Summary Topic 7 - Magnetism and Electromagnetism

Transformers change the size of the pd of an alternating
current

They all have two coils of wire, the primary and the
secondary, joined with an iron core

Alternating current in primary coil causes continuously
changing magnetic fluc in the core

When an alternating pd is applied across the primary cooil,
the iron core magnetises and demagnetises quickly

The change in magnetic field induces and alternating pd in
the secondary coil

If the second coil is part of a complete circuit, this causes a
current to be induced

Ratio between the primary and secondary pd is the same as
the ratio between the number of turns on the primary and
secondary coils

Step up transformers -have more turns on the primary coil Transformers
that the secondary coil Topic
Step down transformers - they have more turns on the pimary
coil than the secondary