习题2-13 在图P2-13的放大电路中,设三极管的β=100,UBEQ=-0.2V,rbb’=200?。①估算静态时的IBQ,ICQ和UCEQ;②计算三极管的rbe值;③求出中频时的电压放大倍数;④若输入正弦电压,输出电压波形为,试问三极管产生了截止失真还是饱和失真?应该调整电路中的哪个参数(增大还是减少)?-VCCRVCC?UBEQb-10V解:①IBQ??20?A490k?RcC2Rb3k?C1IEQ?ICQ??IBQ?2mA++?URLo?UCEQ?VCC?(?ICQRc)??4VUi_3k?_②rbe?rbb??(1??)③2626?200?101??1.5k?IEQ2????(Rc//RL)??100④是截止失真,应减少RAubrbe习题2-14 在图P2-14的电路中,设β=50,UBEQ=0.6V。①求静态工作点;②画出放大电路的微变等效电路;③求电压放大倍数、输入电阻和输出电阻。+VCC解:①VCC?IBQRb?UBEQ?(1??)IBQRe+12VRbRc470k?C2VCC?UBEQ12?0.73.9k??IBQ???20?AC1Rb?(1??)Re470?51?2+RL?ReIEQ?ICQ??IBQ?1mAUi2k?3.9k?_UCEQ?VCC?ICQRc?IEQRe?6.1V②微变等效电路26?1.63k?③rbe?300?(1??)IEQ????(Rc//RL)??0.94Aurbe?(1??)ReRi?Rb//??rbe??1???Re???84.9k?+?Uo_?UirbeRb??IbRLReRc?UoRo?Rc?3.9k?
习题2-15 设图P2-15中三极管的β=100, UBEQ=0.6V,rbb’=100?, VCC=10V, Rc=3k?, Re=1.8k?, RF=200?, Rb1=33k?, Rb2=100k?, 负载电阻RL=3k?,电容C1、C2、C3均足够大。①求静态工作点;②画出微变等效电路;③求电压放大倍数Au;④设RS=4k?,求AuS;+VCC⑤求Ri和Ro。Rb2Rb1Rc解:①UBQ?VCC?2.48VC2Rb1?Rb2C1ICQ?IEQ?UBQ?UBEQRF?Re?0.94mARs+Re+IBQ?ICQ??9.4?A?+UiRb1?Us--RFRLCe?Uo-UCEQ?VCC?ICQRc?IEQ?RF?Re??5.3V②微变等效电路Rb?Rb1//Rb2+U?i?RbUs--26?2.89k?IEQRs+rbe?R?IbLRFRc?Uo③rbe?rbb??(1??)Au???(Rc//RL)??6.5rbe?(1??)RF④Ri?Rb1//Rb2//??rbe??1???RF???11.96k?Aus?RiAu??4.87Ri?RsRo?Rc?3k?
习题2-16 P106解:①VCC?IBQRb?UBEQ?(1??)IBQRe?IBQ?VCC?UBEQRb?(1??)Re?10?ARbC1+VCCC2ReRL+IEQ?ICQ??IBQ?1mAUCEQ?VCC?IEQRe?6.4V②rbe?300?(1??)?Ui-+?-Uo26?2.93k?IEQ??RL=∞时,Au?1???Rerbe?(1??)Re?0.99?0.97??RL=1.2k?时,Au?1???Re//RLrbe?(1??)Re////RL③RL=∞时,Ri?Rb//??rbe??1???Re???283k?RL=1.2k?时,Ri?Rb//??rbe??1????Re//RL????87.6k?④?rbe?Rs??rbeRo??//R??29??e1??1????
习题2-17 P107RbC1+Rc?U?Rco1???Urbe?(1??)Rei?U(1??)Reo2??Ur?(1??)Ribee+VCCC2C3ReRL?Ui-?Uo1?Uo2???U?当Rc=Re时,Uo1o2uituo1tuo2t+?UiRbrbeRe??Ib+?Uo1-+R?Uo2c--VCC=15VRb1=2.5k?RCRb2=10k?Rb2??UUoiReRLRc=3k?RL=3k?Rb1VCC解:①β=50CbU?UBEQRb1UBEQ=0.6VUBQ?VCC?3VRe?BQ?1.2k?Rb1?Rb2IEQrbb’=300?IBQ?ICQ??0.04mA?40?AI=2mA②ICQ?IEQ?2mAEQUCEQ?VCC?ICQRc?IEQRe?6.6V26???(Rc//RL)?77.8?963?③rbe?rbb??(1??)AuIEQrberbeRi??18.8?Ro?Rc?3k?1??习题2-18 P107C1C2
习题2-19 P107解:(a)共基电路(b)共射电路(c)共集电路(d)共射电路(e)共射-共基电路习题2-20 P107Rd4iD/mA3VDD2105101520RguI+uO?iDuGS=3V2V1.5V1VuDS/VQ+-VGG-解:①直流负载线方程:uDS?VDD?iDRd?20?5.1iDUGSQ?2V,UDSQ?8.3V,IDQ?2.3mA?iDg??1.7mS②m?uGSRo?Rd?5.1k?③Au??gmRd??8.7VDD=20VVGG=2VRd=5.1k?Rg=10M?