For the first example, a maximum case temperature of 95°C will be used with an ambient temperature of 25ºC and a power dissipation of 100 watts. These values result in 0.75 degrees C per Watt thermal resistance. When this value is applied to the chart with natural convection, a heatsink of approximately 105 cubic inches would be required. Only 20 cubic inches would be needed when forced air is applied.