Lesson Plan

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Lesson Plan
Grade: Year 12 Date: 01/12/2025
Subject: Physics
Lesson Topic: understand the principle of a potential divider circuit
Learning Objective/s:
  • Describe the principle of a potential divider and how it creates a fraction of the source voltage.
  • Derive the voltage divider formula for a two‑resistor series circuit.
  • Calculate resistor values to obtain a required output voltage.
  • Analyse the effect of connecting a load and propose ways to minimise loading.
  • Evaluate practical considerations such as resistor tolerance, power dissipation and buffering.
Materials Needed:
  • Projector or interactive whiteboard
  • Printed worksheet with divider problems
  • Breadboard and resistors (1 kΩ, 2.2 kΩ, 5 kΩ, etc.)
  • Multimeter
  • Calculator
  • Optional: Op‑amp for buffering demonstration
 Introduction:
Begin with a quick demonstration of a dimmer switch controlling a lamp, asking students how the brightness changes with resistance. Recall Ohm’s law and series circuits from previous lessons. Explain that today they will learn how a simple resistor network can produce a predictable fraction of a voltage, and they will be able to design one to meet a target output.
Lesson Structure:
  1. Do‑now (5'): Students answer a short question on voltage division from the worksheet.
  2. Mini‑lecture (10'): Explain the divider principle and derive the formula on the board.
  3. Guided derivation (10'): Walk through step‑by‑step derivation using KVL and Ohm’s law.
  4. Hands‑on activity (15'): Build a two‑resistor divider on a breadboard, measure Vout with a multimeter, compare to calculations.
  5. Loading demonstration (10'): Add a load resistor, discuss the voltage change and how to minimise it (buffering).
  6. Practice problems (10'): Students solve two design questions individually while the teacher circulates.
  7. Check for understanding (5'): Quick quiz or exit ticket with one calculation.
Conclusion:
Summarise that the output voltage of a divider is set by the resistor ratio and can be altered by loading. Ask students to write the divider formula and one tip for reducing load effects on their exit ticket. Assign homework to design a 3.3 V divider from a 9 V supply using standard resistor values.