This presentation discusses different types of transformers used in electrical systems. It begins by defining a transformer as a static device that converts alternating voltages to different voltages while keeping frequency the same. It then explains the principles of mutual induction that transformers use. The presentation covers the main types of transformer constructions and describes step-up and step-down transformers. It provides details on instrument transformers like current transformers and potential transformers, explaining their construction, operating principles, and uses in isolating measurement equipment from high system voltages.