On hearing the great news that Beijing has won the birds of 2008 Olympic Games, The crowds at Tian An Men Square began to cheer ______________. (excited)
【简答题】电路如图8-19所示,已知稳压管的稳定电压U Z =6V,晶体管的U BE =0.7V, R 1 =R 2 =R 3 =300Ω,U I =24V。 (1) 说明电路的整流电路、滤波电路、调整管、基准电压电路、比较放大电路、采样电路等部分各由哪些元件组成。 (2) 确定电路输出电压的范围。 (3) 判断出现下列现象时,分别因为电路产生什么故障(即哪个元件开路或短路): ①U O ≈24V; ②U ...