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IGCSE · Cambridge (CIE) · 0625

Describe a simple two-winding transformer

Identify separate insulated primary and secondary windings linked by a shared soft-iron core.

Transformer and transmission pathway · 4.5.6

Core and Extended; Physics 0625, 2026–2028. Use the stated source, operating conditions and meter ranges. Written practice is self-checked.

Before you begin

  • Trace input and load loops.
  • Distinguish a coil from its core.

Work on paper. Try each question before revealing help, and explain why your method works.

Quick readiness check

Which winding connects to the input source?

What you will learn

  • Identify separate insulated primary and secondary windings linked by a shared soft-iron core.
  • Label a separate-winding soft-iron construction and preserve the electrical-path and operating limits.
Original simple two-winding schematic has separate insulated primary and secondary loops on a shared soft-iron core. The a.c. input and resistive output are shown as separate circuits. Construction does not establish safe ratings, output power or actual efficiency. Winding symbols do not represent literal turn counts.Simple two-winding transformerPrimarySecondary~RShared soft-iron coreSeparate insulated circuitsPrimary: input · secondary: outputConstruction is not rated approvalSymbolic coils · use labelled turns
Original simple two-winding schematic has separate insulated primary and secondary loops on a shared soft-iron core. The a.c. input and resistive output are shown as separate circuits. Construction does not establish safe ratings, output power or actual efficiency. Winding symbols do not represent literal turn counts.

Name the shared core and separate paths

A simple transformer has two insulated wire coils wound around a shared soft-iron core. The primary winding connects to the input source; the secondary winding connects to the output circuit. The core links the two windings magnetically while the wire insulation keeps their conducting paths separate in this stated two-winding design.

Soft iron supports the changing magnetic condition used by the transformer. A closed core path helps link the windings. Do not draw the primary and secondary as one continuous wire or claim that source charge must cross the core into the output coil. This is a simple two-winding transformer, not every possible transformer arrangement.

Keep construction and operating claims separate

The usual voltage-transforming use requires a changing input, normally a.c. in this simple school model. The detailed induction explanation belongs to the Supplement sequence. Merely drawing two coils does not establish output voltage, power, safe ratings or full efficiency.

Treat the diagram as a labelled functional construction, not a mains-wiring procedure. Real insulation, heating, core design and ratings require appropriate specifications. Written identification does not certify practical assembly or safe operation.

Pause and explain

Must electric charge pass directly from primary wire through the core into secondary wire?

Put the idea to work

Worked example

Label the source-connected winding, load-connected winding and shared material in a simple transformer.

Show the worked solution
  1. The source connects to the primary.
  2. The load connects to the secondary.
  3. The common magnetic path is a soft-iron core.

Answer Primary input, secondary output, shared soft-iron core.

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Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.

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From guided practice to a new situation

Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.

1 · Guided

Draw a labelled simple transformer construction.

Give me a hint

Identify two conducting loops and one common magnetic path.

Compare my reasoning
  1. Draw separate primary and secondary coils.
  2. Place them on a shared soft-iron core.
  3. Label input and output connections with insulation kept explicit.

Two insulated windings on a shared soft-iron core.

Look for these in your work

  • Label both winding roles.
  • Separate electrical and magnetic paths.
2 · Independent

A diagram joins both windings into one uninsulated source-to-load wire. Why is that not the stated two-winding construction?

Give me a hint

Check the separate circuit boundaries.

Compare my reasoning
  1. The specified windings are separate conducting paths.
  2. The shared core provides magnetic linking.
  3. A direct wire joins electrical paths instead.

The drawing removes the stated two-winding electrical separation.

Look for these in your work

  • Name the two circuits.
  • Explain the core role.
3 · Transfer

A two-coil sketch has no material, insulation or ratings. Can it certify a safe mains transformer? Explain.

Give me a hint

Construction labels and safety specifications are different evidence.

Compare my reasoning
  1. The sketch does not establish the core or insulation specification.
  2. Heating and voltage/current ratings are missing.
  3. A conceptual diagram is not safe-operation certification.

No: the construction and operating specifications are incomplete.

Look for these in your work

  • Identify missing specifications.
  • Keep written analysis distinct from assembly.

Common mistakes

  • Keep winding circuits separate.
  • Use the given input/output roles.
  • Do not infer safe ratings from a sketch.
Recall without your notes

What can you explain now?

What joins the two windings magnetically in this model?

Compare with the explanation

The soft-iron core

The shared core provides magnetic linking between the separate insulated winding circuits.

After trying it yourself, choose your next review. This is your self-assessment.

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Make it stick

Label a separate-winding soft-iron construction and preserve the electrical-path and operating limits.

If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.

Keep learning Physics

Course scope and assessment

491 sequenced Physics lessons provide 1473 guided, independent and application problems. 58 of 58 syllabus sections have full linked teaching sequences; 0 sections remain pending. Three earlier starter overviews remain available but are not counted as full sequences. The map covers all six subject areas for 2026–2028 and keeps review and assessment limits visible. This is available content, not full programme completion, an exam grade or certified mastery. Written practice is self-checked. Supervised practical experience, cumulative assessment and human subject-teacher review remain pending. Paper method exercises do not demonstrate practical competence or complete either practical-assessment route.

StudyForA · Learn with understanding

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