Because "220V AC Cooling Fan" in the resin sheet poor thermal conductivity, while copper lines and holes are good conductor of heat, and therefore the rate of progress and increase the thermal conductivity of copper foil remaining holes are the primary means of cooling. Evaluation "220V AC Cooling Fan" PCB cooling capacity, it is necessary to the thermal conductivity of the composite material by a variety of different materials in each PCB calculated using the equivalent thermal conductivity of the insulating substrate (nine eq). Equivalent thermal conductivity "220V AC Cooling Fan" PCB board as shown in Figure 6. The smaller thickness, the thicker foil, the higher the rate of copper surplus, the more layers, the greater the equivalent thermal conductivity, PCB board lead (bulk) heat better.