"Tiny Cooling Fan" copper conductor cross-sectional area determines the wiring resistance (signal loss caused by the resistance of the digital circuit midline negligible), copper conductors, and thermal conductivity of the insulating substrate temperature impact, thereby determining the ampacity. Is a graph of the ordinary copper clad FR-4 board copper conductor pattern width and cross-sectional area and promised to current. "Tiny Cooling Fan" cross-sectional area of the conductor pattern certainly, when it agreed to the current value 2A, the temperature rise is below 10 ℃, for 35 Um copper, its width should be designed to 2mm: For 70um copper, its width should be designed to lmm. It follows: When the cross-sectional area "Tiny Cooling Fan" conductor agreed on certain current and temperature rise, it can be to meet the cooling requirements of trace copper by increasing the thickness or width greater value in two ways.