Transformers Flashcards

All 6 cards in this deck

What are the three main parts of a basic transformer?

A primary coil, a secondary coil, and an iron core.

Why is the core of a transformer made of iron?

Iron is easily magnetised, so it carries the changing magnetic field from the primary coil to the secondary coil.

What are the steps by which a transformer induces a potential difference in the secondary coil?

e.g. an alternating input p.d. of $230\ \text{V}$ across the primary

1. The alternating current in the primary coil produces a changing magnetic field.
2. The iron core carries this changing magnetic field to the secondary coil.
3. The changing field induces an alternating potential difference across the secondary coil.

In a step-up transformer, how do the potential differences and the numbers of turns compare?

$V_s > V_p$, and the secondary coil has more turns than the primary.

In a step-down transformer, how do the potential differences and the numbers of turns compare?

$V_s < V_p$, and the secondary coil has fewer turns than the primary.

True or false? A transformer will step up the potential difference of a battery (dc) supply.

False. A steady dc gives a constant magnetic field, so no potential difference is induced in the secondary coil.