"Tiny Cooling Fan" PCB board due to resistive heating circuit itself, as well as exchanges, high-frequency heat intensified. PCB is made of copper conductor and dielectric materials, dielectric material is generally thought that does not heat. Copper conductor patterns due to the inherent resistance of copper, when the current through the period on heat, like mA (milliamps), uA (microampere) level as a small current through the period, "Tiny Cooling Fan" title negligible heat, but large current (one hundred mA and above) by period can not be ignored. It is worth noting that when the temperature rises to about conductor pattern 85 ℃, insulation material itself begin to yellow, current continues through the final copper pattern fuse, especially plywood inner graphics, surrounded by poor heat conductivity resin, cooling difficulties, and thus the temperature rise is inevitable, so particular attention to the design of the conductor pattern width. In fact, "Tiny Cooling Fan" go make PCB layout design line width of the main basis for its heat and thermal environment to determine.