Homeschool Guide: These lesson plans are a guide for parents. Content may contain errors — always cross-reference with official exam board specifications.

diodes & transistors

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4 detailed 50-minute lessons with teaching scripts, worked examples, parent guides, and assessment criteria.

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Lesson Overview

Total Lessons: 4
Tier: Foundation and Higher
Duration: 50 minutes per lesson (200 minutes total)
Exam Boards: AQA, Edexcel, OCR, Eduqas, CCEA

Learning Objectives

Prerequisites

Materials & Equipment

Lesson 1: Introduction: diodes & transistors

Duration: 50 minutes

Starter Activity (5 minutes)

Quick Recall

Write down everything you already know about diodes & transistors. Then check against the key terms: key terms from diodes & transistors. Use a mini-whiteboard or paper.

Main Content (35 minutes)

Parent/Teacher Guide:
Before lesson: Read the script below. Pre-teach key vocab: key terms from diodes & transistors.
If stuck: Re-read the revision notes (link above), then break the content into smaller steps.
Extension: See the Stretch & Challenge ideas in Lesson 4.
Teaching Script (35 mins):
Mins 0-5 - Hook: "Today: diodes & transistors. By the end you will be able to answer exam questions on it unaided. It connects to the rest of Electronics because the ideas here recur across the spec."
Mins 5-20 - Direct Instruction: Work through the core ideas below one at a time; after each, ask your student to explain it back in their own words.
Mins 20-30 - Guided Practice: Model the worked example together, then let your student attempt the first practice question with guidance.
Mins 30-35 - Independent Practice: 2-3 practice questions from Lesson 3 below, with immediate feedback.
First Look

Start with the revision notes summary, then attempt: explain the key ideas of diodes & transistors

Plenary (5 minutes)

Check Out

Your student states one thing they learned and one question they still have about diodes & transistors.

Lesson 2: Core Concepts: diodes & transistors

Duration: 50 minutes

Starter Activity (5 minutes)

Review Previous Lesson

Quick recap: write 3 key points from Lesson 1 on diodes & transistors. Check them against the notes below.

Main Content (35 minutes)

Key Fact: A semiconductor diode allows current to flow in one direction only; it has a forward voltage drop of about 0.7 V for silicon.
Key Fact: An LED (light-emitting diode) emits light when forward biased; it requires a series resistor to limit current.
Key Fact: A bipolar junction transistor (BJT) has three terminals: base, collector and emitter.
Key Fact: An NPN transistor switches on when the base-emitter voltage exceeds ~0.7 V, allowing collector current to flow.
Key Fact: In switching mode, a transistor is driven between cut-off (off) and saturation (fully on).
Key Fact: Current gain h_FE = I_C/I_B; a small base current controls a much larger collector current.

Practice (10 minutes)

Q: explain the key ideas of diodes & transistors

Answer:

Plenary (5 minutes)

Explain Back

Your student teaches the key points back to you without looking. Fill any gaps immediately.

Lesson 3: Application: diodes & transistors

Duration: 50 minutes

Starter Activity (5 minutes)

Quick Recall

Recall the key terms: key terms from diodes & transistors. Define each in one sentence.

Main Content (35 minutes)

Parent/Teacher Guide: Let your student attempt each question alone first, then compare with the model answer. Award method marks for correct working even if the final answer is wrong.

Work through the practice questions on the revision notes page for this topic.

Plenary (5 minutes)

Error Review

Review any questions answered incorrectly. Identify whether the error was knowledge, method, or reading the question.

Lesson 4: Exam Practice: diodes & transistors

Duration: 50 minutes

Starter Activity (5 minutes)

Command Words

Review what these command words require: state (one point), describe (say what happens), explain (say why), compare (both sides), evaluate (judgement).

Main Content (35 minutes)

Extended Answer

Extended question: Full-Mark Response Explain how a bipolar junction transistor can be used both as an electronic switch and as an amplifier. <div class="

A bipolar junction transistor (BJT) has three terminals: base, collector and emitter. A small base current I_B controls a larger collector current I_C, where I_C = h_FE × I_B. As a switch, the transistor is driven between two states: cut-off (no base current, no collector current, switch open) and saturation (base current sufficient to allow maximum collector current, switch closed). A logic-level input at the base turns the load on or off. As an amplifier, the transistor is biased into the active region between cut-off and saturation. A small varying input signal at the base produces proportional variations in collector current, resulting in a larger output signal at the collector. In a common-emitter configuration, the amplifier provides voltage, current and power gain but inverts the signal. The bias components set the operating point so the output can swing symmetrically without clipping.

Exam Tips: Always include a series resistor when calculating LED circuits. | State the value of V_BE (0.7 V for silicon) before using it in calculations. | For switching circuits, verify the transistor is in saturation by checking I_C < h_FE × I_B. | Label base, collector and emitter clearly on any circuit diagram. | Remember that a common-emitter amplifier inverts the output signal.
Common Errors: ✗ Omitting the series resistor for an LED in a circuit diagram. ✓ An LED must always have a series resistor to limit current to a safe value. ✗ Confusing NPN and PNP transistor biasing. ✓ NPN turns on when base is higher than emitter by ~0.7 V; PNP turns on when base is lower than emitter. ✗ Assuming a transistor in saturation has a large V_CE. ✓ In saturation, V_CE(sat) is very small, typically 0.2 V or less. ✗ Forgetting to check that the base resistor provides enough current for saturation. ✓ Calculate I_B = (V_in − 0.7)/R_B and verify I_C = h_FE × I_B exceeds the load current needed.
Stretch & Challenge (Grade 8-9):
  • Synoptic links: explain how diodes &amp; transistors connects to another Electronics topic you have studied
  • Real-world: research one real-world use or example of diodes &amp; transistors
  • Critical: "What are the limitations of the models used in diodes &amp; transistors?"

Plenary (5 minutes)

Assessment Criteria
  • Got it: Confident explanation + correct worked examples
  • Getting there: Main points OK, needs support with detail
  • Not yet: Confused on key concepts - re-run Lesson 2

Homework & Consolidation

Recommended Resources

🎓 Smart Lesson (Guided)