"Tiny Cooling Fan" need to have static and dynamic pressure. Full hydrostatic and hydrodynamic pressure is the algebraic sum of the total pressure is the difference between the total pressure of the fan given the increased amount of the total pressure, the fan between exports and imports. In practice, the nominal value of the maximum wind not blowing fan heat sink to get the actual amount of wind capacity, not on behalf of the ventilation ability. Due to air flow, air flow in its path will encounter obstruct fan heat protracted pieces or elements will limit the free flow of air, that is when "Tiny Cooling Fan" to increase the amount of wind, air pressure decreases. Therefore, there must be an optimum operating point operations, namely the intersection of fan performance curve and drag the curve. At the operating point, the slope of the characteristic curve of the fan to a minimum, change the system characteristic curve was the lowest. Note "Tiny Cooling Fan" static efficiency at this time (the amount of wind power ÷ × pressure) is the best. Of course, sometimes in order to reduce the system impedance, and even choose a smaller size fan, you can also get the same amount of wind.