【单选题】改进型的镜像电流源电路如图所示。已知图中的三个晶体管特性均相同,且【图片】足够大,UBE=0.7V,V1=V2=10V,R2=4.7k【图片】,为使该电流源正常工作,试问电阻R1的阻值选择有无限制?【图片】
【单选题】The movie Jurassic Park was a big hit, with its novel idea ___________ a mixture of fear and excitement into people’s hearts.
【单选题】油品液面高度3m以下,在液面高度 测一点油温。
【简答题】晶体管电路如下图所示,已知E=12V,Uce=6V,Ube=0.7V,R=4.7kΩ,RRP=5kΩ(接入有效电阻为2kΩ),REL=30Ω,试确定电路中各点电位;计算各元件两端电压和流过电流;晶体管的放大倍数。(计算结果保留2位有效数字)
【单选题】以下关于飞经走气法说法错误的是( )
C.
本法是在遍运五经穴后,左手四指自曲池轮流弹跳至总筋,操作9次,再以拇、食二指拿阴池、阳池两穴不动,最后再用右手握患儿四指做屈伸动作20次,左右摆动20次
D.
《小儿推拿方脉活婴秘旨全书》曰:“飞经走气法:化痰动气。先运五经穴;后做此法。用五指关张,一滚,一笃,做至关中,用手打拍乃行也。”
【单选题】The popularity of films such as Jurassic Park, in which a scientist clones several kinds of extinct dinosaurs, proves how the idea a mixture of fear and excitement into people’s hearts.
【简答题】已知 如图 所示电路中,晶体管 β =100 , =1.4kΩ 。 (1) 现已测得静态管压降 U CEQ =6V ,估算 R b ; (2) 若测得 和 的有效值分别为 1 mV 和 100 mV ,则负载电阻 R L 为多少?
【单选题】The popularity of films such as Jurassic Park, a scientist clones several kinds of extinct dinosaurs, proves how the idea struck a mixture of fear and excitement into people’s hearts.
【单选题】若患者同时符合多动症和品行障碍的临床表现,应诊断为()