模拟电子技术第4章习题答案 下载本文

b1ib1c1e2ib2rbe2?2ib2c2b3ib3rbe3e3R6c3viR1R2 rbe1e1?1ib1R4?3ib3vob2

(3) Ri3?rbe3?(1??3)R6

Ri2?Av??rbe2 1??2vo??1Ri2?2R4//Ri3(1??3)R6 ?virbe1rbe2Ri3??1?2(1??3)R4R6

(1??2)rbe1[R4?rbe3?(1??3)R6]Ri=R1//R2//rbe1

R?rRo=R6//4be3

1??34.36阻容耦合放大电路如图题4.36所示。已知VCC=12V,Rb1=Rb2=500k?,Rc1=Rc2

=3k?,晶体管T1、T2特性相同,且?1=?2=29,rbb’1=rbb’2=300?,VBE1=VBE2=0.7V,耦合电容C1、C2、C3的电容量均足够大。试计算:

(1)静态工作电流和电压:IBQ1、ICQ1、VCEQ1、IBQ2、ICQ2、VCEQ2; (2)电压放大倍数Av?vovi,输入电阻Ri和输出电阻Ro。

+VCC Rb1C1TviRiRo1Rc1C2 Rb2Rc2TC32vo

图题4.36

解:

(1) IBQ1?IBQ2?VCC?VBE?22.6?A RbICQ1?ICQ2??IBQ?0.66mA VCEQ1?VCEQ2?VCC?ICRc?10.02V

(2) rbe1?rbe2?rbb???1???26?1.5k?

IEQAv1?vo1?Rc1//Rb2//rbe2???19.3 virbe1Av2?

vo2?Rc2???58 vi2rbe2

Av?vo?Av1Av2?1120 viRi=Rb1//rbe1 ? rbe1=1.5k? Ro=Rc2=3k?

4.37两级阻容耦合放大电路如图题4.37所示。设T1的IDSS=1mA,gm=1mS,T2的?=30,rbb’=300?,VBE=0.7V,设电容器对交流信号均可视为短路。试估算:

(1)T1、T2的静态工作点:IDQ、VDSQ、IBQ、ICQ、VCEQ; (2)电压放大倍数Av?vovi、输入电阻Ri和输出电阻Ro。

Rd6.2k?Rb147k?C2 C1T1Rc5.1k?TRe1100?Re21.8k?2+VCC (+12V)C3viRg3.3M?RiRb213k?RL6.8k?CeRovo

图题4.37

解:

(1)VGS1=0V,所以, IDQ?IDSS?1mA

VDSQ?VCC?IDQRd?5.8V

VB2?VCCRb2?2.6V

Rb1?Rb2VB?VBE?1mA

Re1?Re2ICQ1???33μA

ICQ?IEQ?IBQ?VCEQ?VCC?ICQ(Rc?Re1?Re2)?5V

(2) rbe1?rbb??(1??)26?1.1k? IEQAv1 ??gm?Rd//Rb1//Rb2//?rbe??1???Re1????2

Av2????Rc//RL???20.8 rbe??1???Re1Av?Av1?Av2?42

Ri?Rg?3.3M?

Ro?Rc?5.1k?