Abstract: An apparatus is used for controlling a rotating direction of a fan. The apparatus comprises a power source, a signaling unit, a switching unit, and an activating module. The power source is used for supplying power for the apparatus. The signaling unit is used for generating direction-control signals. The switching unit is connected to the power source and the signaling unit, and used for controlling the switching unit to work. The activating module is connected to the switching unit and the fan, and used for driving the fan to selectively rotate in one of two opposite directions based on the direction-control signals. A method for driving the fan in the two directions is also disclosed.

Abstract: An apparatus is used for controlling a rotating direction of a fan. The apparatus comprises a power source, a signaling unit, a switching unit, and an activating module. The power source is used for supplying power for the apparatus. The signaling unit is used for generating direction-control signals. The switching unit is connected to the power source and the signaling unit, and used for controlling the switching unit to work. The activating module is connected to the switching unit and the fan, and used for driving the fan to selectively rotate in one of two opposite directions based on the direction-control signals. A method for driving the fan in the two directions is also disclosed.

Abstract: A heat sink (20) includes a chassis (23), and a plurality of fins (25) extending upwardly from the chassis. The chassis includes a platform (27) and a guide portion (29) extending horizontally from. an end portion of the platform. The guide portion has top and bottom surfaces. At least one of the top and bottom surfaces is arcuate such that the guide portion tapers toward a distal end. When a fan system operates at a side of the heat sink generally facing the guide portion, the guide portion guides cooling air generated from the fan to top and bottom surfaces of the chassis and to bottom portions of the fins, whereupon the cooling air exits the heat sink. Heat accumulating on the chassis and the bottom portions of the fins is thereby efficiently removed.