what is single phase auto transformer?

A single-phase autotransformer is a type of electrical transformer that uses a single winding to serve as both the primary and secondary coils. This design allows for voltage transformation with fewer materials and a smaller footprint compared to traditional transformers. The winding is tapped at various points to provide different voltage levels. Autotransformers are commonly used in applications like voltage regulation and motor starting due to their efficiency and compact size.