通过研究单电子晶体管在电路中的静电能量的变化 ,得到了它的阻塞、导通情况与其两端偏压和控制栅压之间的关系 ,从而给出了它的通断图 .并且发现单电子晶体管的对外特性主要由其对外的总电容决定 ;而单电子岛两个隧道结电容的不同主要反映在通断图上由隧道结电容所决定的晶体管阻塞、导通边界线上 ,这两条边界线同时也与外电路有关 By studying the variation of the electrostatic energy in a circuit of a single electron transistor, the relation between the blockage and conduction of the single electron transistor and the bias voltage at both ends and the control gate voltage is given, and its on-off diagram is given. The external characteristics of the electronic transistor are mainly determined by its total external capacitance. The differences between the junction capacitance of two tunnels in a single electronic island are mainly reflected in the on-off diagram of the transistor blocked by the junction capacitance of the tunnel. The boundary of the strip is also related to the outer circuit