Abstract: A foldable transformer includes an enclosure (10), a plug assembly (12), and a locating assembly (14). The enclosure has a storage cavity (16) at a top end thereof. A window (20) is defined in the enclosure in communication with a bottom portion of the storage cavity, for receiving the plug assembly therethrough. The plug assembly includes a pair of inserting pins (34), a rotatable rod (36) having an arched profile, a pair of metal ears (38), and a pair spring pins (44). Each inserting pin is made of conductive material, is insert-molded in the rod, and electrically connects with a corresponding ear. The locating assembly includes a pair of slots (48) for receiving the spring pins, and a cam (56) for resiliently engaging with the plug assembly so that the plug assembly can be disengagably fixed in a folded position or an unfolded position.