P7__Electromagnetism A transformer consists of 2 coils of wire, a primary and secondary. They are sperate. The are wrapped around an iron core, the primary core is connected to an AC supply. The coil generates a changing magnetic field which is passes through the iron core. When a changing magnetic field passes through the secondary coil it induces a potential difference via the Motor Effect
The ratio of potential difference is the ratio between the number of turns in the wire. If the primary has more turns then the potential difference is greater. So the potential difference is lower at the secondary coil however since power is constant this means that the current must be greater at the secondary coil. This is a Step-down transformer