Edexcel IGCSE Physics · Spec 6.8-6.9
Transformers
How transformers change the voltage of an alternating supply.
Physics revision video
Transformers
Prefer to watch on YouTube? Open this video on YouTube.
Spec 6.8-6.9
What you need to know
- Describe how a transformer works
- Tell step-up and step-down transformers apart
- Explain their use in the National Grid
Active recall
Quick check
Answer each question before opening the answer.
What does a transformer do, and why must it use a.c.?
It changes the size of an alternating voltage; it needs a changing (a.c.) current so the magnetic field keeps changing and induces a voltage.
What is the difference between a step-up and a step-down transformer?
Step-up increases the voltage (more turns on the secondary); step-down decreases it (fewer turns on the secondary).
Physics video companion
Keep your notes and exam practice together
The free Physics workbook follows every video in specification order.