i really want to know how an Auto transformer works , most simplest form if possibe thnx

 

The Wikipedia entry is pretty good. They're basically a single inductor with center taps. They're often used with automatic tap changers for line voltage regulation and in industry as a lighter, non-isolated alternative to a traditional Xfmr. I've used them to bump voltages up from 240V, 400V and 480V to 600V for an mobile industrial application.

 

Hello,

Here is a link to a PDF on autotransformers:
http://nptel.iitm.ac.in/courses/IIT-MADRAS/Electrical_Machines_I/pdfs/1_11.pdf

Bertus