Output Flashcards
What do output devices do?
Take data produced by a computer and turn it into a human-readable form.
How do LCD displays work?
Liquid Crystal Display LCD:
• Contain groups of red, green and blue diodes to form each pixel.
• The screen is typically back lit using light emitted diodes.
What are some advantages of LCDs over other technology?
- They reach their maximum brightness almost immediately.
- Image is sharper with more realistic and vivid colours.
- LEDs are very small, screens can be much thinner in construction.
- They last almost indefinitely, which makes the screen more reliable.
- They consume very little power and therefore produce very little heat as well as reducing running costs.
What are some advantages of OLED screens over LCDs?
- Much thinner
- Brighter and need no back-lighting, so they consume less power, which translates into longer battery life in a portable device.
- LCDs can be slow to refresh, OLEDs respond up to 200 times faster
- Produce truer colours through a much bigger viewing angle, LCDs the colours darken and disappear if you look from the side.
What are some disadvantages to OLEDs over LCDs?
- Do not last as long, wear out four times faster than LCDs.
* Very sensitive to water, which is a potential problem in a cell phone.
How do inkjet printers work?
Spraying minute dots of ink onto paper to create an image, depending on:
• Resolution of the image
• Number of colour cartridges used.
• Quality of paper being use
What is a difference between the operating costs of a laser printer and an inkjet printer?
• Inkjet printers are sold at below production cost, the cost of ink cartridges is dramatically marked up.
What are some advantages to inkjet printers?
• They are cheaper to use than laser printers
What are some disadvantages of inkjet printers?
- Inkjet cartridges require frequent replacement
* They are slower.
What do laser printer use?
Dry powdered ink called toner.
How do dot matrix printers work?
Print head has a matrix of pins which strike the surface of the paper through an inked ribbon to form letters.
What is an advantage of using dot matrix printers?
- Useful when multi part stationery is required.
* Can operate in damp or dirty environment
What are some uses for 3-D printers?
- Creating spare or parts for obsolete equipment.
* Producing prototypes of new products.
What are some medical applications of 3-D printers?
• Manufacturing of prosthetic limbs
- Large reduction in cost and greater accuracy in matching limb to individual patient
• Reconstructive surgery
- Surgeon can try out a procedure to ensure actual surgery is more accurate, can produce very accurate parts for surgical procedures.
What are some applications of 3-D printers?
- Very old cars are likely to need parts no longer manufactured, using an existing part as a blue print it is possible to print new components at a fraction of the cost.
- Prototyping for design fashion and art can save huge costs.
What are RFID systems?
input/Output decices
How do RFID systems work?
- They use a transponder and a receiver
- The powered receiver emits radio frequency energy
- The transponder antenna in the bank card, mobile phone or tag becomes energised by radio waves
- The transponder can then send data to the receiver
What are some uses of RFID Tags?
- identification of people, animals, goods or valuables
- Shipping and supply chain tracking
- Banking systems
What are passive transponders?
No power source, rely on radio waves from the receiver for energy, they need to be placed very close to the receiver.
What are active tags?
Use larger battery powered beacon which can broadcast signal from afar.
What are actuators?
Motors that are commonly use din conjunction with sensors to control a mechanism.
How do speakers work?
- Digital data is sent from the computer to a digital analogue converter DAC, where it is converted into an analogue signal.
- Signal is then boosted with an amplifier and sent to the speaker.
