autotransformer

[ aw-toh-trans-fawr-mer ]
/ ˌɔ toʊ trænsˈfɔr mər /

noun Electricity.

a transformer having a single coil that serves as both a primary coil and a secondary coil.

Origin of autotransformer

First recorded in 1890–95; auto-1 + transformer

British Dictionary definitions for autotransformer

autotransformer
/ (ˌɔːtəʊtrænsˈfɔːmə) /

noun

a transformer in which part of the winding is common to both primary and secondary circuits