How do transformers utilise electromagnetic induction?

Transformers utilise electromagnetic induction by transferring electrical energy between two or more circuits through a magnetic field.

In more detail, a transformer is a device that uses the principle of electromagnetic induction to increase or decrease the voltage of an alternating current (AC). It consists of two or more coils of wire wrapped around a common iron core. These coils are known as the primary coil (input) and the secondary coil (output).

When an alternating current is passed through the primary coil, it creates a changing magnetic field around the coil. This changing magnetic field then induces a voltage in the secondary coil. This is the basic principle of electromagnetic induction, as discovered by Michael Faraday. The amount of voltage induced in the secondary coil depends on the ratio of the number of turns in the primary coil to the number of turns in the secondary coil, known as the turns ratio.

If the secondary coil has more turns than the primary coil, the transformer is called a step-up transformer, as it increases the voltage. Conversely, if the secondary coil has fewer turns, it's a step-down transformer, reducing the voltage. This is known as transformer action.

It's important to note that transformers only work with alternating current, not direct current. This is because the changing magnetic field, which is necessary for electromagnetic induction, is only produced by an alternating current.

In addition to voltage transformation, transformers also provide electrical isolation, which can prevent electrical shock and equipment damage. They are a crucial component in many electrical systems, including power grids, audio systems, and electronic devices.

In summary, transformers utilise electromagnetic induction by creating a changing magnetic field with an alternating current in the primary coil, which then induces a voltage in the secondary coil. The voltage can be increased or decreased depending on the turns ratio of the coils.