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 describes the principles of mutual induction that transformers use. The document then discusses core and shell type construction designs. It defines step-up and step-down transformers and provides examples of other transformer types like auto and poly-phase transformers. The bulk of the presentation focuses on instrument transformers, specifically current transformers (CTs) and potential transformers (PTs). It provides details on their construction, operating principles, uses in measurement and protection applications, and important considerations when using them.