Developing an electronics outcome (internal)
Internal 6 credits Circuits Microcontrollers Sensors Safety TestingAS 91894, 6 credits — the joint-largest DigiTech internal at this level. Advanced electronics techniques serving the purpose and end users, with testing, EXPLAINING interfaces/functions, and implications — plus a genuine safety dimension, on the shared develop → informed → refined ladder.
1 Reading the notation
Explaining interfaces is Achieved; evaluating component choice is Merit; justifying it is Excellence.📖 Terms the schedule grades you on
4 terms- Develop (Achieved)
- Functional outcome to specifications; test/debug; EXPLAIN interfaces/functions; explain implications.
- Informed (Merit)
- Identify behaviour/function; test/modify for RELIABILITY; EVALUATE component choice; address implications.
- Refined (Excellence)
- Iterative improvement throughout; JUSTIFY the components and systems chosen.
- Relevant implications (closed list)
- Social, cultural, legal, ethical, intellectual property, privacy, accessibility, usability, functionality, aesthetics, sustainability & future-proofing, end-user considerations, health and safety.
2 What each grade requires
The develop → informed → refined ladder shared across the "advanced techniques" family.| Grade | What it takes | The half people drop |
|---|---|---|
| Achieved | Advanced techniques for the purpose/end users; data integrity and testing; EXPLAIN implications | Explaining an implication in the abstract, unconnected to this outcome |
| Merit ("informed") | Use information FROM TESTING to improve quality; ADDRESS implications with a visible decision | Testing that never feeds back into an actual change |
| Excellence ("refined") | ITERATIVE improvement across design/development/testing; JUSTIFY the choices made | One single round of testing, not a genuine iteration loop |
The verb escalates every time: explain → address → justify. Each is a distinct, checkable action, not just "more effort".
3 Choosing components and conditioning signals
The requirement drives the choice — and evaluating that choice is Merit-level evidence.The build sequence
- Write the end-user requirements as testable statements.
- Breadboard and test each subsystem alone — sensor, then output, then logic.
- Add signal conditioning where the raw signal needs it, and say why.
- Integrate one subsystem at a time, testing after each.
4 Safety and data integrity
A genuine implication, not a formality — and the most commonly omitted protective component. ✕The missing flyback diode
Switching a motor, relay or solenoid from a microcontroller pin without a flyback diode across the load lets the collapsing magnetic field push a reverse voltage spike back into the circuit. It is the most commonly omitted protective component, and it destroys transistors and microcontrollers.5 Documentation and testing scope
Could someone else rebuild it from the documentation alone?What complete documentation includes
- A circuit diagram with correct symbols.
- A component list with values and ratings.
- Pin assignments and commented firmware.
- Test evidence covering expected, boundary AND invalid inputs.
Practice
Recall it first, then use it — testing yourself builds the memory, where rereading the notes above only feels easier.
Recall and application shuffled together — you have to work out what each item wants before you can answer it, which is the part the exam actually tests. Both kinds feed the same spacing schedule, so anything you miss comes back sooner.
Say the answer out loud before flipping — that attempt is where the learning happens, even when you get it wrong.
Exam-style only. Instant feedback, shuffled each attempt, best score saved on this device.