Karteikarten
Module 18
Karten in diesem Stapel (19)
- 1EXPLAIN LASER PRINTER?LASER PRINTERS:
- use a process known as electrostatic digital printing in combination with a laser beam to produce the image
- offer both monochrome & color printing
- duplex printing(dual-sided)
- Declining prices
- high quality(DPI(dots per inch) - more dots, better image) & rapid printing(PPM(pages per minute)) - 2EXPLAIN THE LASER PRINTER PROCESS?LASER PRINTER PROCESS:
- image-processing(digitized image is prepared to be transferred to a photosensitive drum)
- charging(uses a corona wire to apply a uniform negative 600V charge to the drum, which repulses all toner away from the drum)
- exposing(laser beam is focused on the drum which discharges areas of exposure, effectively draining the charge of the drum, & points exposed to the laser will now attract the toner)
- developing(occurs because of the difference in electrical charge, toner is now attracted to the area's discharged by the laser & still repulsed by areas where the charge remains)
- transferring(involves another corona wire that carries a positive charge which is positioned permanently beneath the paper and draws the negatively charged toner from the drum onto the paper
- fusion(uses a heated roller to literally melt the toner into the final image and press it into place)
- cleaning(wiper blade removes any remaining toner from the drum & static voltage on the paper)
- recharging(drum is exposed to an erase lamp which returns it to a neutral charge for the next job) - 3EXPLAIN INKJET PRINTERS & DOT MATRIX PRINTERS?INKJET PRINTERS:
- more common in the home environment
- users ink cartridges and print heads that move across the page
- with a focused ink spray of ink to produce the image
- two primary methods of doing this: continuous inkjet(common in manufacturing or producing labels with high quality) & drop-on-demand(common for home printing)
- main consideration for inkjet printers is the printing heads. Fixed head(print head is a component of the printer, designed to last for the life span of the printer, less expensive but if damaged you have to replace the whole printer) or disposable head(a component of the ink cartridge and is replaced every time you change the cartridge, expensive)
DOT MATRIX PRINTERS:
- work on impact principle where pins strike ink-soaked ribbon onto paper behind it
- largely replaced by inkjets
- still some current applications(maybe a point of sale, cash register, ATM
- tend to remain in use because of its ability to produce multiple copies simultaneously(ivoices have 1 copy for customer & 1 for vendor) - 4EXPLAIN THERMAL PRINTERS?THERMAL PRINTER:
- relies on heating thermal paper which turns black where you want the image to appear
- small & faster than dot-matrix(ideal for portable devices)
- common applications might include point-of-sale, label printing & gas station pump receipts
- might see some colour but usually only one other one(using 2 temperatures, one to produce black and the other to produce the color) - 5EXPLAIN FLATBED AND BARCODE SCANNERS?FLATBED:
- used for flat documents or photographs
- reflects light off an image itself and measures the intensity and color
- two main methods for this, Charged Coupled Device(CCD) scanner(uses a lens to reduce the image, higher quality, larger format) and Contact Image Sensor(CIS) scanner(a moving set of 3 RGB light-emitting devices, lower cost & format, common in homes)
- flatbed scanner computer connections = may have network connection, small computer system interface(SCSI), parallel port, firewire, universe serial bus(USB)
BARCODE SCANNERS:
- similar operation to a flatbed scanner
- components = light source, lens, sensor
- converts light impulses to electrical signals
- decodes the pattern of black/white bars
- key features may include = LED scanner, laser scanner, Omni-directional barcode scanners, smartphone-based scanners (camera-based)
- barcode scanner computer connections = may have a network connection, Wi-Fi/Cellular, USB - 6EXPLAIN 2 MAIN TYPES OF MONITORS?CATHODE RAY TUBE(CRT) MONITORS:
- the cathode is a negatively charged heated filament in a vacuum-sealed glass tube that fires electrons
- has a phosphor-coated screen that contains millions of tiny red, green, & blue dots that glow when struck by the electron beam
- bulky, heavy & big
LIQUID CRYSTAL DISPLAY(LED)
- users LED backlighting
- used for laptops(flat screen, low power consumption, lightweight, small size)
- replaced cathode ray tube technology for desktops
- ideal for high definition content
KEY CHARACTERISTICS OF LCD:
- screen resolution(resolution is the number of pixels on both the horizontal & vertical)
- aspect ratio(probably find ratios of 16 to 9 or 16 to 10)
- display size(measured from diagonal corner to diagonal corner)
- response time(amount of time it takes a pixel to go from black to white and back again or white to black and back again, measured in milliseconds)
COMMON FEATURES OF LCD:
- touch screen, glossy screen, curved screen, widescreen, directional screens, other accessory's(Connections - USB, headphone jack & Integrated - webcam/audio) - 7EXPLAIN VR HEADSETS?VIRTUAL REALITY(VR) HEADSET:
- computer-generated simulated environment
- separate imaging for each eye
- surround sound
- key applications = computer games, simulations & training
- other VR peripherals = head motion tracking, body motion tracking, eye tracking, game controllers - 8EXPLAIN EXTERNAL OPTICAL DISK DRIVES?EXTERNAL OPTICAL DISK DRIVES:
- size of a paperback book
- open close button(drive bay door)
- discs are fed into the drive
- operates with laser
- less commonly used
USES OF EXTERNAL OPTICAL DRIVES:
- reading and writing on optical discs
- used for CD's, DVD's and Blu-ray
- can be used to store large amounts of data
- can be used for archival - 9EXPLAIN MICE & KEYBOARDS?THE MOUSE:
- effective way to interact with the computer
- Connections = PS/2, USB, wireless
- Newer optical (no ball underneath, few moving parts, requires appropriate surface)
KEYBOARDS:
- effective way to enter data into a computer
- Connections = PS/2, USB, wireless
- extra features built in to interact with your computer(audio, monitor brightness) - 10EXPLAIN TOUCHPADS AND SIGNATURE PADS?TOUCHPADS:
- used in place of a mouse
- operated with fingers
- typically found on laptops(integrated into the surface, occupy very little space)
- stand alone external devices( connected via USB, Bluetooth)
SIGNATURE PADS:
- used to collect individual signatures
- Electronic signature linked to other data(name, barcode, photo, etc)
- backlit lcd(can view electronic writing, can navigate between screens)
-Applications = enhanced security, agreements, transactions - 11EXPLAIN GAME CONTROLLERS?GAME CONTROLLERS:
- provides input to video games
- characters or objects can be controlled
- can connect to computer with a USB/wireless
- earlier versions were very simple, multifunction controllers now
- require device drivers to operate on computers
KEY TYPES OF GAME CONTROLLERS:
- keyboard, mouse, joystick, gamepad, steering wheels, light guns - 12EXPLAIN CAMERAS & WEBCAMS?DIGITAL CAMERAS:
- high-quality imaging
- high-quality video & audio
- connecting to a personal computer = USB, memory cards, wireless network)
WEBCAMS:
- engage in interactive communication
- enable face to face communications(versus email or phone)
- allow for more influential conversation
- reduce risk of misunderstanding
- can be used to record content
- low cost and convenient - 13EXPLAIN MICROPHONE & SPEAKERS?MICROPHONES:
- convert sound waves to electrical signals
- can be used for real-time communication or recording
- can have external microphones
- integrated into laptops
- may have an analog microphone connection(uses tip/ring/sleeve connector)
- digital microphone connection(USB is more common)
SPEAKERS:
- converts electric signals to audio
- enable consumption of audio content
- laptops typically have integrated speakers
- external speaker connections = USB, 3.5 mm mini-jack, Bluetooth - 14EXPLAIN PROJECTORS?PROJECTORS:
- projects images & video
- projects onto a wall or screen
- projection surface should be flat
- projector surface should be lightly colored
- comes in various sizes
- applications = presentations, entertainment, computer screen projectors for demonstrations
PROJECTOR LUMENS & BRIGHTNESS
- primary factor is the brightness, the value for this is called lumens(amount of light output/brightness)
- lumens depends on ambient light you have to compete with(lower lumen for easy small room to turn the lights off in, higher lumen for large classroom where the lights may need to be on)
- common range: 1500 to 30000 lm
- different brightness modes - 15EXPLAIN EXTERNAL STORAGE DRIVES?EXTERNAL HARD DISK DRIVES:
- desktop external hard drive(3.5 inch) & portable external hard drive(2.5 inch)
- high capacity
- connections USB 2.0/3.0/eSATA
- good for mass storage & archiving
- relatively cheap & reliable
EXTERNAL SOLID STATE DRIVES:
- data is stored in non-volatile memory
- no mechanical/moving parts
- lower power consumption
- very reliable & robust
- operates faster than hard disk drives
- more reliable than hard disk drives
- high capacity
- connections = USB 2.0/3.0
NETWORK ATTACHED STORAGE:
- usually see in a network environment with large demands on storage
- multiple hard drives housed in an array storage enclosure(rack of hard drives)
- accessed over a network(ethernet port)
- ideal for large scale data backups(automated process)
- high capacity
- enables Redundant Array of Independent Disks(RAID)
- can be costly
- limitations of local backup (desktop level)
THUMB & FLASH DRIVES:
- small size, no mechanical parts, highly robust, low capacity, portable
EXTERNAL OPTICAL DRIVES:
- CDs & DVDs
- low capacity
- cheap
- low read/write speeds
- not as reliable - 16EXPLAIN KVM?KVM SWITCH:
- stands for keyboard, video & mouse
- physical device that allows the user to control multiple computers with a single set of peripherals(mouse/keyboard/monitor)
- physical switch to change between computers
- was common in data centers
- less common since the proliferation of virtual machines & remote desktop connections
TYPES OF KVM SWITCHES:
- when a USB device is plugged in, the computer invokes an enumeration process to detect the device and maybe run a short initialization process before it can be used
- Hub Base Class(enumeration process is re-invoked every time, 10-15 sec latency),
- Emulated Class(had software emulators so programmable features such as hotkeys on the keyboard will be maintained as you switch from system to system, latency issue reduced)
- Semi-DDM Class(uses enhanced emulators & dynamic device mapping which support any type of USB human interface device, still latency)
- DDM Class(uses dedicated fully functional emulators across all systems to retain all device functionality for every system, virtually no latency when switching systems) - 17EXPLAIN MAGNETIC AND CHIP READERS?MAGNETIC STRIPE:
- reads information from cards with magnetic stripes
- data is encoded into the magnetic stipes
- connections = serial port, USB, keyboard wedge(built-in, common)
- information is written with an encoder(using a electromagnetic writer using electrical charges to produce a magnetic field)
- reading information(changes in the magnetic field are red & that is how the information is decode)
CHIP READERS:
- used to read smart cards
- is any type of card with a built-in chip
- reader types = contactless(uses near-field communication) or insertion
- typically used for payment cards - 18EXPLAIN NFC?NEAR-FIELD COMMUNICATION(NFC):
- enables the communication between devices
- uses radio-frequency identification technology(RFID)
- communcation distance limited to centimetres
- not entirely secure as still a transmission(can be picked up on(eavesdropping), if so data can be modified, there are protective containers that can be used to secure your cards though)
COMMON APPLICATIONS OF NFC:
- contactless payment systems
- commonly used for sharing data, pictures, and contacts between mobile devices(referred to as bootstrapping or android call this beaming)
- used in identity & access tokens(still smart cards but for access to secure locations)
- Gaming(multi-player games on a mobile device, if close to a friend, you could play against each other using NFC) - 19EXPLAIN SMART CARD READERS?SMART CARD READERS:
- data storage ability(a lot of information can be stored than on say a magnetic stripe)
- readers support contact and/or contactless using NFC
- commonly used to store personal identification for access to secure locations
- chip itself is tamper-proof as if someone tries to physically access the chip in order to circumvent the information stored on it, it will self-destruct/be unusable
- can act as a secure data repository for the information on that chip
COMMON USES OF SMART CHIPS:
- banking & retail, electronic wallet, ID verification, Access control, Healthcare
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- Learning Technology Specialist CompTIA A+ (Core 1) Karteikarten am Module 18, erstellt von Chantelle Knight am 14/09/2021.
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- Chantelle Knight
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