说明：  开关电源不同于线性电源，开关电源利用的切换晶体管多半是在全开模式(饱和区)及全闭模式(截止区)之间切换，这两个模式都有低耗散的特点，切换之间的转换会有较高的耗散，但时间很短，因此比较节省能源，产生废热较少。
(Switching power supply is different from linear power supply. Switching transistors used in switching power supply mostly switch between fully open mode (saturation zone) and fully closed mode (cut-off zone). These two modes have the characteristics of low dissipation. Switching between the two modes will have a higher dissipation, but the time is very short, so it saves energy and produces less waste heat.)