| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Physics |
| Lesson Topic: explain the use of four diodes (bridge rectifier) for the full-wave rectification of an alternating current |
Learning Objective/s:
- Describe the function of each diode in a bridge rectifier during both half‑cycles.
- Explain how a bridge rectifier produces a full‑wave rectified output and its effect on ripple frequency.
- Calculate the DC output voltage and ripple voltage for a given bridge‑rectifier circuit.
- Compare the advantages of a bridge rectifier with half‑wave and centre‑tapped designs.
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Materials Needed:
- Projector or interactive whiteboard
- Slide deck showing bridge diagram and waveforms
- Breadboard, four diodes (e.g., 1N4007), AC source/transformer, load resistor, filter capacitor
- Multimeter or oscilloscope
- Worksheet with calculation problems
- Calculator
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Introduction:
Begin with a quick poll: “What happens to the negative half of an AC signal in a simple diode circuit?” Connect this to students’ prior work on half‑wave rectification and state that by the end of the lesson they will be able to design and analyse a bridge rectifier that uses both halves of the AC waveform.
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Lesson Structure:
- Do‑now (5'): Students answer short questions on half‑wave vs full‑wave rectification on a sticky‑note board.
- Mini‑lecture (10'): Present the bridge configuration, diode orientation, and waveform transformation using slides.
- Guided demonstration (15'): Build the bridge on a breadboard; show current flow for the positive half‑cycle, then the negative half‑cycle, measuring the output with a multimeter.
- Calculation activity (10'): In pairs, students compute VDC and Vripple from the provided component values and complete the worksheet.
- Concept check (5'): Quick Kahoot quiz covering diode biasing, ripple frequency, and advantages of the bridge.
- Summary & reflection (5'): Teacher recaps key ideas; each student writes one “take‑away” sentence on an exit ticket.
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Conclusion:
Review how the bridge rectifier converts both halves of the AC cycle into a unidirectional output and how the ripple can be reduced with a filter capacitor. Collect exit tickets as a formative check, and assign a homework problem set that asks students to design a bridge rectifier for a 12 V DC supply using different load resistances.
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