Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Physics
Lesson Topic: Quantum physics
Learning Objective/s:
  • Describe the quantum‑mechanical origin of diode forward conduction and reverse blocking.
  • Explain how diode parameters (V_F, I_R, V_BR) affect rectifier performance.
  • Calculate the required smoothing capacitor value for a given load and ripple specification.
  • Analyse ripple voltage and ripple factor to assess the quality of a smoothed DC supply.
Materials Needed:
  • Projector or interactive whiteboard
  • Power supply and mains transformer (50 Hz)
  • Diodes (silicon, ≥40 V rating)
  • Electrolytic capacitor (≈22 000 µF, ≥35 V)
  • Multimeter or oscilloscope
  • Worksheet with example calculation
  • Simulation software (e.g., PhET or LTspice)
 Introduction:
Begin with a quick video clip showing a flashlight turning on when a battery is connected, prompting students to recall how diodes allow current one way. Ask them what they know about “steady” versus “pulsating” DC and set the success criteria: students will link quantum concepts to practical rectifier design and perform a smoothing calculation.
Lesson Structure:
  1. Do‑Now (5'): Students list everyday devices that use DC power and note any that might need smoothing.
  2. Mini‑lecture (10'): Quantum basis of rectification – band theory, carrier tunnelling, Shockley equation.
  3. Demonstration (15'): Build a full‑wave bridge with the diodes and capacitor; display waveform before and after smoothing on the oscilloscope.
  4. Guided calculation (15'): Walk through the example design for a 12 V RMS supply, highlighting each formula.
  5. Worksheet activity (10'): Pairs calculate capacitor size for a new set of specifications (e.g., 24 V RMS, 0.3 A load, r ≤ 0.03).
  6. Check for understanding (5'): Quick quiz via clicker/hand‑raise on key parameters (V_F, PIV, ripple factor).
  7. Summary (5'): Recap quantum‑mechanical origins and practical implications.
Conclusion:
Students summarise how quantum behaviour of the p‑n junction determines diode performance and how a capacitor mitigates ripple. An exit ticket asks them to write one sentence linking the band‑gap concept to the ripple reduction formula. For homework, assign a short problem set designing smoothing circuits for different load currents and frequencies.