南京邮电大学：《模拟电子技术》课程教学资源（PPT课件讲稿）第九章 部分习题（主讲：杨恒新）

9-1OTL电路如图P9-1所示。已知U=UE=20V,负载R=8,并忽略功率 管导通的饱和压降,试回答: (1)测得负载电压有效值等于10V,电路的输出功率、管耗、直流电源供给的功率以 及能量转换的效率各为多少? (2)管耗最大时,电路的输出功率和效率各为多少? a十 CC C D VVD L 图P9-1

2 U210 1)P1=0=2=125W R L 8 1+U`兀 c2m =2U ch PE=0c兀 CC /2U o c R L R L laU Pe=2Ucc 10√2 =2×20 =2252W TR L 3.14x8

12.5W 8 10 2 2 = = = L o L R U P    cm CC c m EE c m E CC I U I U I P U 2 1 2 =  +  = L o L om cm R U R U I 2  = = 22.52W 3.14 8 10 2 2 20 2 2 =   = =   L o E CC R U P U  (1)

CSE P P 2 2)(22.52-125)=5W PL 2_P_125 Eh225=555% 2 (2)当Um=-Uc时每管的损耗最大 1U14U 1420 P on CC=-× =10.1w 2 R L 2丌2R L 2丌28 元 Z 2 =2=×=50% 4 元

(22.52 12.5) 5W 2 1 2 2 = − = − = E L C P P P 55.5% 22.52 12.5 2 2 = = = = E L E L P P P P  (2) 当 Uom UCC 时每管的损耗最大  2 = 10.1W 8 4 20 2 4 1 2 1 2 1 2 2 2 2 2  = =  =  =  L  CC L o m L R U R U P 50% 2 4 4 = =  =     

9-2上题电路中,在169负载上要求输出功率为8W,试确定下列功率管要求的极 限参数PcM、U(scB及Iw 1U2 ∵P= 01 2R, L ∴Uon=√2PR1=√2×8×16=16V 16 lmn="=:=1A R L 16 UCC=UEE>Uom U(BR)CEO 2UCC : U(BR)CEo > 32V cm(max) =CC>om=Im=1A ICM>I R R cm(max) L L ∴Iom>1A

L om L R U P 2 2 1  = Uom = 2PL RL = 2816 = 16V 1A 16 16 = = = L om cm R U I UCC = UEE  Uom U(BR)CEO  2UCC U(BR)CEO  32V (max) =  = cm = 1A L o m L CC cm I R U R U I  ICM  1A CM cm(max) I  I

P P/ 当Um==UC时 Pmn≈0.2m=0.2xlUc i PI/2 2 RL Uc>U O om/occ 0.641 2 ∴m>0.2×1am =0.2×8=1.6W 2 R L Pu >P CM Cm ∴P>16W

L CC Cm Lm R U P P 2 2 1  0.2 = 0.2 当 Uom UCC 时  2 = UCC  Uom 0.2 8 1.6W 2 1 0.2 2    =  = L o m Cm R U P  PCM  PCm  PCM  1.6W Uom/UCC 0.64 1 PL/2 PE/2 PC P O