| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Physics |
| Lesson Topic: Describe the construction of a simple transformer with a soft-iron core, as used for voltage transformations |
Learning Objective/s:
- Describe the main components and construction steps of a simple transformer with a soft‑iron core.
- Explain how the turn ratio determines the voltage transformation using Faraday’s law.
- Identify the purpose of insulation and lamination in minimizing losses.
- Apply the construction sequence to sketch a cross‑section diagram of the transformer.
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Materials Needed:
- Projector or interactive whiteboard
- Printed handouts of transformer diagram and construction steps
- Sample soft‑iron laminated core (or image)
- Enamel‑coated copper wire (sample)
- Insulating tape or varnish sample
- Terminal leads and clamps
- Worksheet with turn‑ratio calculations
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Introduction:
Begin with a quick demonstration of a small transformer lighting a bulb to capture interest. Recall that changing magnetic flux induces voltage, a concept explored in previous lessons on electromagnetic induction. Today students will construct a simple transformer and articulate how its design achieves voltage transformation, meeting the success criteria of describing components, explaining the turn‑ratio relationship, and identifying loss‑reduction measures.
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Lesson Structure:
- Do‑now (5') – Students answer a short question on why soft iron is used in transformer cores; teacher checks responses.
- Mini‑lecture (10') – Review key components and the principle of electromagnetic induction using a projected diagram.
- Guided construction walkthrough (15') – Demonstrate each construction step (core stacking, primary winding, insulation, secondary winding, securing, casing) while students label a worksheet.
- Hands‑on activity (20') – In small groups, students assemble a mock‑up or create a detailed sketch, then calculate turn ratios for given voltages.
- Concept check (5') – Quick Kahoot quiz on voltage‑turn ratio and loss mitigation.
- Summary discussion (5') – Groups share findings; teacher clarifies misconceptions.
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Conclusion:
Recap the construction sequence and how the turn ratio sets the output voltage, emphasizing the role of lamination and insulation in efficiency. Students complete an exit ticket stating one key design consideration for minimizing losses. For homework, they solve a problem calculating primary and secondary turns for a specified voltage change.
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