Describe a simple two-winding transformer
Identify separate insulated primary and secondary windings linked by a shared soft-iron core.
Section P4.6.3 · Transformers
Cross-referenced from the related Cambridge IGCSE Chemistry 0620 or Physics 0625 teaching to the 0652 syllabus. Exact 0652 Core/Supplement objective coverage and this final-series course’s examiner fit still need specialist review. Written practice is self-checked and does not predict a Cambridge grade or demonstrate supervised laboratory competence.
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.
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.
Sources for this lesson
Pause and explain
Must electric charge pass directly from primary wire through the core into secondary wire?
Worked example
Label the source-connected winding, load-connected winding and shared material in a simple transformer.
Show the worked solution
- The source connects to the primary.
- The load connects to the secondary.
- The common magnetic path is a soft-iron core.
Answer Primary input, secondary output, shared soft-iron core.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →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.
Draw a labelled simple transformer construction.
Give me a hint
Identify two conducting loops and one common magnetic path.
Compare my reasoning
- Draw separate primary and secondary coils.
- Place them on a shared soft-iron core.
- 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.
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
- The specified windings are separate conducting paths.
- The shared core provides magnetic linking.
- 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.
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
- The sketch does not establish the core or insulation specification.
- Heating and voltage/current ratings are missing.
- 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.
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.