【摘要】 介绍了电子电路中常采用的单元电路———电流源的组成、工作原理以及描述电流源性能指标的定量计算及电流源主要组成形式———电流镜和微电流源， 分析了这两类电路的工作特点． 由于电流源直流电阻很小和交流电阻很大， 其作为有源负载被广泛应用在共射极放大器、共集电极放大器和差动放大器中， 以达到改善这些放大器性能的目的．更多还原

【Abstract】 As an unique unit circuit,current source takes an important role in electronics.First,the construction and the working principle of unit circuit?current source which used in electronic circuit and the ration calculation describing function target of current source are introduced.Then,the major form of current source?current mirror and small?value current source are described,and the characteristics for this two circuits are analyzed in detail.Finally,for the characteristics of the small DC resistance and large AC resistance,as an active load,the current source is widely used in common collector,common emitter and differential amplifier to improve the function target of amplifier.更多还原