hardware Flashcards
1
Q
3D printer
A
- process starts from saved digital file that holds the blueprint of object to be printed
- object is then built by sequentially adding layers of a material (polymer, resin) until object is created
- fan cools each layer
2
Q
microphone
A
- microphone acts as a diaphragm
- the incoming sound wave causes vibration
- causing coil to move past a magnet
- electrical signal is produced
3
Q
laser printer
A
- a laser beam and rotating mirrors are used to draw image of the page on a photosensitive drum
- image converted into electric charge which attracts positively charged toner such that it sticks to the image
- electrostatic charged paper is rolled against drum
- charge pulls toner away from drum and onto paper
- heat applied in the fuser to fuse toner to the paper
- electrical charge is removed from drum and excess toner is collected
4
Q
speakers
A
- takes an electrical signal and translates it into physical vibrations to create sound waves
- electric current in the coil creates an electromagnetic field
- electromagnet is repelled by or attracted to permanent magnet
- causing coil to vibrate
- movement of coil causes cone to vibrate, vibration is transmitted to air in front of the cone
- amount of movement will determine frequency and amplitude of wave
5
Q
components of speaker
A
- cone
- coil of wire
- permanent magnet
- dust cap
6
Q
resistive touch screen
A
- consists of two charged plates
- pressure causes the plates to touch, completing circuit
- point of contact is registered
- coordinates are used to calculate position
7
Q
capacitive touch screen
A
- made from materials that store electric charge
- when touched, charge is transferred to the finger
- sensors at the screen corners detect the changes
- points of contact registered, coordinates are used to calculate position
8
Q
VR headset
A
- video is sent from a computer to the headset using a cable
- two feeds are sent to a LCD
- sometimes 2 screens are used
- lenses are used for focusing and reshaping the image
- most headsets use 60 to 120 frame rate and 110 degree field of view to make it realistic
- uses binaural sounds
9
Q
RAM (random access memory)
A
- volatile (temporary) memory
- data can be altered
- stores data in use
- is read/write
10
Q
ROM (read-only memory)
A
- non volatile memory (permanent)
- data cannot be changed
- stores boot up instructions
- is read only
11
Q
SRAM (static RAM)
A
- no refresh required hence uses less power and faster access time
- more expensive as more transistors
- stores each bit using flip flop (allows previously output value to be stored)
- less storage
- used in cache memory (storage for more frequently used data)
12
Q
DRAM (dynamic RAM)
A
- has to be refreshed hence slower access times and needs higher power
- uses single transistor and capacitor
- stores each bit as a charge
- less expensive as less transistors
- more storage
- used in main memory
13
Q
PROM (programmable ROM)
A
- initially empty
- can be programmed only once after created
- data cannot be erased or deleted
- chip becomes unusable
14
Q
EPROM (electronically programmable ROM)
A
- initially empty
- can be overwritten multiple times
- data can be erased/deleted
- EPROM can be erased using UV light
- must be entirely erased before writing
- chip has to be removed from device for reprogramming
15
Q
EEPROM (electrically erasable programmable ROM)
A
- initially empty
- erased by electrical signal to reprogram
- can update data without removing chip
- does not need to be entirely erased before writing
16
Q
buffer
A
buffer memory is temporary storage area in the RAM that stores data being transferred between two or more devices
17
Q
magnetic media
A
- surface coated with magnetic material
- magnetic properties are altered to represent 1s and 0s
- used by hard disks, magnetic tapes, floppy disks
18
Q
optical media
A
- surface coated with light sensitive material
- read/written by lasers
- CD’s use one spiral track
- used by DVD-RAM, CD-R, CD RW, CD ROM, bluray disc
19
Q
solid state media
A
- uses millions of tiny transistors
- where movement of electrons is controlled withina microchip
- has no moving parts
- used by memory sticks, MP3 players
20
Q
internal operation of HDD
A
- has one or more platters made of aluminium
- each surface of the platter is iron oxide which is capable of being magnetised
- platters are maintained on a central spindle
- disks are rotated at high speeds
- each surface of disk has read/write head mounted on an arm positioned just above the surface
- surface of platter is divided into concentric tracks and sectors
- one track in one sector is a basic unit of storage called block
- data is encoded as a magnetic pattern for each block
21
Q
internal operation of SSD
A
- no moving parts
- non volatile
- uses NAND and NOR gates
- SSD controller manages the components
- uses a grid of column and rows that has two transistors at each intersection
- one transitor is called floating gate
- second transistor is called control gate
- memory cells store voltages which can represent either a 0 or 1
- essentially the movement of electrons is controlled to read/write
- no overrwriting data/first erase then add
22
Q
flash memory
A
- most are NAND-based
- no moving parts
- one transitor is called floating gate
- second transistor is called control gate
- memory cells store voltages which can represent either a 0 or 1
- essentially the movement of electrons is controlled to read/write
- no overrwriting data/first erase then add
23
Q
optical disc
A
- drive motor is used to spin the disc
- tracking mechanism moves the laser assembly
- a lense focuses the laser onto the disc
- laser beam is shone onto disc to read/write
24
Q
DVD RW
A
- uses a single spiral track
- only allows write or read operation to occur as separate operations
- requires special packet reading/writing software
- in order to write new data, existing data on the disc must be completely erased
- performance degrades with time
- rotates at different speeds
- single sided: 4.7 GB capacity
25
Q
DVD RAM
A
- uses single concentric tracks
- allows simultaneous read/write operation
- no special read/write software required
- make use of sector to store data
- single or double sided: 4.7 GB per side
- disc rotates at constant speed
26
Q
general purpose computer
A
performs more than one specific task
27
Q
special purpose computer
A
performs one specific task
28
Q
embedded system
A
- microprocessor within a larger system that performs one specific task
- not easily updated by the owner (complex)
