Chapter 3

Question 1

Memory cache

Answer 1

high speed memory external to processor

which stores data which the processor will need again.

Question 2

Random access memory (RAM)

Answer 2

primary memory unit

that can be written to and read from.

Question 3

Read-only memory (ROM)

Answer 3

primary memory unit that

can only be read from.

Question 4

qHard disk drive (HDD)

Answer 4

type of magnetic storage device

that uses spinning disks.

Question 5

Solid state drive (SSD)

Answer 5

storage media with no moving

parts that relies on movement of electrons.

Question 6

Flash memory

Answer 6

a type of EEPROM, particularly suited
to use in drives such as SSDs, memory cards and
memory sticks.

Question 7

Dynamic RAM (DRAM)

Answer 7

type of RAM chip that needs

to be constantly refreshed.

Question 8

Static RAM (SRAM)

Answer 8

type of RAM chip that uses

flip-flops and does not need refreshing.

Question 9

Refreshed

Answer 9

requirement to charge a component to

retain its electronic state.

Question 10

Latency

Answer 10

the lag in a system; for example, the time to
find a track on a hard disk, which depends on the time
taken for the disk to rotate around to its read-write head.

Question 11

Fragmented

Answer 11

storage of data in non-consecutive sectors;

for example, due to editing and deletion of old data.

Question 12

Programmable ROM (PROM)

Answer 12

type of ROM chip that

can be programmed once.

Question 13

Erasable PROM (EPROM)

Answer 13

type of ROM that can be

programmed more than once using ultraviolet (UV) light.

Question 14

Inkjet printers

Answer 14

made up of
- a print head consisting of nozzles that spray droplets of ink onto the paper
to form characters
- an ink cartridge or cartridges; either one cartridge for each colour (blue,
yellow and magenta) and a black cartridge, or one single cartridge
containing all three colours and black (note: some systems use six colours)
- a stepper motor and belt which moves the print head assembly across the
page from side to side
- a paper feed which automatically feeds the printer with pages as they are
required.

Question 15

Thermal bubble

Answer 15

tiny resistors create localised heat which makes the ink
vaporise. This causes the ink to form a tiny bubble, as the bubble expands
some of the ink is ejected from the print head onto the paper. When the
bubble collapses, a small vacuum is created which allows fresh ink to
be drawn into the print head. This continues until the printing cycle is
completed.

Question 16

Piezoelectric

Answer 16

a crystal is located at the back of the ink reservoir for each
nozzle. The crystal is given a tiny electric charge which makes it vibrate. This
vibration forces ink to be ejected onto the paper and at the same time more ink
is drawn in for further printing.

Question 17

Laser printers

Answer 17

Laser printers use dry powder ink rather than liquid ink and make use of the
properties of static electricity to produce the text and images. Unlike inkjet
printers, for example, laser printers print the whole page in one go. Colour laser
printers use four toner cartridges – blue, cyan, magenta and black. Although
the actual technology is different to monochrome printers, the printing method
is similar, but colour dots are used to build up the text and images.

Question 18

3D printers

Answer 18

e used to produce working, solid objects. They are primarily based
on inkjet and laser printer technology. The solid object is built up layer by layer
using materials such as powdered resin, powdered metal, paper or ceramic.

Question 19

Speakers

Answer 19

-The digital data is first passed through a digital to analogue converter (DAC)
where it is converted into an electric current.
- This is then passed through an amplifier (since the current generated
by the DAC will be small) to create a current large enough to drive a
loudspeaker.
- This electric current is then fed to a loudspeaker where it is converted into
sound.

Question 20

Microphones

Answer 20

-When sound is created, it causes the air to vibrate.
- When a diaphragm in the microphone picks up the air vibrations, the
diaphragm also begins to vibrate.
- A copper coil is wrapped around a permanent magnet and the coil is
connected to the diaphragm using a cone. As the diaphragm vibrates, the
cone moves in and out causing the copper coil to move backwards and
forwards.
- This forwards and backwards motion causes the magnetic field around the
permanent magnet to be disturbed, inducing an electric current.
- The electric current is then either amplified or sent to a recording device.
The electric current is analogue in nature.

Question 21

Digital to analogue converter (DAC)

Answer 21

needed to
convert digital data into electric currents that can drive
motors, actuators and relays, for example.

Question 22

Analogue to digital converter (ADC)

Answer 22

needed to
convert analogue data (read from sensors, for example)
into a form understood by a computer.

Question 23

Touch screen

Answer 23

screen on which the touch of a finger or
stylus allows selection or manipulation of a screen image;
they usually use capacitive or resistive technology.

Question 24

Capacitive

Answer 24

type of touch screen technology based
on glass layers forming a capacitor, where fingers
touching the screen cause a change in the electric field.

Question 25

Virtual reality headset

Answer 25

apparatus worn on the head
that covers the eyes like a pair of goggles. It gives the
user the ‘feeling of being there’ by immersing them
totally in the virtual reality experience.

Question 26

Sensor

Answer 26

input device that reads physical data from its

surroundings.

Question 27

Organic LED (OLED)

Answer 27

uses movement of electrons
between cathode and anode to produce an on-screen
image. It generates its own light so no back lighting
required.

Question 28

Resistive

Answer 28

type of touch screen technology. When
a finger touches the screen, the glass layer touches
the plastic layer, completing the circuit and causing a
current to flow at that point.

Question 29

Logic gates

Answer 29

electronic circuits which rely on
‘on/off’ logic. The most common ones are NOT, AND,
OR, NAND, NOR and XOR.

Question 30

Truth table

Answer 30

a method of checking the output from
a logic circuit. They use all the possible binary input
combinations depending on the number of inputs;
for example, two inputs have 22 (4) possible binary
combinations, three inputs will have 23 (8) possible
binary combinations, and so on.