Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Computer science > Unit 4 - Software > Flashcards

Unit 4 - Software Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What is an input device?

A

Input devices transfer data form the source in the outside world to the computer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are some examples of input devices?

A
  • Keyboards​
  • Mice​
  • Digital cameras​
  • Games controllers​
  • Microphones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How do computer systems work?

A
  • Input devices putting data into the system​
  • The data is processed​
  • The processed data may then be saved using primary or secondary storage​
  • Output devices send data from the computer to the user
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How is a keyboard made?

A

A key is made from plastic and has a small peg underneath which fits exactly into a hole in the keyboard when it is pressed ​
A small piece of rubber under the key makes it bounce back up so that it is ready to be pressed again

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does a keyboard work?

A

When a key is pressed, the small bar under the key pushes through a small hole and makes contact with a conducting membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is an optical mouse?

A

A computer mouse is used for pointing and selecting areas on a display

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does an optical mouse work?

A

An optical mouse shines light from a red LED onto a surface​

A sensor takes repeated images of the surface and compare how these change when the mouse is moved

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does a microphone work?

A

When sound reaches the microphone, the diaphragm vibrates backwards and forwards​

This causes the coil to vibrate which then changes the ​magnetic field produced by the magnet​

Changes in current are detected and a signal is output​

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is analogue data converted to digital data?

A

The output from the microphone is analogue ​

This analogue signal needs to be converted into a digital signal so the computer can understand the data​

An analogue to digital convertor (ADC) carries out ​
the conversion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the 3 different technologies used in touchscreen?

A

Resistive​
Capacitive​
Infra-red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a resistive touchscreen made off?

A

Resistive touchscreens are made up of a layer of conductive polyester and a layer of conductive glass​

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do resistive touchscreens work?

A
  • The two layers are separated by an insulating membrane​
  • When the screen is gently pressed by a finger, the two conducting layers make contact and complete a circuit​
  • The position where the screen is touched is calculated ​
    by a microprocessor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are capacitive touchscreens made of?

A

Capacitive touchscreens are made up of glass layers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do capacitive touchscreens?

A
  • The bottom surface of the upper layer and top surface of the bottom layer are coated in perpendicular lines of transparent conductive material (Indium Tin Oxide) forming a grid​
  • The screen behaves like a capacitor, storing electrical energy​
  • The screen can be touched in more than one place at a time
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does a capacitive screen detect a touch?

A

When the screen is touched by a finger, there is a change in the electric field at that position​

The position where the field changes is calculated by a microprocessor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the advantages of using capacitive touchscreens?

A
  • Capacitive screen have a smooth surface​
  • They are very easy to press​
  • They are highly accurate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the disadvantages of using capacitive touchscreens?

A

Capacitive screens don’t work if the ​user is wearing gloves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the disadvantages of using capacitive touchscreens?

A

Capacitive screens don’t work if the ​user is wearing gloves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How are Infra-red touchscreens made?

A

LEDs shine infra-red light across the screen from the edges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How do infra-red touchscreens work?

A
  • The infra-red rays form a grid across the screen​
  • When the screen is touched by a finger, the infra-red beam is interrupted​
  • A microprocessor calculates the coordinates of where the screen was touched
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are two common types of barcode systems?

A

Universal Product Code version ‘A’​
(UPC-A)​
- Used in retail and warehousing​

Code 128​
- Used in transport and ​
shipment tracking

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How does a UPC-A system work?

A

This uses long guard bars to show the start and end of the barcode and also central guard bars to distinguish left uniquely from right. UPC-A uses seven bar elements to form four alternating dark and light bars of varying thicknesses to represent each data item between the guard bars

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How does a UPC-A system work?

A

This uses long guard bars to show the start and end of the barcode and also central guard bars to distinguish left uniquely from right. UPC-A uses seven bar elements to form four alternating dark and light bars of varying thicknesses to represent each data item between the guard bars

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How do you read UPC-A retail barcodes?

A

Visually, a grouping of two or more adjacent bars appear as a single wide bar​

Right hand codes are the inverse of left hand codes​

Left hand codes all have an odd number of black bars. Right hand codes all have an even number​

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Why are barcodes used?

A
  • It is faster to scan products than enter a price into a till​
  • Previously, many shops would close to carry out a stock control. This is no longer necessary​
  • Barcodes reveal a number that identifies each product. This allows a shop to determine how many items are sold which saves the need for shop workers to manually check ​
    stock levels​
  • By having barcodes on products, prices can be changed without needing to update the price on each product​
  • Customers are able to scan their own items, resulting in a reduced need to till operators
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is a QR code?

A

QR codes are 2D barcodes and can be read by smartphones or tablets sending you to a hyperlink.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What do QR codes contain?

A
  • link to websites (hyperlinks)

- information

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What can QR codes be used for (name 3)?

A
  • Tracking packages​
  • Restaurant coupons ​
    and menus​
  • Mobile concert tickets​
  • Estate agency boards​
  • Business cards​
  • Tourist information​
  • Advertising posters​
  • Self service tills
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are 2D scanners used for?

A

These are used to convert documents or ​photographs into a digital format.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How do 2D scanners work?

A
  • A scanner head contains a bright light and lens​
  • The focused image then falls on to a ​light-sensitive sheet made up of thousands of ​pixels which record the light intensity or ​
    colour falling on each pixel​
  • This information is now ​
    stored as an image in ​
    the computer’s memory
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are 2D scanners often embedded in?

A
  • Multi-function printers​

- Photocopiers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

How do 3D scanners work?

A
  • 3D scanners use a laser to scan across an object​
  • Two sensors detect the distance from ​
    the laser to the object​
  • This creates a ‘point cloud’ which is then processed ​
    into a 3D representation of ​
    the object
33
Q

What is an example of 3D scanners in use?

A
  • 3D scanners are used in both ​industrial and medical fields​
  • Many 3D scanners rely on a ​technology called Tomography ​which involves taking ​images in very thin ​slices less than ​0.1 mm thick
34
Q

How does a digital camera work

A
  • Digital cameras focus light onto a CCD sensor (Charge-Coupled Device)​
  • The CCD breaks up the image into a grid of pixels​
  • The shutter opens to let light onto a CCD sensor at the back of the lens​
  • A sensor measures the light ​intensity of each pixel​
  • Once processed, the ​
    information is then stored ​
    as an image in the ​
    camera’s memory
35
Q

What are some physical properties that can be measured?

A
  • Sound intensity​
  • Acceleration​
  • Pressure​
  • Light intensity​
  • Infra-red (heat) intensity​
  • Magnetic field​
  • Moisture​
  • pH​
  • Distance
36
Q

What is the definition of sensor?

A

A hardware device that can take measurement of physical properties, such as temperature or pressure, from real world surroundings. These measurements are usually a representation of the actual property being measured.

37
Q

What is an analogue measurement?

A

Analogue means that data has no discrete ​value and the data changes smoothly rather ​than in exact jumps​

38
Q

What applications can temperature sensors be used for?

A 
- a temperature sensor is used to monitor the temperature of the cooling system​. If the temperature gets too hot, a fan can be turned on or the driver can be alerted to the problem. Cars may also monitor the temperature ​inside the car, applying heaters or ​
air conditioning as appropriate
- Automatic washing machines
- central heating systems
- automatic greenhouses
- cookers
39
Q

What is a temperature sensor?

A

It is a device to measure temperature, can be air temperature, liquid temperature or solid matter.

40
Q

What applications can pressure sensors be used for?

A

Pressure sensors are now required inside car tyres on all new cars​
- These are located behind the tyre valve used to ​
inflate the tyre​
- They constantly transmit the pressure​ to the engine control unit (ECU)​
- If the ECU detects the pressure ​is too low, such as with a slow ​puncture, it will display a ​warning to the driver
- burglar alarm systems
- washing machines
- robotics
- environmental monitoring

41
Q

What is a pressure sensor?

A

Pressure sensors can also be used to indirectly measure other variables such as fluid/gas flow, speed, water level, and altitude.

42
Q

What applications can proximity sensors be used for?

A

Car proximity sensors make use of ultrasound​
- A sound wave is transmitted from the car​
- An echo is produced from a nearby object​
- The time it takes for the echo to be received allows the distance to be calculated​
- These sensors are helpful ​
to drivers when reversing ​
as they warn of objects ​
that they may reverse into

43
Q

What is a proximity sensor?

A

Proximity sensors are able to detect objects without touching them

44
Q

What are sensors used for?

A

Used for monitoring and controlling applications.

45
Q

What does a accelerometer do?

A
  • An accelerometer measures the acceleration of an object and the direction it is moving in​
  • In smartphones this is used to determine whether the phone is orientated in landscape or portrait​
  • Some game controllers also use 3-axis accelerometers​
    to determine the direction ​
    that the controller is moving​
46
Q

What applications is a moisture sensor used for?

A
  • control or monitor the dampness of soil in a greenhouse​
  • monitor the dampness of clothes as they pass over a sensor in a tumble dryer​
  • measure water content in a lawn for an automatic watering system
47
Q

What applications can a humidity sensor be used for?

A
  • monitor the humidity in the air of a greenhouse​
  • control a dehumidifier in a home​
  • monitor the humidity in a factory making microchips
48
Q

What applications can a level sensor be used for?

A
  • monitor the amount of fuel in a car​
  • monitoring the amount of oil in a car’s engine​
  • measuring the height of flour in a food processing plant
49
Q

What applications can light sensors be used for?

A
  • switch street lighting on at dusk and switch street lighting off at dawn​
  • automatically switch a car’s headlights on when it gets dark​
  • to close or open the window blinds in a greenhouse to maintain light levels
50
Q

What applications can infra-red be used for?

A
  • turn on a car’s windscreen wipers automatically when it starts to rain​
  • detection of intruders in a burglar alarm system​
  • count the number of people entering or leaving a supermarket
51
Q

What applications can a flow sensor be used for?

A
  • measure how quickly a chemical is moving through a pipe in a chemical plant​
  • measure the speed of water in water pipes​
  • monitor the flow of water in a river
52
Q

What applications can an acoustic sensor be used for?

A
  • pick up noise levels (e.g. footsteps) in a burglar alarm system​
  • detect the noise of liquids dripping from a pipe in an oil refinery​
  • monitor the sound levels in a car factory
53
Q

What applications can a gas sensor be used for?

A
  • monitor CO2/O2 levels in a river​
  • monitor CO2/CO/O2 levels in the air beside a road​
  • check for the carbon monoxide levels in a car exhaust system
54
Q

What applications can a pH sensor be used for?

A
  • monitor or control the acidity levels in a chemical process​
  • measurement of pollution levels in a river​
  • check acidity levels in the soil in an agricultural field
55
Q

What applications can a magnetic field sensor be used for?

A
  • used in smart phones so they know which direction it is pointing​
  • used in the motors of CD players​
  • used in vehicle anti-lock braking systems
56
Q

What is a moisture sensor?

A

Measures the water content

57
Q

What is a humidity sensor?

A

Humidity sensors are used to measure and monitor the amount of water present in the surrounding air.

58
Q

What is a level sensor?

A

A level sensor is a device for determining the level or amount of fluids, liquids or other substances that flow in an open or closed system.

59
Q

What is an infra-red sensor?

A

Infrared sensors are also capable of measuring the heat being emitted by an object and detecting motion.

60
Q

What is a flow sensor?

A

Flow sensors are devices used for measuring the flow rate or quantity of a moving liquid or gas

61
Q

What is an acoustic sensor?

A

Detects sound

62
Q

What is a gas sensor?

A

A gas sensor is a device that senses the atmosphere’s presence or concentration of gases.

63
Q

What is a pH sensor?

A

A pH sensor helps to measure the acidity or alkalinity of the water with a value between 0-14.

64
Q

What is a magnetic field sensor?

A

Magnetic field sensors are used to measure magnetic flux and/or the strength and direction of a magnetic field.

65
Q

What 3 sensors are used in a security system?

A
  • The pressure sensors monitor an intruder stepping on the floor next to the windows, doors or on the floor next to valuable paintings​
  • The acoustic sensors pick up the sound of breaking glass or footsteps on the floor​
  • The infra-red sensors pick up movement in the rooms but also any changes in heat (e.g. heat radiation from an intruder)
66
Q

How does the sensor give infomation?

A

The microprocessor will have access to pre-set values for all sensors.
The microprocessor will sample each sensor at a given frequency (e.g. every second)
If any of the sensor readings exceed the pre-set values, then the microprocessor sends a signal to warn the user (this could be a screen output, a siren, a flashing light …. or all three)
Monitoring continues until the user keys in a PIN/passcode to deactivate the system

67
Q

How is analogue converted into digital data

A

Data is converted into ​digital form using an ​Analogue to Digital ​Converter (ADC) and is ​sent to a microprocessor

68
Q

How would a system work to keep the ​pH constant would work?

A

The pH sensor sends analogue data to a microprocessor about the pH currently being output​

The system is programmed to be at a certain pH value, e.g. 7​

If the pH goes below this value, it is acidic, so a valve will be opened so that a base (alkali) is added​

If the pH goes above this value, it is alkali, so a valve will be opened to add an acid

69
Q

What are some examples of output devices?

A
  • Displays and projectors​
  • Printers​
  • Speakers​
  • Actuators
70
Q

What are output devices?

A

Output devices transfer data produced by a computer and turn it into a human-readable form

71
Q

What are the 2 main types of inkjet printers?

A
  • Thermal bubble​

- Piezoelectric crystal

72
Q

Explain how thermal bubble works?

A
  • Behind hundreds of print nozzles there are tiny resistors that create heat​
  • The heat causes the ​ink to vaporise and ​form tiny bubbles​
  • As each bubble ​expands, ink is ​ejected onto the paper​
  • As it cools, the bubble collapses and draws in fresh ink ​and the process continues until the page is printed
73
Q

Explain how Piezoelectric crystal printing works?

A
  • A small piezoelectric crystal is located at the rear of each ink reservoir of each nozzle​
  • When the crystal receives a small electric current, it begins to vibrate in and out​
  • As it vibrates inwards, ink is ejected onto the paper​
  • As it vibrates outwards again, new ink is drawn in to replace it​
74
Q

What are the benefits and drawbacks of thermal bubble?

A

BENEFITS:

  • Less expensive technology than piezoelectric​
  • Possible to use more print nozzles​

DRAWBACKS

  • Produces larger droplet sizes​
  • Only certain inks can be used because of the high heat​
  • More maintenance is needed because of the high
  • temperatures involved​
75
Q

What are the benefits and drawbacks of piezoelectric crystal?

A

BENEFITS:

  • Very precise ink drop sizes can be produced​
  • Wide range of ink types can be used​
  • Can produce very small ink droplets​
  • Can run for longer since less heat is generated​

DRAWBACKS:

  • More expensive technology than thermal bubble​
  • Can use fewer print heads​

​

76
Q

How do laser printers work?

A

Laser printers use dry toner rather than liquid ink ​
as in inkjet printers​
- The laser will scan across the print drum ​to apply an electrostatic charge to it​

  • The drum will pick up a charged ​powder known as toner​
  • The toner will stick to the paper​
  • A heated fuser then makes ​sure the toner can’t be rubbed ​off the page​
  • Pages are printed faster ​than inkjet printers​
77
Q

What is a 3D printer?

A

3D printers can print using plastic filament, powdered ​resin, ceramic or metal ​powder, or paper​

Intricate objects can ​be printed, including ​hollow areas.

78
Q

What are the uses of 3D printers?

A

3D printers produce physical objects​
These may be custom made parts or aesthetic objects​

Recently, 3D printers have ​also begin to be used for:​

  • Food printing​
  • House building​
  • Replacement parts​
  • Medical devices​

Computer science (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions