试卷四参考答案
一、1.
fH1?10kHzfHz?100kHz Avm?50dB?10000
Av?10000(1?j/fH1)(1?jf/fH2)
f2、(1)IBQRb?VBE?(1??)IBQ?(Re1?Re2)?VEE
IBQ?VEE?VBERb?(1??)(Re1?Re2)
ICQ??IBQ
VCEQ?(VCC?VEE)?IC(RC?Re1?Re2) (2)
+ rbe υi Rb Re1 – ib ic ?ib Rc + RL υo –
(3) Ri?Rb//[rbe?(1??)Re1]
RO?RC
A????RC//RLrbe?(1??)Re1
RiRi?RS
A?S?A??VCE?0饱和截止 增加Re2阻值
(4) VCE?24V(5)饱和失真(6)改善低频?fL??增大C1,C2,C3的容量 二、
1. T1组成第一级共射电路
T2组成第二级共集电路
T3组成恒流源,作T2的射极电阻
2. Aυ=A?1?A?2
VB1?R23.3?VCC??12V?2.98VR1?R210?3.3VB1?VBE?1.48mAR4?R5rbe1?200?(1??)26?1.078k?IE1IC1?IE1?VB3?R71.8?12?VCC??2.16VR6?R78.2?1.8VB3?VBE?1.46mAR8rbe3?rbe2?200?(1??)26?1.09Ak?IE2
IC2?IC3?IE3?Ri2?rbe2?(1??)RL?51k?AV1??AV2
?R3//Ri2349(3.3//51)????50.09rbe1?(1??)R41.078?50?0.043(1??)RL50?1?1???0.98?AV??49rbe2?(1??)RL1.09?50?1
Ri?R1//R2//[rbe1?(1??)R4]?10//3.3//3.228?1.4k?r?R3RO?be2?87.8?1??
Avd?三、
Vo50?(5.6//1)??????1.15RWvs10?1.8?50?0.5Rs?rbe?(1??)2
?RC//RM2vo?100?A?2k??0.2Vvs? 四、 1.
Vom?13V
VOm2132PO???10.6W2RL2?182VCCVomV2om215?13132PT?(?)?(?)?4.95WRL?48?4voAd?0.2?174mV1.15
2. 应引入电压串联负反馈,电路如下图所示
??PO?68%PO?PT
3.
Avf?VOR?1?1VIR2
五、
1. A1电路为电流串联负反馈 A2电路为电压串联负反馈 2.
IR2?ViR2??R??R1?VVi2??IR21iR2VO?(1?R4RR)Vi2??1?(1?4)ViR3R2R3
六、
1.电压串联负反馈 2.
vi?R1?v02?v02R?5R6
Rv?vO??O5R5?vO??5v02??5(6vi)?30vi
3.
v02??
七、
AV?1?f?1.2.
Rf?3R1R?RfR1?2Rf?2R1?40K
12?RC11??15.9?16(K?)2?cf2??0.1?10?6?100
3.替换R1
V01?VP2?4.
11?2V??(?6V)?1V?3V22?Vth1?4VVth2??2V
八、1.直流电路 滤波 2. 调器管 比较放大 3. 提供基准电压
4.
5.
VA?(1.1~1.2)V2?16.5~18VVD?6VVC?6VVB?VO?9.6V
VCE1?VA?VO?6.9V~8.4V
滑动点位于最上端 滑动点位于最下端
VO?8V VO?12V
VO调节范围8V~12V
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