In one embodiment, a heat dissipating apparatus includes a chassis positionable within a housing of a downhole tool. The heat dissipating apparatus also includes a heat sink coupled to the chassis and a displacement mechanism coupled to the heat sink. The displacement mechanism is actuatable to move the heat sink, with respect to the chassis, between a first position and a second position such that in the first position the heat sink is radially retracted toward the chassis to form a gap between the heat sink and the housing and such that in the second position the heat sink is radially extended from the chassis to contact the housing.