Patent ID: 8692638

Claim:
A transformer comprising: a bobbin including at least one partition wall formed on an outer peripheral surface of a pipe shaped body part thereof; a plurality of coils wound and stacked on the body part; and a core electromagnetically coupled to the coils to thereby form a magnetic path, wherein the respective coils are disposed in a plurality of spaces partitioned by the at least one partition wall, wherein the bobbin includes a terminal connection part extended from any one end of the body part in an outer diameter direction thereof and including a plurality of external connection terminals connected to an end thereof, wherein the terminal connection part includes at least one lead groove formed therein, and at least one of the coils has a lead wire led to the outside of the bobbin through the at least one lead groove, wherein the lead groove is formed by cutting a portion of the terminal connection part so that the outer peripheral surface of the body part is exposed, wherein the terminal connection part includes an extension groove in a portion of the lead groove adjacent to the body part, the extension groove formed by extending a width of the lead groove, and wherein one of the coils has a lead wire disposed in a changed direction while supporting a sidewall of the extension groove.