p5 circuit basics
4 detailed 50-minute lessons with teaching scripts, worked examples, parent guides, and assessment criteria.
Lesson Overview
Total Lessons: 4
Tier: Foundation and Higher
Duration: 50 minutes per lesson (200 minutes total)
Exam Boards: AQA, Edexcel, OCR, Eduqas, CCEA
Tier: Foundation and Higher
Duration: 50 minutes per lesson (200 minutes total)
Exam Boards: AQA, Edexcel, OCR, Eduqas, CCEA
Learning Objectives
- Explain the key ideas of p5 circuit basics
- Apply p5 circuit basics to exam-style questions
- Develop independent study skills
- Build cross-topic connections
Prerequisites
- Read the revision notes for p5 circuit basics first (GCSE Revise summary)
- Key vocab to pre-teach: Electric current, Potential difference (voltage), Resistance
- Basic skills: reading the summary notes and answering the practice questions there
Materials & Equipment
- Exercise book, coloured pens
- Scientific calculator
- Ruler
- Printed revision notes (link below)
- Internet for videos (see Resources)
Lesson 1: Introduction: p5 circuit basics
Duration: 50 minutes
Starter Activity (5 minutes)
Quick Recall
Write down everything you already know about p5 circuit basics. Then check against the key terms: Electric current, Potential difference (voltage), Resistance. Use a mini-whiteboard or paper.
Main Content (35 minutes)
Parent/Teacher Guide:
Before lesson: Read the script below. Pre-teach key vocab: Electric current, Potential difference (voltage), Resistance.
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.
Before lesson: Read the script below. Pre-teach key vocab: Electric current, Potential difference (voltage), Resistance.
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: p5 circuit basics. By the end you will be able to answer exam questions on it unaided. It connects to the rest of Combined Science (Trilogy) 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.
Mins 0-5 - Hook: "Today: p5 circuit basics. By the end you will be able to answer exam questions on it unaided. It connects to the rest of Combined Science (Trilogy) 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: Foundation Name the component that measures current and state how it is connected in a circuit.
Plenary (5 minutes)
Check Out
Your student states one thing they learned and one question they still have about p5 circuit basics.
Lesson 2: Core Concepts: p5 circuit basics
Duration: 50 minutes
Starter Activity (5 minutes)
Review Previous Lesson
Quick recap: write 3 key points from Lesson 1 on p5 circuit basics. Check them against the notes below.
Main Content (35 minutes)
Electric current: The rate of flow of charge. Measured in amperes (A) using an ammeter connected in series. Current is the same in all parts of a series circuit.
Potential difference (voltage): The energy transferred per unit charge passing between two points. Measured in volts (V) using a voltmeter connected in parallel across the component.
Resistance: The opposition to the flow of current. Measured in ohms (Ω). Higher resistance means less current for a given voltage.
Ohm's Law: The current through a resistor at constant temperature is directly proportional to the potential difference across it. This means V = I x R.
Required practical: Investigate the I-V characteristics of a resistor, a filament lamp and a diode to see how current varies with potential difference.
Applications: Thermistors are used in temperature sensors (e.g. thermostats, car engine temperature sensors). LDRs are used in light sensors (e.g. automatic street lights, burglar alarms, camera light meters).
| Term | Meaning | Example |
|---|---|---|
| Cell | Long line (+) and short thick line (-) | Provides energy to the circuit |
| Battery | Two or more cells joined together | Long line = positive terminal |
| Switch (open) | Gap in the circuit line | Circuit is incomplete — no current |
| Switch (closed) | Line completes the circuit | Circuit is complete — current flows |
| Lamp | Circle with a cross inside | Converts electrical energy to light |
| Resistor | Rectangle | Opposes current flow at constant rate |
| Variable resistor | Rectangle with diagonal arrow | Resistance can be changed |
| Ammeter | Circle with 'A' inside | Connected in series, measures current |
Practice (10 minutes)
Q: Foundation Name the component that measures current and state how it is connected in a circuit.
Answer: An ammeter measures current. It is connected in series with the component — the current flows through it.
Plenary (5 minutes)
Explain Back
Your student teaches the key points back to you without looking. Fill any gaps immediately.
Lesson 3: Application: p5 circuit basics
Duration: 50 minutes
Starter Activity (5 minutes)
Quick Recall
Recall the key terms: Electric current, Potential difference (voltage), Resistance. 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.
Q1: Foundation Name the component that measures current and state how it is connected in a circuit.
Answer: An ammeter measures current. It is connected in series with the component — the current flows through it.
Q2: Foundation A resistor has 8 V across it and a current of 2 A flows through it. Calculate its resistance.
Answer: R = V / I = 8 / 2 = 4 Ω.
Q3: Foundation Describe the difference between the I-V graph of a resistor and a filament lamp.
Answer: A resistor (at constant temperature) gives a straight line through the origin — current is directly proportional to voltage (Ohmic). A filament lamp gives a curved graph that flattens at higher voltages — as current increases, the filament heats up and resistance increases, so current increases more slowly (non-Ohmic).
Q4: Higher A thermistor is connected to a 5 V supply. At 25 °C its resistance is 1000 Ω. At 100 °C its resistance is 100 Ω. Calculate the current at each temperature and explain the difference.
Answer: At 25 °C: I = 5 / 1000 = 0.005 A = 5 mA. At 100 °C: I = 5 / 100 = 0.05 A = 50 mA. The current is much higher at 100 °C because the thermistor's resistance decreases as temperature increases (more charge carriers are released), allowing more current to flow.
Q5: Higher Explain why a diode only allows current to flow in one direction. How would this appear on an I-V graph?
Answer: A diode has very low resistance in the forward direction (allows current through) but very high resistance in the reverse direction (blocks current). On the I-V graph: there is current in the forward direction (positive voltage), rising steeply once the threshold voltage is exceeded. In the reverse direction (negative voltage), the current is essentially zero.
Q6: Higher A student investigates the I-V characteristics of a resistor. They vary the voltage and measure the current. State one safety precaution and one way to improve accuracy.
Answer: Safety precaution: do not exceed the maximum voltage rating of the resistor to avoid overheating/burning out. Improving accuracy: take multiple readings and calculate a mean, or use smaller voltage increments to get more data points for a smoother graph.
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: p5 circuit basics
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: Extended Answer 6 marks: Compare the I-V characteristics of a resistor, a filament lamp and a diode. Include descriptions of the graph shapes and explanations for each. <div class="
A resistor at constant temperature is an Ohmic conductor. Its I-V graph is a straight line through the origin, meaning current is directly proportional to voltage. The resistance remains constant. A filament lamp is a non-Ohmic conductor. Its I-V graph is a curve that flattens at higher voltages. As current increases, the filament heats up, the metal ions vibrate more, and resistance increases, so current increases less quickly. A diode only allows current to flow in the forward direction (forward bias). On the I-V graph, current is zero in reverse bias and rises steeply once the threshold voltage (~0.6 V) is exceeded in forward bias. The diode has very high resistance in reverse and very low resistance in forward bias above the threshold. Mark scheme: 1 mark — resistor straight line / Ohmic, 1 mark — resistance constant, 1 mark — lamp curves / non-Ohmic, 1 mark — resistance increases with temperature, 1 mark — diode conducts in one direction only, 1 mark — reference to threshold voltage or very high reverse resistance
Exam Tips: Remember: ammeter in series, voltmeter in parallel — this comes up frequently. | When drawing circuit symbols, make sure you know the difference between a cell (one pair of lines) and a battery (multiple cells). | Ohm's Law only applies to Ohmic conductors at constant temperature — filament lamps and diodes do not obey Ohm's Law. | For thermistor questions: hot = low resistance = high current. Cold = high resistance = low current. | For LDR questions: bright light = low resistance = high current. Dark = high resistance = low current. | When explaining a filament lamp graph, always mention increasing resistance due to increasing temperature . | Current is the same in all parts of a series cir
Common Errors: Watch Out! 1. Wrong: Current is "used up" as it goes around a circuit Correct: Current is the same everywhere in a series circuit — energy is transferred, not charge 2. Wrong: Voltage flows through a circuit Correct: Current flows; voltage (potential difference) is measured across a component — it is the energy per unit charge 3. Wrong: Resistance is "bad" and wastes energy Correct: Resistance is a property that opposes current; it is essential — without resistance, current would be dangerously high 4. Wrong: Higher resistance means less energy is transferred Correct: Higher resistance means less current flows for a given voltage; the energy transferred per unit charge (V) is set by the supp
AO3 - Reasoning & Interpretation: Analysis and Evaluation A student investigates the I-V characteristics of a component and records the following data: Voltage (V) 0 1 2 3 4 5 6 Current (A) 0 0.10 0.18 0.24 0.28 0.30 0.31 (a) Plot a sketch of the I-V graph and state whether the component is Ohmic or non-Ohmic. Justify your answer. (b) Calculate the resistance of the component at 1 V and at 6 V. Explain why the resistance changes. (c) The student did not allow the component to cool between readings. Explain how this affects the validity of the results and suggest an improvement. Answers: (a) The graph curves and flattens — the component is non-Ohmic because current is not proportional to voltage. (b) At 1 V: R = 1/0.10 = 10 Ω
Stretch & Challenge (Grade 8-9):
- Synoptic links: explain how p5 circuit basics connects to another Combined Science (Trilogy) topic you have studied
- Real-world: research one real-world use or example of p5 circuit basics
- Critical: "What are the limitations of the models used in p5 circuit basics?"
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
- Consolidation: Re-answer any Lesson 3 practice questions answered incorrectly (20 mins)
- Retrieval: Write flashcards for the key terms: Electric current, Potential difference (voltage), Resistance (10 mins)
- Exam practice: One past-paper question on p5 circuit basics from the board websites (15 mins)
- Extension: Explain p5 circuit basics to someone else in your own words (10 mins)