Step-up transformers are used for increasing voltage. A transformer is a device that transfers electrical energy between two or more circuits through electromagnetic induction. It consists of a primary coil and a secondary coil, which are wound around a shared core.

When the primary coil is connected to an alternating current (AC) power source, it creates a changing magnetic field. This changing magnetic field induces a current in the secondary coil, which is connected to the load.

A step-up transformer has more turns in the secondary coil than the primary coil. Therefore, when the voltage is applied to the primary coil, the resulting induced voltage in the secondary coil is higher than the input voltage. This allows the transformer to increase the voltage level.

Step-up transformers are commonly used in power transmission systems to increase the voltage of electrical energy for efficient long-distance transmission. Higher voltage can minimize energy losses in the transmission lines. Additionally, these transformers can be found in various applications such as electrical power distribution, voltage regulation, and in some electronic devices that require higher voltage.