What is an Auto Transformer?Auto Transformer DefinitionAn auto transformer is defined as a type of electrical transformer with a single winding acting as both the primary and secondary winding.Single Winding TheoryAn auto transformer uses a single winding for both the primary and secondary purposes, unlike two-winding transformers which use separate windings. The diagram below illustrates this concept.The winding AB of total turns N1 is considered as primary winding. This winding is tapped from