【单选题】已知 下图( a )所示 单级电压放大电路 的输入电阻 R i =2kΩ ,输出电阻 R o =50kΩ ,开路电压增益 Avo =200 。当输入信号源内阻 R s =1kΩ ,输出负载电阻 R L =10kΩ 时 ,则可确定该电压放大电路的源电压增益Avs 约为____ 。若将两级上述电压放大电路级联, R s 、 R L 不变,如 下图( b )所示,则总的源电压增益 约为 ____ 。正确...
【简答题】A.contentment B.satisfaction C.fun D.luxury
【简答题】将 R 1 =200Ω,R 2 =50Ω的两个电阻串联后加上电压U,测得R 1 上电压 U 1 =4V,则可求得R 2 上的电压 U 2 = V ,总电压 = V 。
【简答题】A.abundance B.comfort C.frugality D.luxury
【单选题】The word “luxury” in paragraph 1 is closest in meaning to ____________.
C.
beautifully set tables
D.
a condition of great comfort
【简答题】The word “luxury” in Paragraph 3 means ______. A.something rare but not pleasant B.something that cannot be imagined C.something expensive but not necessary D.something that can only be enjoyed by boy...
【单选题】以下关于柴油机和汽油机相比的说法中,不正确的是( )。
A.
柴油机为外部形成混合气,而汽油机则是内部形成混合气
D.
柴油机低速时扭矩较大,而汽油机高速时扭矩较大
【判断题】luxury means very cheap thing .()
【简答题】如下 图所示电路中,已知C=0.5 μF,R1=100 Ω,R2=50 kΩ,E =200 V。当电容器充电至200 V,将开关S由接点1转向接点2,求初始电流、时间常数及接通后经多长时间电容器电压降至74 V。