GCSE Electronics Practical Electronics System Synthesis Report on the Examination June Version: 1.0

Transcription

1 GCSE Electronics Practical Electronics System Synthesis Report on the Examination 4430 June 2013 Version: 1.0

2 Further copies of this Report are available from aqa.org.uk Copyright 2013 AQA and its licensors. All rights reserved. AQA retains the copyright on all its publications. However, registered schools/colleges for AQA are permitted to copy material from this booklet for their own internal use, with the following important exception: AQA cannot give permission to schools/colleges to photocopy any material that is acknowledged to a third party even for internal use within the centre.

3 General Comments There was further evidence this year that the Controlled Assessment was acting as a focus point for candidates and that it was making a positive contribution to the overall award. More candidates were providing evidence of robust planning followed by a rigorous build and test regime, something that is central to the ethos of the Controlled Assessment in this subject. However, there was also some evidence through the moderation that there was a detectable drift away from the standards set for the criteria and prime markers are encouraged to seek advice if unsure about specific aspects. It was reported that a number of CDFs were missing this year, but otherwise the administration was good both in the provision of samples and in the documentation. As reported last year, it remains the aim of the Controlled Assessment within this specification to get candidates to address the following points: i) Follow a problem solving exercise where the solution is based on electronics and set within a clear context. ii) Produce measurable numerical specifications for the proposed solution aided by a practical investigation. iii) Produce a block by block subsystem design primarily based on the material covered in the course. iv) Adopt a build and test regime as the subsystems are realised on breadboard. v) Produce an evaluation of the results of the tests against the original specification quoted. vi) Suggest how improvements to the results might be achieved and consider alternative circuits that could be used in the design to achieve an equivalent solution. The following general points were noted from the sample of scripts moderated this year. Use of microcontrollers: Only a very small number of PIC systems were evident this year. However, for those new to the course, it should be remembered that although such devices are allowed, such software controlled devices are treated as being neutral when applying the marking criteria. Complexity of circuits: There were again some very good and complex systems submitted by more able pupils. Supervisors are advised to make it clear to such candidates where a project stops, and an assessment begins. It is always disappointing to find such candidates falling short on the assessment objectives as their focus becomes totally directed by the complexity of the project. Similar Projects: Just one or two Centres submitted large quantities of reports based around either the same component or idea. Centres are reminded that there must be sufficient evidence to show that each project is different from others in the group. This should be possible by making use of a wider range of components covered in the course rather than just changing the context. One of the objectives of the controlled assessment is that it should form the basis of revision of the factual knowledge in the course, so it is always good to see candidates employing a number of the basic subsystems. 3 of 5

4 Numerical specification: A good set of measurable numerical specifications with tolerances lies at the heart of a good project and report and these must come early on in the planning stage. It is assumed that the measurements are made using some form of meter. A number of Centres / candidates did not give this aspect of the planning sufficient consideration resulting in a poor return on some of the planning, testing and evaluation marks. Note: A specification that says that the buzzer should be audible at the back of the room will lead to a poorer return on marks than if the specification had said the alarm should produce a sound of 75dB +/- 2dB at 5 metres. Similarly, a frequency of 1kHz +/- 10% is better than saying about 1kHz. Circuits from the internet / magazines: There was less evidence this year of circuits being taken directly from the internet or magazines. This was encouraging as this approach rarely allows candidates to show an understanding of design, subsystem function, investigation or specification as much of this is already provided by the circuit being copied. The build and test approach of each subsystem becomes lost to candidates following this approach as does the ability to draw a circuit diagram (A7) rather than just copy one. Centres are therefore asked to continue to discourage this practice unless it is appreciated by both candidates and prime markers that some marks will not be accessible and others cannot be supported. Annotation: Prime marker annotation for the allocation of marks this year was good. However, there is still work to be done on this by a few Centres. The annotation must be shown at the point where the evidence is to be found. A detailed statement should be given by the prime marker in the support of any award where candidate evidence does not exist. References: These are getting better, although some candidates still do not provide sufficient detail or indicate the information gained or used. The references should be detailed and should be shown both at the point of use and in the Bibliography. A book name, author, publisher and page number would be expected as would a full web address. (Not the search engine). Photographic evidence / verification: Centres are reminded that the Controlled Assessment will not be admitted unless there is photographic evidence of the final circuit. This year, photographs were increasingly used as supporting evidence for testing. This is to be encouraged, but should not be used as a replacement for circuit diagrams of the subsystem under discussion. The photograph of the full and final system should be in close-up to support the award of B1 and B2. Subsystems: As reported last year, some candidates continued to struggle with the concept of a subsystem. A subsystem should be seen as a single stage of the circuit from which a signal is generated or through which the signal passes whilst being processed. In some cases this may only consist of two components e.g. switch resistor chain or an LED and protective resistor. Report writing: Whilst some candidates offer a report that follows the marking criteria in the order set out in the specification, this tends not to lead to a clear explanation as to how the circuit was developed, built and tested. The best format remains that based on the subsystems taken in operational sequence. 4 of 5

5 CD s and Diaries: Most of the work was submitted as expected as an A4 word processed document. Centres are again asked not to send video evidence on DVD s and project diaries should be kept secure with the circuit until after the results have been published. Mark Ranges and Award of Grades Grade boundaries and cumulative percentage grades are available on the Results Statistics page of the AQA Website. Converting Marks into UMS marks Convert raw marks into Uniform Mark Scale (UMS) marks by using the link below. UMS conversion calculator 5 of 5