An electrical system comprises a module (3), an immovable element (2) defining a space for receiving the module and an ejecting mechanism assembled between the immovable element and the module. The ejecting mechanism comprises a guiding frame (6), a groove frame (5) and a first spring element (7) for urging the module to withdraw out of the immovable element. The guiding frame comprises a swing element (63) being rotatable around a pivot pin thereof and a second spring element (62) attached to the swing element. The swing element defines a guiding pin and a balance line. The groove frame defines a continuous groove for guiding the guiding pin. The second spring clement can prevent the guiding pin from being moved along a direction opposite to a predetermined direction.