Patent ID: 7477027

Claim:
An apparatus for use with a computer, comprising: a power source; a system board, coupled to the power source and disposed within the computer, on which an electrical component, which controls operations of the computer, is installed; a heat sink including a plurality of heat transfer surfaces which are configured to contact the electrical component and to thereby remove heat from the electrical component; a fan reversing control card coupled to the system board and configured to generate normal and reverse cycle rotation signals in predetermined intervals, the fan reversing control card including: a counter configured to allow the fan reversing control card to determine when to instruct the fan to switch between the normal and reverse cycles, and, when the fan is to switch from the normal to the reverse cycle, to issue a pulse width modulation (PWM) signal with zero volts, and firmware, disposed within the fan and configured to receive and to interpret the PWM signal, which initiates the reverse cycle when the PWM signal has zero volts; and a fan coupled to the fan reversing control card and configured to receive the normal and reverse cycle rotation signals and to thereby operate in normal and reverse cycles in which the fan rotates in first and second directions, respectively, the fan being disposed within the computer sufficiently proximate to the heat transfer surfaces such that the first and second directional rotations of the fan generate air flows in first and second directions with respect to the heat transfer surfaces, respectively.