What is the non-exam assessment, and how is an electronic system designed, built, tested and evaluated?
An overview of Component 3, the extended system design and realisation task (the non-exam assessment): analysing a problem, writing a design specification, developing and testing sub-systems, building and testing the complete system, and evaluating it against the specification.
A concise overview of Component 3 of WJEC Eduqas GCSE Electronics, the non-exam assessment, covering analysing a problem, writing a specification, developing and testing sub-systems, building and testing the system, and evaluating it.
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What this topic is asking
WJEC Eduqas wants you to understand Component 3, the extended system design and realisation task - the non-exam assessment (NEA) worth 20% of the GCSE. This is a practical project in which you design, build, test and evaluate your own electronic system. This page is a concise overview of the stages and what is assessed; the detailed engineering knowledge it draws on is covered across Components 1 and 2.
What Component 3 is
Unlike the two written papers, Component 3 is assessed from the work you produce over the project, not in an exam. It is where the theory becomes a real, working circuit. Because it is worth a fifth of the GCSE, it rewards careful, methodical design and clear documentation as much as a circuit that works.
The design stages
Each stage builds on the last. Analysis works out exactly what is needed. The specification turns this into measurable targets (such as the temperature at which a fan must switch on, or a required time delay), which guide the whole project. Development designs and tests each sub-system in turn, then combines them; realisation builds and tests the whole physical circuit. Finally, evaluation judges the finished system against each specification point and proposes improvements. This is the systems approach (input, process, output) applied end to end.
How it draws on the rest of the course
There is little genuinely new theory in Component 3; instead it is where everything else is used. A typical project senses something (an input sub-system), makes a decision (a process sub-system such as a comparator, logic, a 555 timer or a microcontroller), and drives an output (through a transducer driver). Choosing, calculating and testing these sub-systems is exactly the work practised throughout Components 1 and 2, now brought together in one product with proper testing and documentation.
Try this
Q1. State the five main stages of the extended system design and realisation task. [3 marks]
- Cue. Analyse the problem; write a measurable specification; develop and test sub-systems; build and test the complete system; evaluate against the specification.
Q2. State why the design specification should contain measurable criteria. [1 mark]
- Cue. So each sub-system and the finished system can be tested and evaluated against clear targets.
Exam-style practice questions
Practice questions written in the style of WJEC exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Eduqas style4 marksDescribe the main stages of the extended system design and realisation task, from analysing the problem to evaluating the finished system.Show worked answer →
A Component 3 overview question. The main stages are: analyse the problem or opportunity to understand what is needed (1 mark); write a design specification with measurable criteria for the solution (1 mark); develop and test the sub-systems (input, process, output) and then build and test the complete system (1 mark); and evaluate the finished system against the specification, suggesting improvements (1 mark). Markers reward the logical design sequence: analyse, specify, develop/build and test, evaluate. A common error is to leave out testing or the final evaluation.
Eduqas style3 marksExplain why a design specification with measurable criteria is important in the realisation task, and how it is used at the end.Show worked answer →
A Component 3 Explain question. A design specification sets out measurable criteria the solution must meet (for example a switching temperature, a time delay, a supply voltage) (1 mark). It guides the design and testing, because each sub-system can be checked against a clear target (1 mark). At the end, the finished system is evaluated against the specification to judge how well it meets each criterion and what could be improved (1 mark). Markers reward measurable criteria, guiding the build/test, and being the basis of the final evaluation. A common error is to give vague, unmeasurable aims.
Related dot points
- The systems approach to electronics: the input (sensing), process and output sub-systems, the use of system block diagrams, common input sensors, processing units and output devices, and why transducer drivers are needed between a processing sub-system and an output device.
A focused answer to WJEC Eduqas GCSE Electronics on the systems approach, covering the input, process and output sub-systems, system block diagrams, common sensors, processing units, output devices and why a transducer driver is needed.
- The voltage comparator as an integrated-circuit switching circuit that compares an input voltage with a reference, the use of a potential divider to set the reference and threshold, and interface circuits (including a relay or transistor driver) to switch an output.
A focused answer to WJEC Eduqas GCSE Electronics on the voltage comparator and interfacing, covering how a comparator switches at a threshold set by a potential divider, and how a relay or transistor driver interfaces the output to a load.
- The microcontroller as a programmable integrated circuit, how sensors and output devices are interfaced to it, designing and analysing a control program as a flowchart, and why microcontrollers are now used so widely.
A focused answer to WJEC Eduqas GCSE Electronics on microcontrollers, covering the microcontroller as a programmable IC, interfacing sensors and outputs, designing and analysing a control program as a flowchart, and why microcontrollers are so widely used.
- The potential divider: how two resistors share a supply voltage, the potential divider equation, and designing and analysing a divider to produce a required output voltage.
A focused answer to WJEC Eduqas GCSE Electronics on potential dividers, covering how two resistors share a supply voltage, the potential divider equation, and designing and analysing a divider for a required output voltage.
- The npn bipolar transistor and the n-channel enhancement MOSFET used as switches: how a small input controls a larger output current, the meaning of saturation and cut-off, and the differences between the two devices.
A focused answer to WJEC Eduqas GCSE Electronics on transistor and MOSFET switching, covering how an npn transistor and an n-channel enhancement MOSFET act as switches, saturation and cut-off, and the differences between the two devices.
Sources & how we know this
- WJEC Eduqas GCSE Electronics specification (from 2017) — WJEC Eduqas (2017)