Trackball

A pointing device like upside down mouse. Has a ball on its upper side. This ball is moved by fingers or thumb and the pointer moves accordingly on screen. Remains stationary on your desk, the user do not need much room to navigate the trackball.

Mouse

A pointing device that detects motion relative to a surface. This motion is typically translated into the motion of a pointer on a display. Used to control the movement of the pointer/cursor which is located on the screen. Has 2 or 3 buttons that preform different functions.

Pointing Stick

A small rubber projection embedded between the keys of the keyboard. Some notebook computers such as the IBM ThinkPad will incorporate a pointing stick. The pointing stick acts like a little joystick that can be used to control the position of the on-screen cursor.

Plasma

A type of flat panel display common to a large TV displays—30 inches or larger. It is called "plasma" display because the technology utilizes small cells containing electrically charged ionized gases, or what are in essence chambers more commonly known as fluorescent lamps.

Keyboard

A typewriter-style device which uses an arrangement of buttons or keys to act as a mechanical lever or electronic switch. Following the decline of punch cards and paper tape, interaction via teleprinter-style became the main input device for computers.

Printers

Allows you to receive a physical copy (printed), which is considered output. There are two print orientations, which are landscape and portrait. The printer needs several colors of ink (cyan, yellow, magenta, and black) to make color images. Some photo-quality ink jet printers have more colors of ink.

OLED Monitor

An LED in which the emissive electroluminescent layer is a film of organic compound that emits light in response to an electric current. Used to create digital displays in devices such as TV screens, computer monitors, portable systems such as mobile phones, handheld games consoles, and PDAs.

Pointing devices

An input interface that allows a user to input spatial data to a computer. Examples are Mouse, Trackball, joystick and so on.

Dot Matrix Printer

An older printer, which was first introduced in 1970. This printer operates using dots to form an image. In a dot matrix image, the image quality is determined by the number of dots per inch. Has largely been replaced by cheaper, quieter, and faster nonimpact printers such as inkjet printers and laser printers, which also produce an output of far better quality (resolution).

Output

Any data that has been processed into something that is useful or meaningful. It can be displayed in many forms such as text, graphics, audio, and video.

Output Device

Any hardware component that conveys information to one or more people. Eg: Display devices, printers, speakers, headphones, and so on.

3D Printer

Can be very expensive and the object is printed in three dimensions. Model is built up layer by layer.

Joystick

Consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. Often used to control video games. Also used for controlling machines such as cranes, trucks, underwater unmanned vehicles, wheelchairs, surveillance cameras, and zero turning radius lawn mowers.

Mechanical Mouse

Contains a rubber or metal ball inside it. The movement of the cursor depends on the movement of the ball. Normally used on mouse pad, a small flat pad made of rubber or foam to provide easy movement for the mouse. It protects the mouse from dust and dirt and has been replaced by the optical mouse.

Optical Mouse

Contains zero moving parts such as the ball located inside of the Mechanical Mouse. Uses light and a small optical sensor to detect the motion of the mouse. May use a light sensor or laser technology.

Wireless Mouse

Does not require a wire to work. Transmits data using wireless technology like radio waves such as Bluetooth or infrared light waves. May need batteries. The receiver is connected to the computer through a USB port.

Microphone

Enters sounds into the computer. It can be attached to a computer to record sound (usually through a sound card or circuitry built into the motherboard). The sound is digitized and turned into numbers that represent the original analog sound waves, which then stored in the computer so as to process and playback it later.

Types of Scanners

Flatbed, Sheetfed scanner, and Handheld scanner

Flatbed

Has a flat, glass surface for scanning documents or other things. Consisting of a light source, a lens, and a light sensor translating optical impulses into electrical ones. Most flatbed scanners have an adjustable lid that can be raised to allow magazines, books, and other thick objects to be scanned.

CRT Monitor

Has cathode ray tubes that use an electron beam of varying strength to "paint" a picture onto the color phosphorescent dots on the inside of the screen. Heavy and use more electrical power than flat panel displays, but they are preferred by some graphic artists for their accurate color rendition, and used to be preferred by some gamers for faster response to rapidly changing graphics.

Inkjet Printer

Inexpensive, but the cost of consumables (ink cartridges and special paper) make them costly to operate in the long run for many purposes. Uses a liquid ink that's sprayed through a print head onto a piece of paper.

Input Devices Examples

Keyboard, Mouse, Trackpad, Joystick, Touch Screen, Light Pen, Scanner Digital Camera, and Graphics Tablet

Sheetfed Scanner

Like a fax machine mechanism. Pages are entered into scanner like a fax machine. Advantages: Smaller in size, more portable, takes less space. Disadvantages: It requires separate pages to scan. However, it cannot scan a book because of its layout. It can scan normal papers with a normal thickness only one at a time.

LCD Monitor

Liquid crystal display also called flat panel monitor Thin, light, low power consumption. Can be disposed of more safely than a CRT. Produce sharp, flicker-free images. Choices of backlight: eg: LED. LED monitors take the LCD one step further. They put a diode on the back that forces light through the layers for a sharper picture and better colors. It is said that LED monitors will last longer than LCD monitors.

Types of Mouse

Mechanical Mouses, Optical Mouse, and Wireless Mouse.

Display Devices

Presentation of information in visual form. The screen size of all display devices is measured diagonally across the screen, in inches. Not all of the screen area may be usable for image display, so the viewable area is also specified. The resolution of the monitor is the maximum number of pixels it can display horizontally and vertically (such as 800 × 600, 1024 × 768, or 1600 × 1200). Most monitors can display several resolutions less than its maximum setting.

Handheld Scanner

Small, lightweight, and portable scanner. Used to scan small amount of data such as short articles from newspapers. It is held in hand and is moved over the text page or image slowly and smoothly from start to end. Scan quality may be lower than flatbed or sheet-fed scanner. A mobile device such as cell phone provides the capability of a handheld scanner.

Trackpad (Touchpad)

Specialized surface that can translate the motion and position of a user's fingers to a relative position on the operating system that is made output to the screen. Common feature of laptop computers. Stationary input device as a substitute for a mouse where desk space is scarce.

3D T.V.

TV using basic principle. The TV makers have to produce two separate moving images and send one of them to the viewer's left eye and the other to the right. This concept will portray the proper illusion of 3D. The simplest way of achieving this is to display two different images on the TV screen (one for the left eye and the other for the right) and make viewers wear special glasses so each eye sees only one of them.

Audio Output Device

The sound is a type of energy made by vibrations. Computers also produce a sound output, ranging from simple beeps alerting the user, to impressive game sound effects, to concert quality music. The circuitry to produce sound may be included on the motherboard, but the high-quality audio output from a PC usually requires a sound card in one of the expansion slots, connected to a set of good-quality external speakers or headphones. Common audio output device: Speakers, headphones and earphones.

Dot Pitch (DP)

The spacing of the screen's tiny phosphor dots. A screen with a smaller dot pitch produces sharper images.

Touchscreen

The user can make choices and press button images on the screen. In ATM and in the latest smart phones, touchscreen is used to receive input from the user. The user enters data by the touch of his or her finger on different menu options or icons present on touchscreen.

Impact Printers

These printers have a mechanism that touches the paper in order to create an image. Printer technology has advanced greatly over the past few decades. Impact printers operate by having an element strike the paper. A dot matrix impact printer is the most common type still sold today

Laser Printer

Uses heat technology and specialized a powder called toner. Produces good-quality images of the same technology that photocopiers use. A drum coated with photosensitive material is charged, then an image is written onto it by a laser (or LEDs), which makes those areas lose the charge. Most laser printers are monochrome (one color only, usually black), but faster than inkjet printers