Brainlag PlusTwo coils on an iron core: how a transformer works, step-up and step-down, the turns ratio Vp/Vs = np/ns and power in = power out for an ideal transformer.
Two coils, one core
- An alternating current in the primary coil makes a changing magnetic field
- The iron core carries that changing field through the secondary coil
- The changing field induces an alternating p.d. across the secondary coil
There is no wire between the coils: the energy passes through the changing field. A steady d.c. makes a steady field, which induces nothing, so a transformer only works with a.c.
The rest of this lesson and its 9 practice questions are in Plus.
Screen 1 of 5, free to read.
- 9 exam-style questions, marked as you go, each with a worked solution
- The Scientific Calculator beside every question
- Anything you get wrong is saved to your flashcards