A transformer is a device that is used to transfer electric energy from one circuit to another while at the same time keeping the voltage level largely constant. Such transformers can be classified as power transformers (which operate at high voltage and deliver large power), distribution transformers (used to reduce voltages for consumers), and isolation transformers (to electrically isolate customer equipment). It is essential to understand these types when it comes to selecting the most appropriate transformer since there are critical designs used for various applications in the distribution of power networks.