Transformers are devices used to either increase or decrease the voltage in a circuit. They are primarily used in electrical applications where the output voltage needs to be different than the input voltage. For example, they can be used to step up or step down voltages in order to match the necessary input or output of a particular device. Transformers can come in a variety of sizes, form factors, and power ratings to meet the requirements of whatever application they’re being used for. Additionally, they can be either step-up or step-down transformers, meaning they can increase or decrease voltage by a fixed amount.