3.2 input and output devices Flashcards
(40 cards)
what is an input device
a device that allows you to pass information from outside world into computer system
what are examples of input devices
- barcode scanner
- digital camera
- keyboard
- microphone
- optical mouse
- qr code scanner
- touch screen (resistive, capacitive, infra-red)
- 2d/3d scanner
use of 2d scanner do
input hard-copy documents
use of 3d scanner
- scan solid objects
- produce 3d image
use of barcode scanners
- scanning goods at supermarket checkout
- checking library books in/out
use of qr codes
- access websites
use of digital camera
- integrated into almost all smartphones
- professional photography
- security/surveillance systems
why is digital camera required
- replaced traditional film based cams
- instant photos, no development required
- digital photos can be easily transmitted via wifi, bluetooth, etc
why is barcode scanner required
- faster checkout q
- less error caused by manual input
- automatic stock control
what does keyboard do
input text and numerical data
what does optical mouse do
input movement to control cursor
what is optical mouse used for
navigation and interaction with almost all elements of graphical user interface (GUI)
what does microphone do
allows input of sound data
why is microphone required
capture sound and store as digital approximation
explain resistive touch screen
- 2 conductive layers
- layers separated by insulating layer
- when screen pressed, metal sheets touch, complete electrical circuit
explain infrared touch screen
- grid of IR light over screen
- when screen touch, beams broken
explain capacitive touch screen
- composed of protective layer, transparent conductive layer, glass substrate
- touch changes electrostatic field of conductive layer
what is an output device
device that can take data stored in digital form and convert into another form humans can process
what are the output devices
- actuator
- digital light processing/liquid crystal display projector
- inkjet/laser printer
- light emitting diode/liquid crystal display screen
- speaker
- 3d printer
what are actuators
carry out physical movement
DLP vs LCD projectors
- DLP higher contrast ratios
- DLP smoother video
- DLP smaller, lighter, more portable
- DLP better suited to dusty/smoky atmospheres
- LCD sharper images
- LCD better colour reproduction
- LCD less expensive
- LCD quieter
- LCD less power usage and heat production
LED vs LCD screen
LED better because
- better img quality and viewing angles
- longer lifespan
- no additional backlighting, thinner and lighter
what is a sensor
specific type of input device, measure physical properties of environment automatically and continuously
how is analog data converted into digital format
analog-to-digital converter (ADC)
