Subject content

Unit 1: Electrical Safety

Dangers of electricity

Dangers of Electricity

Candidates should know the effects on the human body of an electric current.

First Aid

First Aid

Candidates need to be able to outline the procedures for dealing with a casualty who has suffered an electric shock or burn.

Prevention of accidents with electricity

Prevention of accidents with electricity

Candidates should be able to:

  • Explain why an individual should not work without proper supervision and explain why all persons should know how to summon help in an emergency.
  • Carry out a risk assessment of their planned activity while considering how the environment affects the dangers of electricity.
  • Explain why portable appliances should be regularly tested.
  • Explain why capacitors may hold a lethal charge even though the equipment is isolated.
  • Explain why components may become hot.

Electrical safety devices

Electrical safety devices

Candidates should know:

  • the purpose and limitations of circuit breakers (thermal, fuse, magnetic)
  • how to calculate the appropriate value for the circuit breaker
  • how to wire a three-pin mains plug
  • at a transformer can be used to obtain a safe low voltage from the mains supply.

Unit 2: System design

System diagrams

System design

Electronic systems are composed of one or more subsystems.

Electronics engineers design complex systems composed of combinations of subsystems in order to solve problems.

System diagrams

Candidates should know:

  • that a simple system has an input, a process and an output
  • that using arrows between subsystems represents the flow of information rather than wiring.

Candidates should be able to analyse and design system diagrams as an aid to the understanding and representation of complex systems.

System sequence

System Sequence

Candidates should be able to construct and interpret flowchart diagrams which describe a sequence of events, using the following symbols only.

flowchart symbols

System inputs and outputs

System inputs and outputs

Candidates should be able to:

  • Describe the functions and uses of common input and output transducers.

  • recall that a signal is an electrical current or voltage representing information.

  • explain that electrical noise is an unwanted signal.
  • describe how electrical noise may be reduced.

System processors

System proccessors

Candidates should be aware of the following basic processes:

  • counting
  • timing
  • amplifying
  • logic
  • memory
  • ADC and DAC.

Unit 3: Information system processing

Digital subsystems

Candidates need to be aware that many input devices produce analogue signals and that audio systems usually contain audio amplifiers which are analogue systems requiring an analogue input and producing an analogue output. Candidates should investigate these subsystems in a practical context and there is the opportunity for them to use protoboard in preparation for their controlled assessment (practical project). Candidates should be aware that analogue and digital information need to be processed in different systems and that analogue information can be converted to digital information and vice versa.

Digital subsystems

Candidates should be able to explain the use of logic gates, flip-flops, counters and timers.

Combinational logic

Combinational logic

Candidates should be able to recall that:

  • in a digital system a voltage signal is either at a high level or low level and that these
    states are represented by 1 or 0 respectively
  • a logic gate is a device with one output and several inputs and the output is either at a high level or a low level depending on the combination of input signals.

Candidates should be able to:

  • demonstrate knowledge of AND, OR, NOT, NAND and NOR gates using the following symbols only

GCSE-page-8-Electronics-combinational-logic

  • construct and interpret truth tables for each of the above gates
  • use truth tables to determine the output of a combination of up to four of the above gates

e.g GCSE-page-8-Electronics-combinational-logic-number2

  • solve system problems, stated in words, using combinations of logic gates
  • solve system problems which may have up to three separate inputs.

Sequential logic

Sequential logic

 Candidates should be able to:

  • describe the operation and use of a 4013 type D-type flip-flop
  • explain the function of a D-type flip-flop as a data latch and as a frequency divider
  • recognise and draw simple timing diagrams for frequency dividers
  • describe the operation and use of a 4017 type counter IC
  • recognise and draw simple timing diagrams for 4017 type counters.

Astable and monostable generators

Astable and monostable generators

Candidates should be able to:

  • use and explain the application of a 555 integrated circuit in monostable and astable mode
  • use the formulae for the 555 integrated circuit which relates time period to circuit values in both monostable and astable modes.

Candidates need to be able to use and manipulate the formula for time period.

In monostable mode, time period T = 1.1 R x C

Monostable and astable generators

Analogue signal processors

Analogue signal processors

Candidates should be able to:

  • recall that analogue signals are those that vary with time, taking on all values between a
    maximum and a minimum
  • recall that analogue circuits are those which handle analogue signals.

Analogue subsystems

Analogue subsytems

Candidate should be aware of:

  • the use of the low power audio amplifier ICs
  • the use of the op-amp comparators with various sensors.

The audio amplifier

The audio amplifier

Candidates should be able to:

  • use the relationship

  • know that bandwidth is the range of frequencies over which the amplifier produces at least half of its rated output power
  • describe the operation and use of an audio amplifier IC (low power types only such as LM380, LM386 or TBA820).

The op-amp comparator

The op-amp comparator

Candidates should know that an operational amplifier has a very large input resistance, a low output resistance, a very large voltage gain and saturates at the supply voltages.

Candidates should be able to explain the function and use of the circuit below as a voltage comparator using a single rail supply. A voltage comparator can be used as a one-bit analogue to digital converter.

[insert diagram]

Unit 4: The science of components

Basic principles

The science of components

This unit considers the components that candidates are likely to encounter in their course and examines the underlying scientific concepts.

Basic principles

Candidates should be able to draw and interpret circuits using standardsymbols for components (see Appendix G) in this specification.


Candidates should know that:

  • the unit of voltage is the volt, ( V )
  • the unit of current is the amp, (A)
  • The unit of resistance is the ohm, (Ω).

Candidates should be able to use the facts that:

  • the sum of the voltages in a series circuit is equal to the voltage across the whole circuit
  • there is the same voltage across each component in a parallel circuit
  • the current in a series circuit is the same everywhere in the circuit
  • the sum of the currents entering a junction is the same as the sum of currents leaving the junction
  • there may be a current passing through a component only when there is a voltage across it
  • the resistance of a component or circuit is given by:

Candidates should be able to:

  • calculate the effective resistance of up to four resistors in series
  • calculate the effective resistance of two resistors in parallel
  • explain the use and applications of a voltage divider*   calculate the output voltage of a voltage divider assuming a negligible load current
  • explain the use and application of a pull up/pull down resistor. Candidates should be able to:
  • use the following formula to calculate power

and know that the unit of power is the watt, (W). Candidates should know, and be able to use thefact that:

  • the unit of frequency is hertz, (Hz)
  • the unit of capacitance is the farad, (F). Candidates should be able to:*   use the relationship peak value = 1.4 x rms value for a sine wave
  • sketch a voltage-time or current-time graph for a sine wave, indicating peak and period values
  • use the relationship

Passive components

Passive components

 Candidates should be able to:

  • select components with appropriate power or current or voltage ratings for a given application (Constructional details of the components specified in the specification will not be examined.)
  • interpret the markings on a resistor using the colour code and BS1852 code to determine its value and tolerance
  • select an appropriate preferred value from the E24 series of resistors
  • interpret the markings on a capacitor (excluding colour code), to determine the capacitance, voltage rating, tolerance and polarity (where necessary)
  • interpret the markings on a surface mounted resistor or a capacitor using the BS code
  • select an appropriate component from a given list of alternatives
  • explain the differences in application and use of polarised and non-polarised capacitors
  • select and describe the use of an appropriate switch, e.g. reed switch, microswitch, toggle
    switch, tilt switch etc.
  • recognise and recall circuits which make use of the components given above.

Candidates should be able to state and use the fact that:

  • a diode conducts in one direction only
  • the forward voltage drop of a silicon diode is 0.7 V. Candidates should be able to:
  • explain the meaning of the terms forward-bias and reverse-bias
  • explain the use of diodes in rectification as half-wave and bridge full-wave rectifiers
  • explain the use of a diode connected across a relay coil or motor as a device to protect the semiconductor driver from damage
  • use a light emitting diode (LED) and calculate the value of an appropriate series resistor for the LED
  • use the fact that a light-dependent resistor (LDR) has a very high resistance in the dark and that its resistance decreases as the illumination increases
  • use the fact that a thermistor (ntc type) has a resistance that decreases as the temperature increases
  • recognise and recall circuits which make use of the components given above.

Active components

Active components


Candidates should know that:

  • a bipolar transistor is a 3-lead device, the lead names being emitter, collector and base. (Examination questions will be restricted to npn silicon transistors.)
  • a MOSFET (Metal Oxide Semiconductor  Field Effect Transistors
  • is a 3-lead device, the lead names being source, drain and gate. (Examinations questions will be restricted to n-channel type devices.)

Candidates should be able to:

  • explain how an npn transistor and an n-channel MOSFET can be used as switches after gates, counters etc., as drivers to deliver power to an output device, and put this into practice
  • explain why a base resistor is needed for an npn transistor
  • compare the advantages and disadvantages of a MOSFET with a bipolar transistor
  • recognise and recall circuits which make use of the components given above.

Microcontrollers

Microcontrollers

Candidates should be able to:

  • describe the use and application of microcontrollers
  • know that a microcontroller is a programmable integrated circuit into which software can be loaded to carry out a range of different tasks
  • describe and explain the effect of microcontrollers on society.

Unit 5: Application of electronic systems

Audio systems

Applications of electronic systems

Candidates should be aware of the use of electronics in audio entertainment systems.

Audio systems


Candidates should be able to describe the function of each of the following subsystems of an audio entertainment system:

tuner

amplifier

microphone

loudspeakers

MP3, CD and DVD players and recorders.

Radio systems

Radio systems

Candidates should be able to:

  • draw and label the following block diagram of a simple radio receiver and explain how it works in terms of the functions of the subsystems


subsystems of a radio receiver

  • explain the meaning of the terms amplitude modulation (AM) and frequency modulation (FM)
  • sketch a voltage-time graph for an amplitude modulated wave with relation to its carrier wave and the modulating signal
  • sketch a voltage-time graph for a frequency modulated carrier wave with relation to its carrier wave and the modulating signal
  • compare the relative merits of FM and AM systems
  • explain the meaning of the terms sensitivity and selectivity.

Unit 6: Practical skills and processes

Practical skills and processes

Practical skills and processes

Practical work is an integral part of any course in electronics. Candidates should have a range of practical experiences, the skills from which will be required in their controlled assessment. Examiners are at liberty to deal with aspects of practical work in the written examination.

Candidates should be able to:

  • recognise a component from its physical appearance
  • use a catalogue or data sheet to select required component
  • draw a layout of a given circuit containing no more than 10 components using prototype board and showing all connections clearly
  • assemble a circuit following a circuit diagram
  • select and use a range of test instruments (e.g. multimeter, oscilloscope and signal generator)
  • identify simple faults in circuit diagrams and component layout.

Unit 7: Practical electronics system synthesis

Introduction

Introduction


Electronics Engineers often need to design a system that will solve a particular problem. The design produced will be based upon the engineer's knowledge of electronic subsystems which is brought together in an appropriate way to produce a final design that meets the user's requirements. In some cases, the proposed solution may have a wider impact on society in general.

Unit 2: Practical Electronics System Synthesis (controlled assessment) allows candidates to use the experience gained from the course to take a project from the design stage, having considered the specifications and options, through to construction, testing and evaluation. It will also involve research and communication skill which are vital aspects of bringing innovative solutions to production in the modern world.

All controlled assessment projects must have their foundation in the body of the content of Unit 1 of this specification.

Practical electronics system synthesis

Practical electronics system synthesis

There is one unit based upon a practical project.

Control of the assessment

Controll of the assesment

Control of the assessment is covered in the Section 3.8

Practical electronics system synthesis – skills

Practical electronics system synthesis - skills

The following four skills are to be assessed:

A. Planning

B. Realisation

C. Testing and Evaluation

D. Communication skills

Practical electronics system synthesis – marks

Practical electronics system synthesis - marks

Controlled assessments must be marked against the marking criteria given in Appendix E of this specification (amplification of the criteria is given in Section 3.9). There are 22 marking criteria giving total mark of 50, which constitutes 25% of the total marks for the award.

The marks for each skill area are in the ratio 7:7:5:6.

Practical electronics system synthesis – ownership

Practical electronics system synthesis - ownership

The project must be the work of the individual candidate and will have to be verified by both the candidate and supervisor. Group projects are not permitted. The marks awarded to candidates should reflect the achievement of the individual candidate referenced against the marking criteria.

Unit 8: Practical electronics system synthesis – project work

Guidance provided by AQA

Controlled assessment advisers will be available to provide guidance to centres.

Practical electronics system synthesis – project work

The following sections provide guidance on setting project work for the practical electronics system synthesis.

General approach

General approach

Candidates should identify a problem that can be solved using an electronic system. They should have developed the idea of breaking systems down into Inputs, Processes and Outputs. All projects should follow the same process of design, build, test, evaluate and report. The ideal design scenario would be for a candidate to use the components and subsystems covered in the course to generate a solution to an identified problem such that revision of the specification is also achieved. Components and systems from outside the scope of this specification may be used, but this should not be at the expense of the candidate's ability to access all of the marking points in the marking criteria. All candidates should have access to the 22 clearly defined assessment criteria and should be guided to work within that framework.

Candidates should be aware that while they may use circuit modelling software as part of their design process, credit is only given for work carried out on actual electronics hardware. Candidates must provide detailed explanations for any software that they use with programmable controllers e.g. PICs. It is expected that candidates will use a wide variety of research methods which will provide not only general research opportunities but will form the basis of a possible subsystem solution which may be used as part of the overall solution. In view of the time constraints and the limited experience of candidates the chosen project should be appropriate to the candidate's ability. Group projects are not permitted.

Candidates can only obtain marks for the work which they actually undertake.

Scope

Scope

Each controlled assessment project must have a minimum of one active device. No project need be attempted using circuits containing more than three to five active components (integrated circuits or transistors) or more than 20 to 25 passive components (resistors, capacitors or diodes, etc). As far as possible, candidates should be encouraged to identify problems of their own choosing and select a project of their own choice. The problem is unlikely to be totally original and the solution may not be unique given the level and nature of the course. However, it should provide a new experience for the candidate and be clearly set in an appropriate context. Mains operated projects and projects including controlling devices powered by mains contravene the Health and Safety at Work Act and are, consequently, not permitted by AQA. Further, OFCOM regulations require radio transmitters, tranceivers and power amplifiers to be approved on an individual basis. Projects involving such devices are not permitted.

The maximum voltage permitted in any project must be less than 30 V and total power consumption must be less than 100 W.

Approval

Approval

 
The project must be approved by the teacher responsible for supervising the candidate's work before the candidate embarks on any constructional work. When approving the project the supervisor should ascertain that:

  • the candidate has attempted to give a clear title and a specification for the project set in an appropriate context
  • the project is such that an able candidate could score every mark on the assessment scheme
  • the candidate can reasonably be expected to complete the work in the time available
  • all other projects in the teaching group are clearly different from the one being approved
  • the project does not lead to any Health and Safety problems.

Report

Report

All practical work must be under the direct supervision of the member of staff responsible for the prime marking of the controlled assessment or somebody delegated by them. The writing up and evaluation of the final report must be carried out under formal controlled conditions so that the member of staff responsible for prime marking is able to verify the authenticity of the candidates' work. The use of a research diary (see Section 3.8.6) should be encouraged so that candidates are able to verify the sources of information used in their final project report. The report should be a clear, straightforward communication of facts and ideas. Therefore, candidates should be given instructions on the presentation of information and be encouraged to use an appropriate style. The report must include clear photographic evidence of the final circuit. Photographs showing the stages of construction may also be incorporated into the report, but not at the expense of circuit diagrams. The report should include the following:

  • the proposed title of the project
  • the aims of the project and the context in which it is set
  • the analysis of the problem to be solved by the project
  • the information researched and investigations carried out prior to drawing up the specification
  • the specification of the solution
  • alternative solutions considered
  • the reasons for the selection of the chosen system
  • the design of the chosen solution/system
  • significant aspects of the development and progress
  • the methods of testing and modifications made during the construction
  • the testing methods employed after completion
  • test results appropriately tabulated
  • an assessment of how well the project works and an evaluation based on the original specification
  • suggestions for changes which make the circuit match the initial specification more closely
  • a statement of all sources of information and assistance received, cross-referenced within the report
  • reasons for all the decisions made.

Management

Management

Stage by stage submission and assessment are recommended in order to:

  • confirm the suitability of the project
  • encourage good practice by systematic approach to problem solving
  • permit early warning of problems
  • enable feedback to be given/detailed at all of the stages of the development of the project
  • enable necessary help to be given without invalidating the whole assessment
  • authenticate the candidate's work
  • make available a partial record in the event of candidate illness
  • ensure that less able candidates are able to attempt the implementation of a feasible design. 

Candidates should be encouraged to use a research diary, or something similar* during the research/data collection phases of the controlled assessment. The research diary can be used to record dialogue between the candidate and the teacher and also detail feedback and the amount of assistance given to the candidate at various stages of the realisation of the project. Where used, the research diary should be collected by the teacher when the task is complete and be used as a method of authenticating candidate's work. Research diaries should not be marked by the teacher, but should be retained by the centre until the deadline for enquiries about results.

It is expected that projects will be individual and it is therefore very unlikely that, during the analysis and evaluation stages of the controlled assessment, that candidates will be able to seek assistance from the Internet, magazines or reference books; should they wish to do this candidates should be discouraged from doing so.

A list of suggested topics for the project is given below. They are provided to illustrate the type of project which should prove appropriate. The suggestions are for guidance only and the list is by no means exhaustive:

alarm panic button, electronic metronome, alarm siren, fire alarm, anti-theft alarm, fishing bite alarm, audio amplifier, flashing unit, automatic cupboard light, flood light alarm system, automatic fan, fluid detector, automatic parking light, greenhouse temperature control, baby alarm, guitar tuner, battery tester, hair tongs alarm, bent wire game, headlight reminder, bicycle wheel revolutions counter, head/tails game, car park counter, intercom, chaser lights, infrared beam alarm, combination lock, kitchen timer, continuity tester, light activated target game, damp locator, light meter, door buzzer and light, light seeker, door chime, logic probe, electronic dice, low temperature warning, electronic keyboard, lottery number generator, low volts detector, simple AM radio, low water level indicator, smoke alarm, metronome, snooker scoreboard, motor direction control, sound activated alarm, morse keyer, sound effects generator, motion detector/alarm, sound locator, musical box, sound operated camera flash, optical fibre transmitter/receiver, sound switch, parking meter timer, sound to light unit, pH meter, steam detector, photographic light level detector, stopwatch, plant pot dryness indicator, stylus organ, porch security light, telephone call charger, pressure pad alarm, temperature monitor, quiz referee, time delay switch, rain detector, torch detector, random number generator, traffic light simulator, reaction timer, tripwire alarm, remote controlled location device, two-tone train horn, rhythm generator, ultrasonic control, safe alarm, variable egg timer, signal tracer, warbling buzzer.

Unit 9: Practical electronics system synthesis – marking criteria

PLANNING A1

Mark distribution

Mark distribution The skills to be assessed for the project and the mark distribution are given below.

A.     Planning                           14 marks

B.     Realisation of a system    14 marks

C.     Testing and Evaluation     10 marks

D.     Communication               12 marks

There are 22 marking criteria set out in this section, 21 of which may be awarded 0, 1, or 2 marks based upon how well each criterion has been met. The final marking criterion (D3) contains the assessment of QWC and allows for marks to be awarded in one of three mark bands. Further information regarding the allocation of marks for each criteria can be found later in this section and in the teacher resource bank for this specification.

Where a candidate deserves a particular mark but the necessary details have not been recorded in the report, the mark may be awarded providing that supporting information is given to the moderator by the teacher/supervisor at the point in the project report where the award would have been made.

In order for any marks to be awarded, an artefact must exist, even if not in working condition. This artefact must have a minimum, of one active device (an active device being one that produces power amplification e.g. an integrated circuit/transistor) connected to a suitable power supply. Clear photographic evidence must also exist.

The accepted medium for development, testing and presentation is on Breadboard/Prototyping board as this allows full access to the marking criteria based around the subsystem 'build and test' regime. Candidates may also present the final circuit on stripboard or p.c.b., but it is not a requirement of the specification.

The project shall not be admitted if it does not contain at least one active component as defined by the specification AND if there is no photograph of the final circuit construction.

Information relating to the criteria, amplification and marking are given on the following pages. 

PLANNING
A1

The candidate has independently identified a suitable problem to solve and has provided a title and an aim set in context.
Marks
0 The supervisor has helped the candidate to choose a problem. The aim and context is such that it is unclear how electronics is being used to solve the problem.
Amplification

Each candidate should be encouraged to select a suitable problem and to produce a clear and concise statement of the problem. The context should be stated so that it is clear how electronics is being applied to solve the problem.
1 The candidate makes an independent choice of problem but gives an inadequate aim and context so that it is difficult to see how electronics is being used to solve the problem OR receives assistance with the choice but gives a clear aim and context so that it is clear how electronics is being used to solve the problem.
2 The candidate makes an independent choice and provides an appropriate aim, the context has a detailed description of how electronics is being used to solve the problem.

PLANNING A2

PLANNING
A2

The candidate has analysed the system in terms of subsystems by producing a systems diagram of the solution.
Marks
0There is no evidence of a functional block diagram.
Amplification

The problem should be analysed so that the factors affecting the problem and its solution can be clearly identified. The problem should then be broken down into subsystems and consideration given to each in turn. The requirement is for the candidate to produce a system diagram, not a flowchart.
1There is evidence of a functional block diagram but unclear explanation of the functional sequence.
2There is well documented evidence of a functional block diagram and supporting explanation.

PLANNING A3

PLANNING
A3

The candidate has provided evidence of having carried out research, and made some selection of information gathered from at least two named sources.
Marks
0Inadequate evidence that research has been carried out from at least two separate named sources.
Amplification

In making decisions with regard to planning, the candidate is expected to consult the Internet, reference books, magazines and experts, as appropriate. In every case the source of advice must be acknowledged explicitly. The assessment is based on the extent to which the candidate sought out the necessary information and the use made of this information.
1Inadequate evidence documented OR inadequate details are given of at least two named sources.
2Well documented information from at least two separate sources whose full details are recorded.

PLANNING A4

PLANNING
A4

Well documented information from at least two separate sources whose full details are recorded.
Marks
0Inadequate evidence that a practical investigation has been conducted.
Amplification

The practical investigation should be undertaken on relevant factors e.g. on the suitability of transducers to be used as input or output devices. By targeting a specification e.g. the light level at which the alarm is triggered or the frequency at which the alarm must sound, the practical investigation can be used to generate one of the measurable target parameters in (A5).
1Clear evidence that a practical investigation has been carried out.
2Clear evidence that a practical investigation has been carried out and that
the results have been used to aid planning.

PLANNING A5

PLANNING
A5

The candidate has given at least two measurable quantitative, electronically relevant parameters for the specification.
Marks
0No electronically measurable parameters given within the specification.
Amplification

The key to the planning process lies in specifying the desired outcome numerically. The more quantitative the specification, the more realistically the candidate will be able to plan a feasible route to the solution. The specification should be a detailed statement of how the completed solution will perform and will include at least two relevant measurable electronic quantities which are specified precisely and in realistic terms. These quantitative items depend on the nature of the project and could be the supply voltage range, the current and power consumption, the input and output characteristics, the frequency or a time delay. Some examples of quantitative specifications are as follows:

* the power supply is 12 V dc ± 2 V
* the current consumption on stand-by is less than 10 mA, when active less than 50 mA
* the output device should give a sound intensity greater than 90 dB at a distance of 1 metre
* the device switches on at a light level of less than 100 lux
* the time delay is variable from 10 seconds to 100 seconds ± 5%.
1One electronically measurable parameter given with tolerance as part of the specification.
2Two electronically measurable quantities given with tolerance as part of the specification.

PLANNING A6

PLANNING
A6


The candidate has made a relevant calculation based upon component data.
Marks
0A suitably derived truth table would be acceptable in place of a mathematical calculation.
Amplification

Candidates should be encouraged to use up-to-date catalogues and data sheets in the selection of components to be used. The choice of the components and their values should be supported by reasons and relevant calculations where possible.

A suitably derived truth table would be acceptable in place of a mathematical calculation.
1A relevant calculation, perhaps containing errors in mathematics, the use of data or reasoning.
2A calculation in context, showing component data and free from errors in mathematics/reasoning.

PLANNING A7

PLANNING
A7

The candidate has drawn a labelled circuit diagram, with component values of the final system.
Marks
0No circuit diagram drawn OR one with significant omissions/errors.
Amplification

The chosen system should be fully documented in such a way that a competent third party could construct the system exactly as intended. The circuit diagram should be that of the final system and should have appropriate labels and component values. The diagram may be presented either in a single sheet format or in clearly defined and linked sections.
1A circuit diagram of the proposed system which a trained engineer could work from to recreate the project.
2A circuit diagram of the proposed system which a trained engineer could
work from to recreate the project.

REALISATION OF A SYSTEM B1

REALISATION OF A SYSTEM
B1

The candidate has produced a practical circuit board layout that is neat and logically organised.
Marks
0Disorganised layout even with guidance.
Amplification

The circuit board should be so organised as to allow the use of a multimeter, signal generator and oscilloscope without the risk of shorting other connections. It is also essential to organise the layout so that specific points of the circuit can be traced easily and excessively long wires/tracks avoided. The use of colour coded single strand wire can help in identifying power rails and signal routes on protoboard.
1Disorganised layout achieved with minimal guidance OR a well organised layout with guidance.
2Well organised layout achieved with minimal guidance.

REALISATION OF A SYSTEM B2

REALISATION OF A SYSTEM
B2

The candidate has produced a practical circuit board layout where polarised and active components are correctly orientated.
Marks
0No correct orientations achieved.
Amplification

The supervisor will award the marks in this section, but photographic evidence within the report may be used to confirm the award.
1At least two correct orientations achieved.
2All correct orientations achieved where more than two such components used.

REALISATION OF A SYSTEM B3

REALISATION OF A SYSTEM
B3

The candidate has adopted a safe approach to practical work.
Marks
0The candidate had to be closely supervised to avoid adopting unsafe
working practices.
Amplification

The candidate must adopt a safe and sensible approach to the use of equipment and components to promote a safe working environment for all users of the laboratory. The provision of a Risk Assessment by the candidate can be offered as evidence along with any observations made by the supervisor in support of these marks.
1Some awareness shown of risk assessment, safe techniques/procedures.
2Worked safely in all respects.

REALISATION OF A SYSTEM B4

REALISATION OF A SYSTEM
B4

The candidate has provided evidence that an input/output subsystem
works independently.
Marks
0Inadequate detail of how the subsystem works and the test done.
Amplification

Some evidence should be provided here to show that a subsystem functions in its own right, (e.g. the use of a simple timing diagram showing voltage levels when a switch is pushed and released). The report must clearly go beyond the statement 'it works' for this mark to be awarded.
1Incomplete detail of how the subsystem works and the test done.
2Full detail of how the system works and the test done.

REALISATION OF A SYSTEM B5

REALISATION OF A SYSTEM
B5

The candidate has provided evidence that a process subsystem works independently.
Marks
0Inadequate detail of how the subsystem works or the test done.
Amplification

As for B4 but this time for a processing subsystem. It is accepted that the processing subsystem will require a functioning input in order for the test to be carried out.
1Incomplete detail of how the subsystem works or the test done.
2Full details of how the system works and the test done.

REALISATION OF A SYSTEM B6

REALISATION OF A SYSTEM
B6

The candidate has provided evidence that the whole system works.
Marks
0No evidence provided of any three interacting subsystems working together.
Amplification

There should be evidence that the whole system works as a collective entity. The evidence for this may be provided by a statement that confirms the mode and sequence of operation implied in (A1, A2). The candidate is not allowed to use (B6) alone to satisfy either the award of (B4 and/or B5).
1Evidence given of three interacting subsystems working together.
2Evidence of the whole system working where that consists of more than
three interacting subsystems.

REALISATION OF A SYSTEM B7

REALISATION OF A SYSTEM
B7

The candidate has made systematic attempts to find and rectify faults (also award if no faults).
Marks
0No independent fault finding technique demonstrated.
Amplification

It is expected that faults would be corrected during the natural 'build, test and modify' regime applied to each subsystem. However, if there were no faults, the marks should still be awarded.
1Some evidence of independent fault finding.
2Some evidence of appropriate independent action to find and
successfully rectify a fault (award both marks if it works first time).

TESTING AND EVALUATION C1

TESTING AND EVALUATION
C1

The candidate has selected and used appropriate test equipment.
Marks
0 There is no evidence of any test equipment being used.
Amplification

These marks are awarded for the ability of the candidate to choose and use the appropriate test and measuring instruments. Regard should be given to the instrument range and sensitivity. Reference to the choice should be given in the report at the point where it was used.
1 Has identified appropriate test equipment and carried out a measurement with help.
2 Has identified appropriate test equipment and carried out an independent measurement.

TESTING AND EVALUATION C2

TESTING AND EVALUATION
C2

The candidate has recorded measurements relevant to at least two of the numerical parameters.
Marks
0There is no record of the appropriate measurements.
Amplification

Measurements should be made on the performance of the system and should be relevant to the two numerical parameters quoted in A5 as a minimum.
1Measurements are made and recorded but may be trivial or incomplete.
2The appropriate numerical measurements have been made and carefully recorded with units.

TESTING AND EVALUATION C3

TESTING AND EVALUATION
C3

The candidate has compared the actual working parameters of the circuit to the original parameters.
Marks
0There is little or no evidence of any comparison of the working parameters with the original parameters.
Amplification

Candidates are expected to compare the outcome with the major items in the original specification. If the specification in A5 is weak, high marks cannot be awarded. Comparison involves some basic comment by the candidate based upon the measurements made.
1There is some attempt to evaluate the final measurements against the original specification, but the consequences of the evaluation may not be appreciated.
2All relevant numerical measurements on the system parameters have been made, recorded and evaluated.

TESTING AND EVALUATION C4

TESTING AND EVALUATION
C4

The candidate has carried out or suggested an improvement (also award if no improvement is needed).
Marks
0The system does not meet the specification and no improvement is suggested/carried out.
Amplification

These marks are to be awarded for improvements made or suggested that enable or would enable the system to meet the original specification better. Systems that do not require such improvements should be awarded the marks.
1The system does not meet the full specification and one improvement is suggested/carried out.
2There is a clear statement of how the improvement would or does make the system perform more closely to the intended specification. (Award if no modifications are needed).

TESTING AND EVALUATION C5

TESTING AND EVALUATION
C5

The candidate has developed their own project.
Marks
0The candidate required significant assistance and guidance throughout their project.
Amplification


These marks relate directly to the candidate's own input to the thinking and decision making. As always, discussion with the supervisor in clarifying a candidate's thinking must not be confused with dependence on the supervisor for ideas, decision making and problem solving. Originality is to be interpreted in the context of the experience of an able 16-year-old but it must be discernible and significant.
1The candidate required some assistance and guidance in the planning and realisation of their project.
2The candidate completed their project with minimal assistance and guidance.

COMMUNICATION SKILLS D1

COMMUNICATION SKILLS
D1

The candidate has produced a report that contains clear photographic evidence and carefully produced illustrations.
Marks
0There is no photograph of the final artefact in the report AND/OR the illustrations are of poor quality.
Amplification

Circuit diagrams and photographs should form an integral part of the report. This skill relates to the quality and usefulness of those diagrams and photographs. A detailed photograph of the final solution not only aids moderation, but contributes to D3, and provides supporting evidence for B1, B2 and B3.
1There is a clear picture of the final artefact in the report together with a fully labelled circuit diagram.
2There is a clear picture and fully labelled circuit diagram of the final artefact together with intermediate diagrams/illustrations/pictures that allows the reader better access to the technical aspects of the report.

COMMUNICATION SKILLS D2

COMMUNICATION SKILLS
D2

The candidate has produced a report that contains tabulated/graphical results with appropriate symbols and units.
Marks
0No table or graph as defined in the amplification section of the GCSE specification is presented.
Amplification

These marks are awarded for any relevant graph, table of the initial and final numerical specifications, a derived truth table or any other tabulated results taken from the performance of a component/system. Performance results are expected to have been recorded by the candidate on real circuits and should be presented as a boxed table with appropriate headings and units.
1A table or a graph may be presented but is lacking in technical detail as defined in the amplification section of the specification.
2A full table or graph is presented matching the technical requirements in the amplification section of the specification.

COMMUNICATION SKILLS D3

COMMUNICATION SKILLS
D3

The candidate has produced a report that adequately documents the development and outcome of the project.
Marks
0-2The report covers some aspect of the development but not in any detail.
The report is rarely:
i) accurate in spelling, punctuation and grammar such that the meaning is unclear.
ii) organised, such that the format is unhelpful and no specialist terms have been used, or used in the wrong context.
Amplification
This skill refers to the format and content of the report and the Quality of Written Communication (QWC). The report should be written in stages that form a logical sequence and cover all major aspects of planning, development, construction, test and evaluation. Within this context, levels of QWC will be assessed on a three banded mark scheme. When assessing the communication skill, the criteria should have been addressed across the majority of the report for the appropriate award of marks to be made.
3-5The report covers some aspects of the development and testing and there will be detailed analysis of at least one subsystem.
The report is sometimes:
i) accurate in spelling, punctuation and grammar so that the overall meaning is clear.
ii) organised, such that the format and the use of specialist terms has been successful in places.
6-8The report covers most aspects of the development and testing of the full system including two valid reasons of the selection of the system from alternatives that would fulfil the same requirement. The report is mostly:
i) accurate in spelling, punctuation and grammar so that the meaning is clear.
ii) well organised with a clear format and contains specialist vocabulary where appropriate.

Unit 10: How Science Works

How Science Works

How Science Works is an underpinning set of concepts and is the means whereby students come to understand how to explain the world about us. Moreover, How Science Works recognises the contribution that science, and in particular electronics, has made to the wider world. It acknowledges that scientists can, and must, contribute to debates about the uses to which their work is put and how their work influences decision-making in society.

In general terms How Science Works can be used to promote students' skills in solving scientific problems by developing an understanding of

  • the concepts, principles and theories that form the subject content 
  • the procedures associated with the valid testing of ideas and, in particular, the collection, interpretation and validation of evidence.

As students become proficient in these aspects of How Science Works, they can also engage with the place and contribution of electronics in the wider world. In particular students will begin to recognise:

  • the contribution that scientists can make to decision-making and the formulation of policy 
  • the need for regulation of scientific enquiry and how this can be achieved 
  • how scientists can contribute legitimately in debates about those claims which are made in the name of science.

Examples of where How Science Works can be incorporated into the teaching of this specification include:

A.  Use theories, models and ideas to develop and modify scientific explanations; Unit 1, Sections 3.2.1 and 3.2.2

 

B.  Use knowledge and understanding to pose scientific questions, define scientific problems, present scientific arguments and scientific ideas; Unit 2

 

C.  Use appropriate methodology, including ICT, to answer scientific questions and solve scientific problems; Unit 1, Sections 3.2.2 and 3.4 and Unit 2

 

D.  Carry out experimental and investigative activities, including appropriate risk management, in a range of contexts; Unit 1, Sections 3.3 and 3.6 and Unit 2

 

E.  Analyse and interpret data to provide evidence, recognising correlations and causal relationships; Unit 1, Section 3.6 and Unit 2

 

F.  Evaluate methodology, evidence and data, and resolve conflicting evidence; Unit 2

 

G. Appreciate the tentative nature of scientific knowledge; Unit 2

 

H.  Communicate information and ideas in appropriate ways using appropriate terminology; Unit 1, Sections 3.2.1, 3.2.2 and 3.3.2 and Unit 2

 

I.  Consider applications and implications of science and appreciate their associated benefits and risks; Unit 1, Section 3.5

 

J.  Consider ethical issues in the treatment of humans, other organisms and the environment; Unit 1, Section 3.4.4

 

K.  Appreciate the role of the scientific community in validating new knowledge and ensuring integrity; Unit 1, Sections 3.4.4 and 3.7.1 and Unit 2

 

L.  Appreciate the ways in which society uses science to inform decision making; Unit 1, Sections 3.4.4 and 3.5

Unit 11: Mathematical requirements

Mathematical requirements

The knowledge and skills in mathematics which are relevant to this GCSE Electronics specification are:

  • the four basic rules of addition, subtraction, multiplication and division of decimal numbers
  • drawing and interpreting graphs
  • use of prefixes such as mega, kilo, centi, milli, micro, nano and pico
  • the binary representation of positive integers
  • transformation of simple formulae.