Patent ID: 8058962

Claim:
A center-tapped transformer comprising: a spool having a surrounding wall that defines a spool axis, and a partition plate unit that extends in radial outward directions from said surrounding wall so as to divide said spool into axially extending first and second spool parts; a first primary winding unit surrounding said first spool part and passing through a pair of notches to surround second spool part ; and first and second secondary winding units disposed on one side of said first primary winding unit and surrounding said first and second spool parts, respectively; wherein said partition plate unit has first and second partition plate portions that cooperate with said surrounding wall to define said pair of notches, whereby adjusting the thickness of said first and second partition plate portions adjusts leakage inductance of said first primary winding unit; wherein each of said first and second partition plate portions has an end that has a thickness smaller than the remaining parts of a respective one of said first and second partition plate portions to ensure that said first primary winding unit can pass through said notches smoothly.