A transformer is an electrical device that changes the potential difference (voltage) of an alternating current supply.
A basic transformer consists of two coils of wire, which are not connected. These coils are wrapped around an iron core.
1. An alternating current is supplied to the primary coil.
2. The current flows through the primary coil and produces a magnetic field.
3. The iron core is easily magnetised, so the changing magnetic field passes through it.
4. As a result, the changing magnetic field induces a potential difference in the secondary coil.
5. If the secondary coil is part of a complete circuit, then alternating current will flow.
Transformers do not work with direct current (DC) as the magnetic field produced by DC does not change.
Transformers are used: