Section 2 - Input and output devices Flashcards
What are ‘input devices’?
Hardware devices that allow data to be entered into a computer
What are the two types of input devices?
Manual input devices
Direct input devices
Manual input devices
Data is input into the computer by hand (people have to do most of the work).
Keyboard
- Text, numbers and instructions
- Used to input data into applications
- Used to enter commands into the computer.
Numeric keypads
- Used to enter numbers into a computer system
- Used in: ATMs, telephones, chip and pin devices
Pointing devices
- Used to control a cursor on a screen.
- Mice:
Opening, closing, maximising and minimising programs and files
Moving, grouping and deleting files
Using applications - Touchpad:
Replacement of mouse
Same uses as mice - Tracker ball:
Same functions as mice
More comfortable to use than mice
Some arcade gaming machines use tracker ball’s to control gaming characters on screen.
Remote control
- Used to control other devices using infrared signals
- Home entertainment systems use remote controls: DVD / Blu-ray players, TV etc.
- Industry uses remote controls to operate machinery that might be too dangerous to get near to: activating explosives in demolition.
Joysticks
- Similar functions to mice and trackballs.
- Can control characters or objects in video games
- Can control industrial machinery
- Used in simulators.
Touch screens
- Input commands into a computer by pressing or touching buttons / icons on the screen.
- Users can touch or press icons on the screen removes the need to use a mouse.
- Mobile phones and PDAs use touch screens.
- Interactive whiteboards in schools.
Scanners
- Used to enter information on paper into a computer.
- Reflects light off the hard copy in order to capture an analogue image of the document then converts it to digital format.
E.g. old photograph (analogue) -> scanner converts photo into digital data -> digital data can be stored on a computer.
Graphics tablet
- Used by artists and designers to easily create and store digital graphics in a computer
- Whatever is drawn onto tablet can be seen on a computer screen.
- Allow designers to produce digital images much more accurately than if they were using a mouse.
Light pens
- Used by directly drawing or selecting icons on a computer screen.
- Works by: Picking up light from the computer screen + signaling to the computer exactly where light picked up
Microphones
- Used to input analogue sounds into a digital computer.
- Used in voice recognition software.
- Used in gaming so that gamers can talk to each other.
Digital cameras
- Store digital photographs on a memory card.
- Built-in screen to allow for previewing
- Capture video and sound
- Exists in almost all modern mobile phones.
Web cameras
- Used to conduct face-to-face conversations such as Skype.
- Video-conferencing
- Capture image and video content
- Alternative to security cameras.
Direct input devices
Data is input into the computer directly by a machine / device.
Barcode readers
- Reads and outputs printed barcodes to a computer.
- Used in supermarkets, stores
Advantages + disadvantages of barcode readers
ads:
- Quick & easy to change products price (all digital)
- Easy to get info on system (only have to scan)
- Automatic stock control.
- Very accurate->no typing
disads:
- Expensive(each item needs a barcode / computer technology / database needed)
- Can only read undamaged barcodes
- Barcodes can be swapped.
Optical mark readers (OMR)
- Captures human-marked data
- Often used to read multiple choice examinations where students shade in areas they think are correct.
Advantages + disadvantages of OMR
ads:
- Very fast method of marking because it is automatic.
- Accurate because it automatically transfers data.
- Can save money from employing people
disads:
- Forms need to be accurately designed.
- Can only read shaded areas.
- If forms are filled incorrectly, they cannot be read.
Magnetic ink character recognition (MCR)
- Read information printed in a special ink, then convert it into form that computer can understand.
Write customer account numbers on cheques.
Advantages + disadvantages of MCR
ads:
- Cheques can be processed very quickly.
- Special ink characters cannot be changed, increases security.
- No manual inputs -> less errors.
disads:
- Only limited characters can be read.
- More expensive than other devices.
Magnetic Stripes Reader
- Read magnetics stripes that are found on back of credit cards, loyalty cards etc.
- Magnetic strips contain the user’s personal details such as account no, and name.
Advantages + disadvantages of magnetic stripes reader
ads:
- Simple for people to use.
- Cards are inexpensive to make.
- Data on the card can be altered.
- Security is improved by PIN numbers.
disads:
- Limited storage for data.
- Data can be destroyed by strong magnetic fields.
- Not always secure because thieves can read the data on the card.
Biometric devices
- Use fingerprint and retinal identification.
- Identify at ATMs to withdraw cash, or register you at schools.
- Devices capture the biometric data => then passed to a computer for processing and identification.
Advantages + disadvantages of biometric devices
ads:
- Security because only you can confirm your identity
- Convenient since no need for passwords.
disads:
- Injuries can lead to false biometrics.
- Expensive
- Can be hacked
Optical character reader (OCR)
- Consists of a scanner + special software
- Lets us scan text on paper into a computer
- Into computer, OCR software converts scanned text into a digital format
Advantages + disadvantages of OCR
ads:
- Fast way of entering hard-copy text into a computer
- Cheaper than paying an employee to manually re-type printed text into a computer
- Avoids typing errors as the process is automatic
disads:
- The system can have difficulty reading handwriting
- Not 100% accurate
- Needs to be manually checked for errors -> time consuming
Chip and PIN reader
- Used in debit cards (chip implanted)
- Compare stored info in the card and compare it to the PIN number typed in by user.
What are ‘output devies’?
hardware devices that allow information to be sent out of a computer system.
Temporary output
a computer monitor produces images on the screen that constantly refresh and change
Permanent output
a printer produces outputs as hard copies on paper.
CRT monitor
- Stands for ‘cathode ray tube’
- Old, bulky, heavy monitors
- Becoming rare as TFT monitors are replacing them.
CRT monitor uses
- Allows users to see outputs from the computer
- Used with light pens to allow drawings to be created on screen
Advantages + disadvantages of CRT monitor
ads:
- Can be used with light pens to create drawings on screen
- Larger range of colours than TFT monitors
- Screen angle is better than with TFTs
- Cheaper than TFT screens
disads:
- Very large and bulky
- Create a lot of heat
- Screen glare makes viewing difficult
- Need more power than TFTs to operate
TFT monitor
- Stands for ‘thin film transistor’
- Thin flat screened monitors that are commonly seen today
- Most popular computer screens
TFT monitor uses
Used as screens in laptops, computer, mobile phones
Advantages + disadvantages of TFT monitor
ads:
- Lightweight so perfect for portable laptops
- Very thin and take up less space
- Produce much less glare than CRT
- Less power
- Emit less radiation
- Produce less heat
disads:
- Images can appear unclear when viewed from an angle
- Lower picture quality
- Cannot be used with Light Pens yet
Laser printer
- Produce high quality hard copy outputs
- Use toner pressed on a page to produce printed documents
- Can print large amounts of pages at a very quick rate
- Work by using a laser beam to ‘draw’ onto a drum
Laser printer uses
Used in schools, businesses, offices
Advantages + disadvantages of laser printer
ads:
- Very fast at printing documents
- Toner cartridges last a long time
- Can handle high volumes of printing
- Very quiet
- Very high quality
- Reliable
- Cheaper to run than inkjets
disads:
- Environmentally unfriendly (produces ozone)
- More expensive to buy
- Colour laser printers are much more expensive to buy than inkjets
- Larger in size compared to other types of printers
Inkjet printer
- Produce high quality hard copies on paper
- Quality not as good as laser printers, but better than dot matrix
- Have small amounts of internal memory (RAM) to store print jobs printing slow
Inkjet printer uses
- Good where few printouts are needed
- Ideal for single-page, very high quality
- Often used to print photographs
Advantages + disadvantages of inkjet printer
ads:
- Output is very high quality
- Much cheaper to buy than laser printers
- Smaller than laser printers so take up less space
- Very quiet whilst printing
disads:
- Slow printing rates
- Ink cartridges don’t last long, not suitable for large print jobs
- Expensive to run
- Printouts can easily smudge if document not left to dry properly
Dot matrix printer
- Slow, noisy and produce poor quality outputs
- Work by using a set of pins to press an inked ribbon against paper
Dot matrix uses
- Very robust and can be used in noisy and dirty environments
- Used in environments where print speed and noise is not an issue
Advantages + disadvantages of dot matrix printer
ads:
- Work fine in dusty + dirty environments
- Very cheap to buy and maintain
- Good for continuous printing
disads:
- Very noisy
- Very slow
- Very poor quality
Wide format printer / plotter
- Two types: drum and flatbed
- Are capable of printing on very large pieces of paper
- High quality
- Draw images on page using coloured pens
Plotter uses
- Used to produce large, accurate drawings like:
Blueprints of buildings
Maps
Giant posters and adverts
Advantages + disadvantages of plotter
ads:
- Can produce much larger printouts than other printers
- Print quality is extremely high
- Can ‘cut out’ designs for use in sign making
disads:
- Print times are very slow
- Very expensive to buy and maintain
Speakers
- Connected directly to computer/are built into monitor
- Speakers are analogue
Speakers uses
- Output sound from multimedia presentations
- Home entertainment
- Can be used by blind people to listen to words on the screen
- Can be used play downloaded music files
Advantages + disadvantages of speakers
ads:
- Everyone in the room can hear the sound
- They can help blind people use a computer
disads:
- Output from speakers can disturb people trying to work
- High quality speakers can be expensive
Multimedia projector
- Project whatever appears on computer monitor onto large screen so a lot of people can view it
- Controlled using a remote control
Multimedia projector uses
- Large scale advertising of new products
- Home cinemas
- Training presentations
Advantages + disadvantages of multimedia projectors
ads:
- Many people to clearly view the same presentation
- Enhance the viewer’s experience
disads:
- Lower image quality compared to a computer screen
- Expensive to buy
- Cooling fans in the projector are noisy
