Transformers
- A transformer is a device used to change the value of an alternating voltage or current
- This is achieved using electromagnetic induction
Structure of a Transformer
- A basic transformer consists of:
- A primary coil
- A secondary coil
- An iron core
- Iron is used as the core connecting the two coils because it is easily magnetised by the magnetic field generated from the current in the coils
A transformer consists of a primary coil and a secondary coil connected by an iron core
Electromagnetic Induction in a Transformer
- An alternating current is supplied to the primary coil
- This produces a changing magnetic field around it
- The iron core is easily magnetised, so the changing magnetic field passes through it to the secondary coil
- This changing field cuts through the secondary coil and induces an alternating voltage
- This generates an alternating current that flows into the completed circuit beyond
- Its frequency is the same as that through the primary coil
Examiner Tip
Make sure you are clear on the role of electromagnetic induction in the workings on the transformer and not just how they operate.
