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📘 Electricity 1 – Notes & Revision

📘 Download the Full Booklet (PDF)

Use this page to revise for the Electricity 1 assessment.
Work through each collapsible section below.

🗺️ What this assessment is about

You will be tested on:

  • Circuit symbols and simple circuit diagrams
  • Voltage, current and resistance — meanings, symbols and units
  • Rules for current & voltage in series and parallel circuits
  • Using ohmmeters correctly
  • Using V = I R to solve problems
  • Combining resistors in series and parallel
🔗 Useful Links
📌 Core Facts & Equations
Key Definitions
  • Voltage (V) – the electrical push that gives energy to charges. It is the energy transferred per unit charge (per coulomb). Unit: volt (V).
  • Current (I) – the flow of charge every second. Bigger current means more charge passing a point each second. Unit: ampere (A).
  • Resistance (R) – how much a component opposes the flow of current. High resistance → harder for current to flow. Unit: ohm (Ω).
Essential Equations & Rules
  • V = I × R (Ohm’s Law) – links voltage, current and resistance.
  • Series circuits:
    • Current: same everywhere (only one path).
    • Voltage: splits across components. Bigger resistance → bigger share of the voltage.
    • Resistance: adds up → RT = R₁ + R₂ + …
    • Adding more components increases total resistance → current becomes smaller.
  • Parallel circuits:
    • Voltage: same across every branch.
    • Current: splits into branches and rejoins afterwards. Lower-resistance branches take more current.
    • Resistance: total becomes smaller than the smallest resistor → 1/RT = 1/R₁ + 1/R₂ + …
    • Adding a new branch gives current another path → total current increases.
⚠️ Common Mistakes & How to Fix Them
  • Mixing up voltage and current
    • Voltage = push
    • Current = flow
  • Putting an ammeter in parallel
    • Can damage the meter.
    • Ammeters must be placed in series.
  • Adding resistors in parallel
    • Total resistance always decreases when you add a parallel branch.
  • Reading resistor bands backwards
    • Band 1 and Band 2 are the two stripes nearest the edge.
  • Forgetting units
    • Voltage → V (volts)
    • Current → A (amps)
    • Resistance → Ω (ohms)
  • Using V = I R incorrectly
    • To find I → I = V ÷ R
    • To find R → R = V ÷ I
  • Current in parallel branches
    • Current splits into branches.
    • It joins back together before returning to the supply.
    • A lower-resistance branch takes more current.
  • Thinking bulbs “use up” current
    • Bulbs use energy, not current.
📊 Revision Summary Grid
Voltage
• The push that moves charges
• Measured in volts (V)
• Series: voltage splits
• Parallel: voltage same
• Bigger resistance → bigger voltage drop
Current
• Flow of charge per second
• Measured in amps (A)
• Series: same everywhere
• Parallel: splits then rejoins
• Lower resistance → more current in that branch
Resistance
• Opposition to current
• Measured in ohms (Ω)
• Series: adds
• Parallel: total is less than the smallest resistor
Formulas
• V = I × R
• RT(series) = R₁ + R₂ + …
• 1 / RT(parallel) = 1/R₁ + 1/R₂ + …
• I = V ÷ R  R = V ÷ I
🎬 Electricity 1 Revision Videos
✅ Practice Questions

Class Practice Papers

  • Practice Paper 1 – basic circuit symbols, series/parallel rules.
  • Practice Paper 2 – current division, ohmmeters, V = IR graphs.
  • Challenge Papers – higher difficulty problems.
  • 📝 Electricity 1 Practice Test (PDF)

N5 Practical Electronics Past-Paper Questions (Block 1)

These questions come from the official N5 Practical Electronics PPQ (Nov 2025 Update) , filtered to match the Electricity Block 1 topics:

  • 2017 SQP: Q1a, Q1b, Q3
  • 2018: Q1a, Q1b, Q3
  • 2019: Q1a, Q1b, Q3, Q5b
  • 2024: Q1a, Q1b, Q3, Q7b
  • 2025: Q1a, Q1b, Q2, Q3

These cover all Block 1 outcomes: circuit symbols, colour code, voltage/current rules, resistance calculations, series & parallel analysis, and V = IR.

N5 Physics Past-Paper Questions (Block 1)

These questions come from the N5 Physics Past Papers (Sept 2025 Update) , filtered to include only Electricity Block 1 content.

  • 2014: P1 Q1, Q2, Q3; P2 Q1
  • 2015: P1 Q1, Q2, Q3, Q4; P2 Q1
  • 2016: P1 Q1, Q3, Q4; P2 Q1, Q2b, Q3d
  • 2017: P1 Q3, Q4; P2 Q2a(i), Q2b(i)
  • 2018: P1 Q1a(ii), Q1b; P2 Q6a, Q6b, Q9, Q10, Q11
  • 2019: P1 Q1d, Q2a(i), Q2a(iii); P2 Q6a(ii), Q6b(ii)
  • 2020: P1 Q12, Q13; P2 Q6, Q7a, Q7b(i), Q7b(ii)
  • 2022: P1 Q6, Q7, Q12, Q13, Q14, Q6c
  • 2023: P1 Q11, Q12, Q13, Q16
  • 2024: P1 Q11, Q12, Q13, Q7c, Q6d, Q8, Q11a, Q12
  • 2025: P1 Q11, Q12, Q5; P2 Q6, Q7c, Q7a, Q7c

These questions match the exact S3 assessment content: circuit symbols, voltage/current rules, series & parallel circuits, resistance calculations, and V = IR.

📝 Self-Check: Success Criteria (L1–L6)

L1

  • I can draw the circuit symbol for: cell, battery, lamp, switch, voltmeter, ammeter, motor, microphone, loudspeaker, photovoltaic cell.
  • I can define potential difference (voltage).
  • I can define current.
  • I can describe practical applications of series and parallel circuits.

L2

  • I can measure current and voltage correctly using appropriate meters.
  • I can apply current and voltage rules in series circuits.
  • I can apply current and voltage rules in parallel circuits.
  • I can describe the symbol, function and application of resistors and variable resistors.

L3

  • I can use an ohmmeter to measure resistance.
  • I can use resistor colour coding.
  • I can make V-I measurements in simple and complex circuits.
  • I can determine resistance from a V-I graph.
  • I can use the correct relationship to calculate V, I and R.

L4

  • I can describe how temperature affects resistance of a conductor.
  • I can describe how temperature affects resistance of a resistor.
  • I can describe an experiment to prove Ohm’s Law.
  • I know what happens to total resistance when components change in series and parallel circuits.
  • I can predict and measure total resistance in a series circuit.

L5

  • I can predict the total resistance in a parallel circuit (equal resistors).
  • I can measure total resistance in a parallel circuit (equal resistors).
  • I can predict and measure total resistance in a series circuit.

L6

  • I can predict the total resistance in a parallel circuit with equal resistors.
  • I can measure total resistance in a parallel circuit with equal resistors.
🧠 AI Tutor – Electricity Block 1 Revision

Use our class AI tutor to revise Electricity Block 1. Click the button below to launch the tutor with the correct S3 Physics settings.

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⚙️ Interactive Tools

🔧 Interactive Simulation – Circuit Construction Kit (DC)

Use the simulation to build circuits, add meters, and experiment safely.

🎨 Resistor Colour Code Calculator

Select the colours of the 4 bands to calculate the resistor value.

Value:

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⚡ V = I R Practice Generator

Click “New Question” to generate a random V, I or R calculation.

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