Case study·Standard multi-step (3/5)·No calculator
Difficulty guide
The label describes the problem, not your ability.
1/5 - Foundational
Warm-up setup; checks one basic idea.
2/5 - Routine exam skill
Normal syllabus skill; usually one main rule or interpretation.
3/5 - Standard multi-step
Exam-style problem with multiple steps or a common trap.
4/5 - Hard exam skill
High-end exam problem; combines methods carefully.
5/5 - Challenge
Stretch problem beyond normal exam pressure.
Question
A lab group records these diode readings. In forward bias, current is nearly zero up to about and then rises quickly. In reverse bias, current remains very small for the voltages used.
Total: 5 marks
(a) What feature of the forward characteristic is near ? (1 mark)
(b) What does the small reverse current show about the diode? (1 mark)
(c) Is the diode ohmic? Give a reason. (2 marks)
(d) Name one application that follows from this behaviour. (1 mark)
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