Auto transformers only have a single winding and an input and output circuit. Common to both circuits, the winding has at least three electrical connection points known as taps. The voltage source and the load are both connected to two of the taps. One tap at the end of the winding serves as a common connection to the source and the load circuits.
Other types of auto transformers include step down transformer, step up transformer and zig zag transformer. Winshine has the capability to design and manufacturer auto transformer as per your specific needs.