Electronic Systems Flashcards
(131 cards)
1
Q
What is an electronic system?
A
A system made up of several parts that work together as a whole to carry out a function.
2
Q
What are the three main components of an electronic system?
A
Input, process, and output.
3
Q
What is an example of input in an electronic system?
A
Key on keyboard pressed.
4
Q
What does the CPU do in an electronic system?
A
Processes input data into output data.
5
Q
What is the output in an electronic system?
A
Monitor displays the processed data.
6
Q
What do systems diagrams show?
A
The input, process, and output stages of a system.
7
Q
How does the complexity of a system affect its diagram?
A
The more complex the system, the more blocks there are in the diagram.
8
Q
What is an electrical circuit?
A
A closed circuit that contains a sequence of components connected by wires to a source of power.
9
Q
What are circuit diagrams used for?
A
To show how a circuit works.
10
Q
What do symbols in circuit diagrams represent?
A
Electrical components.
11
Q
What pushes the current around the circuit?
A
Voltage from the power cell.
12
Q
In which direction does the electrical current flow in a circuit?
A
From positive to negative.
13
Q
What is a printed circuit board (PCB)?
A
A board that supports and connects electronic components.
14
Q
What do PCBs contain?
A
Copper tracks that link holes for electrical components.
15
Q
How are PCBs designed?
A
Specifically for each circuit.
16
Q
How are components attached to a PCB?
A
Directly onto the surface of a PCB through surface mounting.
17
Q
What are input devices?
A
Input devices trigger the system, sending an electrical signal to be processed.
18
Q
How are input devices triggered?
A
Some input devices are manually triggered, whereas others are triggered by movement or environmental changes.
19
Q
What is the function of switches?
A
Switches are used to complete or disconnect a circuit.
20
Q
How can a switch be operated?
A
A switch can be turned on (closed) to let current flow or turned off (open) to stop current flow.
21
Q
What forms do switches come in?
A
Switches come in many forms, including toggles, slides, pushes, and microswitches.
22
Q
What do Light-Dependent Resistors (LDRs) detect?
A
LDRs detect changes in light levels.
23
Q
How does resistance in LDRs change with light?
A
Resistance increases in the dark (limiting the current) and decreases in the light (increasing the current).
24
Q
Where are LDRs commonly used?
A
LDRs are often used in items such as street lights that come on automatically when it gets dark.
25
What do thermistors detect?
Thermistors are resistors that detect changes in temperature.
26
How does resistance in thermistors change with temperature?
Resistance decreases as temperature increases (increasing the current) and increases as temperature decreases (limiting the current).
27
Where are thermistors commonly used?
They are often used in air conditioning systems that turn on when the temperature rises.
28
What do pressure sensors detect?
Pressure sensors detect changes in pressure.
29
How does resistance in pressure sensors change?
Depending on the sensor's function, resistance either increases or decreases to allow more or less current to flow through.
30
Where are pressure sensors commonly used?
Sensors are often used in car tyres to notify drivers when air pressure drops below a certain level.
31
What are process devices?
Process devices process electronic signals from an input to determine an output action.
32
What role do integrated circuits (ICs) play in electronic systems?
ICs perform multiple tasks, reducing the number of components needed in a circuit.
33
What is a microcontroller?
A microcontroller is a type of IC programmed to perform specific tasks in various electronic devices.
34
What components are contained in a microcontroller?
It contains memory, programmable input/output peripherals, and a processor all on one chip.
35
How are programs written for microcontrollers?
Programs are written in a special programming language or can be created using flowcharts translated by software.
36
What are common programming languages for microcontrollers?
Common programming languages include embedded C, Python, BASIC, and Scratch.
37
What functions do microcontrollers serve in embedded systems?
Microcontrollers are often used as timers and counters to measure elapsed time or count external events.
38
What is the function of timers in microcontrollers?
Timers add a time delay by creating a pulse of voltage after a certain period to trigger an output.
## Footnote
An example includes a microwave timer.
39
What is the function of counters in microcontrollers?
Counters count the number of pulses of voltage created by an input device and display this as an output.
## Footnote
An example includes a pedometer, which counts each step a person takes.
40
How can circuits make decisions?
Circuits can be programmed to make decisions based on situations using logic gates.
41
What do NOT gates do?
NOT gates take one input and output the opposite value.
## Footnote
Example: If the emergency button is pressed (1), a treadmill will stop (0).
42
What do AND gates do?
AND gates take at least two inputs and output 1 if all inputs are 1; otherwise, the output is 0.
## Footnote
Example: If a burglar alarm is turned on (1) and the sensor detects movement (1), the alarm will sound (1).
43
What properties of materials are important for electronic systems?
The physical and working properties of different materials make them suited for use in different electronic and mechanical systems.
44
What must designers consider when selecting materials for domestic appliances?
Designers need to consider the function of appliances when selecting materials.
45
What materials are commonly used in electric blenders?
A mixture of glass, plastic, and sometimes stainless steel is often used.
46
How have developments in electronic systems improved domestic appliances?
Developments have made domestic appliances smarter, more energy efficient, stronger, and lighter.
47
What is an example of a cordless vacuum cleaner that uses new technologies?
The Dyson V10.
48
What is the purpose of Peripheral Interface Controllers (PIC)?
PICs allow devices to be programmed to perform multiple tasks and processes.
49
How have PICs improved appliances?
They have improved the functionality and efficiency of many appliances such as washing machines, microwave ovens, and central heating systems.
50
What material is commonly used for car bodies and why?
Aluminium is a popular choice because it is tough for protection yet lightweight for efficiency.
51
What are some advanced safety features in modern vehicles?
Features include Forward Collision Mitigation, Lane Departure Warning, and Adaptive Cruise Control.
52
How does Forward Collision Mitigation work?
Radar scans the road in front of the vehicle and alerts the driver if there is a sudden reduction in distance to the vehicle ahead.
53
What does the Lane Departure Warning system do?
A camera-based system monitors the vehicle's position in relation to lanes and alerts the driver if they unintentionally stray out of the lane.
54
How does Adaptive Cruise Control function?
Radar scans the road and the vehicle automatically adjusts its speed to maintain a safe distance from vehicles ahead.
55
What advancements have made vehicles more sustainable?
Developments in renewable energy resources, recycling, and new materials have led to more sustainable vehicles.
56
How do hybrid and electric cars compare to petrol and diesel cars in terms of emissions?
Hybrid and electric cars produce less CO2 emissions than petrol and diesel cars.
57
What improvements have lightweight and recycled materials brought to vehicles?
They have improved efficiency and end-of-life recovery.
58
What can be enhanced to perform new functions in electronic and mechanical systems?
The properties of materials.
59
What is a photoresist?
A material that loses its resistance due to a chemical change when exposed to light.
60
What is the purpose of photo-etching?
To transfer the design of a circuit onto PCBs.
61
What is the first step in the PCB photo-etching process?
The circuit is drawn on a mask, usually by using CAD software.
62
What happens to the parts of the photoresist board covered by the mask?
They will be protected from the UV light.
63
What occurs when the board is exposed to UV light?
A chemical change takes place.
64
What is done after the board is exposed to UV light?
The board is placed into an etching tank to remove excess copper and reveal the tracks.
65
What is anodising?
A process that makes metals such as aluminium more resistant and stronger through electrolysis.
66
What does anodising do to the surface of aluminium?
It causes the surface to oxidise, forming a dense and hard aluminium oxide layer.
67
What are the benefits of anodised aluminium?
It is hard-wearing, long-lasting, does not peel or chip, can be dyed, is a good electrical insulator, and is easily recyclable.
68
What are some uses of anodised aluminium?
Aircraft parts, electronics (such as smartphones), architectural features (such as cladding), exterior panels for spacecraft, vehicle parts (such as wheel covers), and cooking pans.
69
What are electronic components available in?
Electronic components are available in a wide range of shapes, sizes, and quantities.
70
What do current and voltage ratings indicate?
Current and voltage ratings indicate the levels at which components are designed to work.
71
What is voltage?
Voltage, measured in volts (V), is the potential difference between two points in an electric circuit.
72
What is current?
Current, measured in amperes (amps or A), is a flow of electrical charge in a circuit.
73
What happens if the voltage or current is too low?
If the voltage or current is too low, the component may not work effectively (e.g. a buzzer may be too quiet).
74
What happens if the voltage or current is too high?
If the voltage or current is too high, the component could fail (e.g. a bulb could blow).
75
What is an example of voltage ratings in appliances?
Mains power supplies typically have a power supply of 230 V. Using a component such as a small electronic buzzer, with a rating of 1.5 V, would damage the buzzer.
## Footnote
Mains power supplies are ideal for appliances such as kettles, which have a voltage rating very close to the power supply.
76
What are standard components in a circuit?
There are various standard components available for use within a circuit.
77
What is a Dual In-Line (DIL) IC Package?
A DIL is an IC packaged inside a block of black plastic with two parallel rows of tiny pins.
78
What is the purpose of an integrated circuit (IC)?
Integrated circuits (ICs) can perform multiple tasks, thus reducing the number of components needed in a circuit.
79
How is a DIL attached to a circuit?
A DIL can be attached to the circuit by soldering, but an IC socket is often used to avoid heat damage.
80
What is the benefit of using an IC socket?
An IC socket allows the DIL to be changed easily for repairs.
81
What is a microcontroller?
A microcontroller is a type of IC used in various electronic devices to perform specific tasks. It contains memory, programmable input/output peripherals, and a processor, and runs at a voltage of between 3 and 5.5 V.
82
What are Programmable Intelligent Computers (PICs)?
PICs are a type of microcontroller available with a range of memory storage capacities, including flash memory, allowing them to be reprogrammed repeatedly.
83
What are the advantages of PICs?
PICs are low-cost, easy to reprogram, and can perform multiple tasks, making them ideal for diverse applications such as video games and household appliances.
84
What is the purpose of resistors?
Resistors reduce or limit the current in a circuit to prevent damage to components.
85
How is resistance measured?
Resistance is measured in ohms (Ω).
86
What are the types of resistor bands?
Four-band resistors have two resistance bands, one multiplier band, and one tolerance band. Five-band resistors have three resistance bands, one multiplier band, and one tolerance band.
87
What is an example of a four-band resistor?
A 560kΩ resistor with 10% tolerance.
## Footnote
Example of a four-band resistor.
88
What is an example of a five-band resistor?
A 237Ω resistor with 1% tolerance.
## Footnote
Example of a five-band resistor.
89
What colors represent the digits in resistor coding?
The colors are: Black (0), Brown (1), Red (2), Orange (3), Yellow (4), Green (5), Blue (6), Violet (7), Grey (8), White (9).
90
What is the E12 resistor series?
The E12 resistor series consists of 12 different values: 1.0, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6, 6.8, and 8.2Ω, each of which can be multiplied to the power of 10.
91
What is the tolerance of E12 resistors?
Each value in the E12 series has a tolerance of 10%.
92
What is the tolerance of three-band resistors?
Three-band resistors have no tolerance band.
93
What is the tolerance of six-band resistors?
Six-band resistors have an additional band that specifies the temperature coefficient but have a tolerance of +20%.
94
What are the methods used to cut components in electronic systems?
Components can be cut using laser cutters, guillotines, or utility knives.
95
What materials can laser cutters cut?
Laser cutters can cut a wide range of materials including acrylic, paper, wood, and metal (e.g. stainless steel).
96
How does a laser cutter work?
A laser beam is directed through a lens that focuses it down to a very small high-intensity beam, which burns through the material for accurate cuts.
97
What are the advantages of using laser cutters?
Laser cutters have a very high degree of accuracy, allow for complex designs with CAD, and do not wear out like blades.
98
What are the disadvantages of laser cutting?
Laser cutting consumes a lot of energy, making it expensive, and is not suitable for all materials (e.g. PVC releases toxic chlorine gas when cut).
99
What is the purpose of drilling in PCBs?
Drills are used to make small holes in PCBs for inserting and soldering component pins or wires.
100
What size are the holes typically drilled in PCBs?
The holes are usually no more than 1.5 mm in diameter.
101
What tools are often used for drilling PCBs?
Specialist drill bits and a drill press mounted on a stand are often used for improved accuracy.
102
What is an alternative method to drill small holes in PCBs?
Laser drilling is another option, providing the most precise method but is also the costliest.
103
What can be used to enhance grip when using a hand drill?
Specialist tools such as pin chucks are often used.
104
What is soldering?
Soldering involves joining metal with a filler (usually an alloy of lead and tin) that has a relatively low melting point.
105
How is soldering performed?
The filler is melted with a soldering iron and applied to the parts that are to be joined.
106
What is the purpose of soldering?
Soldering is used to attach components to circuit boards.
107
What is a good solder joint shape?
A good joint has a volcano shape and shiny solder.
108
What indicates a bad solder joint?
A bad joint is indicated by dull solder.
109
How are components soldered into place?
Components are soldered into place by attaching them, their pins or wires to copper tracks or wires on the PCB.
110
What shape should solder ideally have?
The solder should be 'volcano-shaped.'
111
What is necessary for achieving a good solder joint?
Both the component leg and the wire or copper track must be hot enough.
112
What happens to protruding wires after soldering?
Protruding wires are then snipped away after soldering.
113
What are the properties of solder?
Solder is an electrical conductor and provides a low-resistance path for current to flow from one component to another.
114
What does solder wire contain?
Solder wire contains flux, which prevents the metals from oxidising.
115
What is flow soldering?
Flow (or 'wave') soldering is used in large production runs to connect components to PCBs.
116
How does flow soldering work?
The circuit board is passed over a pan of molten solder, and a pump causes an upwelling of solder that looks like a wave.
117
What is crucial during flow soldering?
It is vitally important that components are assembled correctly and that any parts that do not need soldering are covered by a protective film.
118
What is pick and place assembly?
Components can be placed on PCBs by hand or by using a computer numerical control (CNC) pick and place machine.
119
How were components placed on PCBs before pick and place machines?
Before pick and place machines, all placement was done manually, even for complex PCBs.
120
What are the advantages of pick and place machines?
Pick and place machines offer a far more efficient and accurate method of populating PCBs ready for soldering.
121
How do pick and place machines work?
Components are picked off reels or tapes with suction cups, rotated to the correct angle, and placed on the PCB.
122
What is the cost-benefit of pick and place machines?
Although costly to set up, pick and place machines are ideal for producing complex PCBs quickly and accurately on an industrial scale, resulting in less waste due to error.
123
What is PCB lacquering?
PCB lacquering is the application of a protective coating to the surface of a PCB to prevent damage from moisture, dust, extreme temperatures, and chemicals.
124
What does PCB lacquering create?
It creates a thin polymer film that acts as a protective barrier.
125
What are the benefits of PCB lacquering?
It improves the lifespan of the PCB and makes the product more reliable.
126
How does PCB lacquer appear under UV light?
It appears as a green-white color, making it easy to inspect during quality control.
127
What is lubrication?
Lubrication is the process of reducing friction using oils, greases, fluids, or gases.
128
What is friction?
Friction is the resistance caused when two surfaces rub together.
129
What are some uses of grease?
Grease is used in hinges and bearings.
130
What is graphite used for?
Graphite is a dry lubricant used in locks and fasteners.
131
Why is lubrication important for gears?
Lubrication allows gears to move smoothly, preventing wear and inefficiency caused by friction.
