電路原理教程第2版課件ch13講稿

第十三章雙口網(wǎng)絡(luò)第十三章雙口網(wǎng)絡(luò)引言1、一端口（單口）網(wǎng)絡(luò)的復(fù)習(xí)二端網(wǎng)絡(luò)端口的概念i

+-+-US(s)U(s)I(s)Z(s)+-U(s)I(s)Y(s)IS(s)I(s)=Y(s)U(s)+-uiNN0U(s)=Z(s)I(s)I(s)=–IS(s)

+Y(s)U(s)U(s)=US(s)

+Z(s)I(s)N2、二端口(雙口)網(wǎng)絡(luò)多端網(wǎng)絡(luò)二端口(雙口)網(wǎng)絡(luò)i2=–i1i4=–i3i1四端網(wǎng)絡(luò)i2i3i41234雙口網(wǎng)絡(luò)11

2

2i1-+u1+-i2u2端口變量參考方向的約定電壓、電流關(guān)系的描述要研究的問題i1+i2+i3+i4=0雙口網(wǎng)絡(luò)對(duì)外部電路的作用或呈現(xiàn)的特性i1，i2u1，u2i1，u2u1，i2u2，i2u1，i1u1，i1u2，i2u1，i2i1，u2u1，u2i1，i2電壓、電流關(guān)系的描述雙口網(wǎng)絡(luò)11

2

2i1-+u1+-i2u22、二端口(雙口)網(wǎng)絡(luò)13-1雙口網(wǎng)絡(luò)的Z、Y、H、T參數(shù)方程討論對(duì)象：線性時(shí)不變松弛雙口網(wǎng)絡(luò)LTI11

2

2I1(s)-+U1(s)+-I2(s)U2(s)N013-1-1Z參數(shù)方程1、方程的導(dǎo)出LTI11

2

2I1(s)-+U1(s)+-I2(s)U2(s)N0LTI11

2

2I1(s)-+U1(s)+-I2(s)U2(s)N013-1-1Z參數(shù)方程1、方程的導(dǎo)出U11(s)=z11(s)I1(s)U21(s)=z21(s)I1(s)U12(s)=z12(s)I2(s)U22(s)=z22(s)I2(s)U1(s)=U11(s)+U12(s)=z11(s)I1(s)+z12(s)I2(s)U2(s)=U21(s)+U22(s)=z21(s)I1(s)+z22(s)I2(s)LTI11

2

2I1(s)-+U11(s)+-U21(s)N0LTI11

2

2-+U12(s)+-I2(s)U22(s)N0+U1

z11

z12U2

z21

z22I1I2=2、參數(shù)的含義U(s)=Z(s)I(s)U1(s)=z11(s)I1(s)+z12(s)I2(s)U2(s)=z21(s)I1(s)+z22(s)I2(s)13-1-1Z參數(shù)方程1、方程的導(dǎo)出LTI11

2

2I1(s)-+U1(s)+-I2(s)U2(s)N0z11=U1I1I2=0端口2-2

開路，端口1-1

的入端阻抗z21=U2I1I2=0端口2-2

開路，正向轉(zhuǎn)移阻抗LTI11

2

2I1(s)+-U2(s)

N0LTI11

2

2-+U1(s)

I2(s)N03、討論（1）如果雙口網(wǎng)絡(luò)滿足互易條件z12=z21z22=U2I2I1=0端口1-1

開路，端口2-2

的入端阻抗z12=U1I2I1=0端口1-1

開路，反向轉(zhuǎn)移阻抗2、參數(shù)的含義（開路阻抗參數(shù)）U1(s)=z11(s)I1(s)+z12(s)I2(s)U2(s)=z21(s)I1(s)+z22(s)I2(s)13-1-1Z參數(shù)方程a)給定雙口網(wǎng)絡(luò)的結(jié)構(gòu)和元件參數(shù)RLC例1（2）如果雙口網(wǎng)絡(luò)關(guān)于中分面對(duì)稱（3）Z參數(shù)的確定z11=z223、討論13-1-1Z參數(shù)方程LTI11

2

2I1(s)-+U1(s)+-I2(s)U2(s)N0OO

z11=U1I1I2=0z21=U2I1I2=0+-RsLsC1+-U1(s)U2(s)I1(s)I2(s)=R+sC1sC1==z12+-RsLsC1+-U1(s)U2(s)I1(s)I2(s)z22=U2I2I1=0=sL+sC1z21=z12sC1=a)給定雙口網(wǎng)絡(luò)的結(jié)構(gòu)和元件參數(shù)（3）Z參數(shù)的確定13-1-1Z參數(shù)方程z11=R+sC1sC1(R+)I1(s)+I2(s)=U1(s)sC1sC1I1(s)+(sL+)I2(s)=U2(s)sC113-1-1Z參數(shù)方程（3）Z參數(shù)的確定a)給定雙口網(wǎng)絡(luò)的結(jié)構(gòu)和元件參數(shù)例2

+-+-++--I1U33U33I2I2U1U21

2

2

令I(lǐng)2=0U1=I1+2I1=3I1z11=3U2=–23U3+U3=–52I1=–10I1z21=–10令I(lǐng)1=0U1=3I2+2I2=5I2z12=5U2=2(I2–3U3)+2I2=–8I2z22=–8例2

+-+-++--I1U33U33I2I2U1U21

2

2

I2I1U1=3I1+3I2+2I2=3I1+5I2U2=2I1+4I2–23U3=–10I1–8I213-1-1Z參數(shù)方程（3）Z參數(shù)的確定a)給定雙口網(wǎng)絡(luò)的結(jié)構(gòu)和元件參數(shù)b)給定特定端接條件b)給定特定端接條件13-1-1Z參數(shù)方程（3）Z參數(shù)的確定。求此雙例3=10oAI1.I1.2=45oAU2.2=10-45oV+-+--+

(10+j5)100oVI2.U2.U1.I1.互易網(wǎng)絡(luò)圖示互易雙口網(wǎng)絡(luò)，已知當(dāng)開關(guān)打開時(shí)，;當(dāng)開關(guān)閉合時(shí),口網(wǎng)絡(luò)的Z參數(shù)。當(dāng)開關(guān)打開時(shí)z11=U1?I1?=100o45o22=5–45oz21=U2?I1?=10–45o45o22=10–90o=z12。求此雙例3=10oAI1.I1.2=45oAU2.2=10-45oV+-+--+

(10+j5)100oVI2.U2.U1.I1.互易網(wǎng)絡(luò)圖示互易雙口網(wǎng)絡(luò)，已知當(dāng)開關(guān)打開時(shí)，;當(dāng)開關(guān)閉合時(shí),口網(wǎng)絡(luò)的Z參數(shù)。z112=5–45oz21=

z12=10–90o100o=25–45o10o+10–90oI2?I2?=0.5135o

2–(10+j5)

=10–90o10o+z22

0.5135o

20.5135o

2

z22=15–90o當(dāng)開關(guān)閉合時(shí)13-1-2Y參數(shù)方程13-1雙口網(wǎng)絡(luò)的Z、Y、H、T參數(shù)方程1、方程的導(dǎo)出LTI11

2

2I1(s)-+U1(s)+-I2(s)U2(s)N0LTI11

2

2I1(s)-+U1(s)+-I2(s)U2(s)N0I1

y11

y12I2

y21

y22U1U2=I1(s)=y11(s)U1(s)+y12(s)U2(s)I2(s)=y21(s)U(s)1+y22(s)U2(s)LTI11

2

2I11(s)-+U1(s)

N0I21(s)LTI11

2

2+-I22(s)U2(s)

N0I12(s)+13-1-2Y參數(shù)方程13-1雙口網(wǎng)絡(luò)的Z、Y、H、T參數(shù)方程2、參數(shù)的含義（短路導(dǎo)納參數(shù)）I1(s)=y11(s)U1(s)+y12(s)U2(s)I2(s)=y21(s)U1(s)+y22(s)U2(s)I1U1U2=0y11=端口2-2

短路，端口1-1

的入端導(dǎo)納I2U1U2=0y21=端口2-2

短路，正向轉(zhuǎn)移導(dǎo)納I2U2U1=0y22=端口1-1

短路，反向轉(zhuǎn)移導(dǎo)納端口1-1

短路，端口2-2

的入端導(dǎo)納I1U2U1=0y12=LTI11

2

2I1(s)-+U1(s)+-I2(s)U2(s)N013-1-2Y參數(shù)方程13-1雙口網(wǎng)絡(luò)的Z、Y、H、T參數(shù)方程（1）如果雙口網(wǎng)絡(luò)滿足互易條件y12=y21（2）如果雙口網(wǎng)絡(luò)為對(duì)稱雙口網(wǎng)絡(luò)y11=y22（3）Y與Z的關(guān)系3、討論LTI11

2

2-+U1(s)

N0I2(s)

LTI11

2

2+-U2(s)

N0I1(s)

I1

y11

y12I2

y21

y22U1U2=U1

z11

z12U2

z21

z22I1I2=Z=detYy22–y12–y21y111Y=detZ

z22–z12–z21

z111（4）Y參數(shù)的確定例1++SLsCR1U1(s)U2(s)I2(s)I1(s)--13-1-2Y參數(shù)方程13-1雙口網(wǎng)絡(luò)的Z、Y、H、T參數(shù)方程3、討論解法一：按參數(shù)定義令U2(s)=0y11=+R1sL1y21=R–1I2=–RU1=y12令U1(s)=0y22=+R1sC例1++sLsCR1U1(s)U2(s)I2(s)I1(s)--解法二：列寫節(jié)點(diǎn)電壓方程（4）Y參數(shù)的確定13-1-2Y參數(shù)方程I1=(+)U1–U2R1sL1R1I2=–U1+(+sC)U2R1R113-1-3H參數(shù)方程13-1雙口網(wǎng)絡(luò)的Z、Y、H、T參數(shù)方程LTI11

2

2I1(s)-+U1(s)+-I2(s)U2(s)N0i1，u2u1

，i2u1

，i2i1，u2U1h11h12I1I2h21h22U2=ub=h11ib+h12ucic=h21ib+h22uc共射極晶體管的輸入-輸出特性+-+-ibubucic13-1-3H參數(shù)方程13-1雙口網(wǎng)絡(luò)的Z、Y、H、T參數(shù)方程U1h11h12I1I2h21h22U2=（混合參數(shù)方程）參數(shù)的含義U1I1U2=0h11=端口2-2

短路，端口1-1

的入端阻抗I2I1U2=0h21=端口2-2

短路，正向電流比I2U2I1=0h22=端口1-1

開路，端口2-2

的入端導(dǎo)納U1U2I1=0h12=端口1-1

開路，反向電壓比LTI11

2

2I1(s)-+U1(s)+-I2(s)U2(s)N02）與基本參數(shù)的關(guān)系3）對(duì)稱雙口網(wǎng)絡(luò)H參數(shù)的特點(diǎn)detH=1討論1）雙口網(wǎng)絡(luò)滿足互易條件時(shí)H參數(shù)的特點(diǎn)h12=–

h2113-1-3H參數(shù)方程（混合參數(shù)方程）LTI11

2

2N0I2(s)

LTI11

2

2+-U2(s)

N0I1(s)

+-U1(s)

U1I1U2=0h11=I2I1U2=0h21=I2U2I1=0h22=U1U2I1=0h12==y111=detZz22y21y11=z22=–z21z221=detYy11=y11=–y12z12z22=13-1雙口網(wǎng)絡(luò)的Z、Y、H、T參數(shù)方程13-1-4T參數(shù)方程（傳輸參數(shù)方程）LTI11

2

2I1(s)-+U1(s)+-I2(s)U2(s)N0u2

，i2u1

，i1u1

，i1u2

，i2U1ABU2I1CD–I2=關(guān)于I2前面的“–”參數(shù)的含義U1ABU2I1CD–I2=參數(shù)的含義U1U2-I2=0A=端口2-2

開路時(shí)的電壓比I1U2-I2=0C=端口2-2

開路時(shí)的轉(zhuǎn)移導(dǎo)納I1-I2U2=0D=端口2-2

短路時(shí)的電流比U1-I2U2=0B=端口2-2

短路時(shí)的轉(zhuǎn)移阻抗例求圖示電路的傳輸參數(shù)。雙口網(wǎng)絡(luò)滿足互易條件時(shí)T參數(shù)的特點(diǎn)對(duì)稱雙口網(wǎng)絡(luò)T參數(shù)的特點(diǎn)與基本參數(shù)的關(guān)系U1=z11I1+z12I2U2=z21I1+z22I213-1-4T參數(shù)方程（傳輸參數(shù)方程）U1ABU2I1CD–I2=detT=AD–BC=z21z21z11z22z21z21z11z22–z12z21–=1A=DI1=U2+[–I2]z211z21z22U1=U2+[–I2]z21z11z21detZsL13-1雙口網(wǎng)絡(luò)的Z、Y、H、T參數(shù)方程sL1sL1sL1sL1––Y=H=sL1–10T=sL11013-2

雙口網(wǎng)絡(luò)的等效電路等效的含義13-2-1

用Z參數(shù)表示的等效電路LTI11

2

2I1(s)-+U1(s)+-I2(s)U2(s)N01、一般情況+-+-+-+-U1(s)U2(s)I1(s)I2(s)z11z12I2(s)z21I1(s)z22U1

(s)=z11I1(s)+z12I2(s)U2

(s)=z21I1(s)+z22I2(s)13-2-1

用Z參數(shù)表示的等效電路LTI11

2

2I1-+U1+-I2U2N01、一般情況U2=z21I1+z22I2=z12[I1+I2]+(z22–z12)I2+(z21–z12)I1U1=z11I1+z12I2=(z11–z12)I1+z12[I1+I2]U2++--z12z11–z12U1I1-+z22–z12(z21–z12)I1I2U2+-++--z12z11–z12z22–z12(z21–z12)I1U1I1I213-2

雙口網(wǎng)絡(luò)的等效電路13-2-1

用Z參數(shù)表示的等效電路1、一般情況LTI11

2

2I1-+U1+-I2U2N02、如果雙口網(wǎng)絡(luò)滿足互易條件，即z12=z2113-2-2用Y參數(shù)表示的等效電路U2++--z12z11–z12z22–z12U1I1I213-2

雙口網(wǎng)絡(luò)的等效電路13-2-3

用H參數(shù)表示的等效電路LTI11

2

2I1-+U1+-I2U2N0U1h11h12I1I2h21h22U2=+-U1I1h11h12U2-+-+U2I2h21I1h22+-+-ibubucich11rbe晶體管輸入電阻h21

晶體管電流放大系數(shù)h22晶體管輸出電導(dǎo)13-3

雙口網(wǎng)絡(luò)的互相連接（復(fù)合雙口網(wǎng)絡(luò)）N3N1N2N4電路設(shè)計(jì)問題電路分析問題13-3-1

雙口網(wǎng)絡(luò)的級(jí)聯(lián)（鏈型連接）1、概念N2??????N1Nn13-3

雙口網(wǎng)絡(luò)的互相連接13-3-1

雙口網(wǎng)絡(luò)的級(jí)聯(lián)（鏈型連接）1、概念N1N2Nn2、參數(shù)關(guān)系T=T1T2???Tn+-+-+-NaNbUa1+-Ib1Ua2Ub2Ub1Ia2Ia1Ib2Ua1Ia1TaUa2–Ia2=TaTb=Ub2–Ib2Z=ZA+ZBNANBIA2IA1IB1IB2

IA1

IA2

IB1

IB2I1I2+-+-UA1+UB1+-UB2+-UA2+--U1U22、參數(shù)關(guān)系U1U2UA1UA2UB1UB2=+13-3-2

雙口網(wǎng)絡(luò)的串聯(lián)如果

IA1=I

A1，IA2=I

A2IB1=I

B1，IB2=I

B2U1U2IA1IA2=ZA+ZBIB1IB2=(ZA+ZB)I1I213-3-2

雙口網(wǎng)絡(luò)的串聯(lián)

3、串聯(lián)的有效性及其判斷Z=ZA+ZB2、參數(shù)關(guān)系（條件：IA1=I

A1，IA2=I

A2，IB1=I

B1，IB2=I

B2）-+UOC.

IA2NANB+-US.IB2IA2IA1I

A1IB1I

B1I

B2NANBIA2IA1IB1IB2

IA1

IA2

IB1

IB2-13-3-2

雙口網(wǎng)絡(luò)的串聯(lián)3、串聯(lián)的有效性及其判斷13-3-3

雙口網(wǎng)絡(luò)的并聯(lián)NANB1、概念例13-3

雙口網(wǎng)絡(luò)的互相連接13-3-3

雙口網(wǎng)絡(luò)的并聯(lián)IA2IA1IB1IB2

IA1

IA2

IB1

IB2I1I2+-+-U1U2NANB2、參數(shù)關(guān)系3、并聯(lián)的有效性及其判斷Y=YA+YB（條件：IA1=I

A1，IA2=I

A2，IB1=I

B1，IB2=I

B2）13-3-3

雙口網(wǎng)絡(luò)的并聯(lián)3、并聯(lián)的有效性及其判斷IA2IB2

IA2

IB2+NANB-US?+-UOC?13-3-4

雙口網(wǎng)絡(luò)的串并聯(lián)H=HA+HB13-4有端接雙口網(wǎng)絡(luò)的分析13-4-1

端口電壓和端口電流的計(jì)算概述U13000.210–3I1I21000.110–3U2=例如圖所示，雙口網(wǎng)絡(luò)N0的H參數(shù)方程為I11k

LTI11

2

2-+U1+-U2N0+-1k

100mVI2其中電阻的單位為，電導(dǎo)的單位為S，求U2。解法一直接解4個(gè)聯(lián)立方程解法二應(yīng)用戴維南定理，先求端口2-2

的等效電路13-4有端接雙口網(wǎng)絡(luò)的分析13-4-1

端口電壓和端口電流的計(jì)算U13000.210–3I1I21000.110–3U2=U1=300I1+0.210–3U2I2=100I1+0.110–3U2U1=0.1–103I1U2=–103I2I11k

LTI11

2

2-+U1+-U2N0+-1k

0.1VI2U2=–7.09VI11k

LTI11

2

2-+U1+-U2OCN0+-0.1VU2OC=–V10001113-4有端接雙口網(wǎng)絡(luò)的分析13-4-1

端口電壓和端口電流的計(jì)算I11k

LTI11

2

2-+U1+-U2N0I2–103I1=300I1+0.210–3U2I2=100I1+0.110–3U2R0==U2I213104

11

U2OC=–V1000112

2+-U2+-1k

U2OCR0U1=300I1+0.210–3U2I2=100I1+0.110–3U2U2=–7.09V13-4有端接雙口網(wǎng)絡(luò)的分析13-4-1

端口電壓和端口電流的計(jì)算13-4-2

輸入阻抗與輸出阻抗I1ZSLTI11

2

2-+U1+-U2N0+-ZLUSIZinZou定義問題：雙口網(wǎng)絡(luò)與外部電路相連接時(shí)，常常要考慮其對(duì)輸入電路的影響和帶負(fù)載的能力Zin=U1I1（獨(dú)立電源置零）Zou=U2I2問題：用哪一個(gè)參數(shù)方程討論比較方便？2、輸出阻抗13-4有端接雙口網(wǎng)絡(luò)的分析13-4-2

輸入阻抗與輸出阻抗I1ZSLTI11

2

2-+U1+-U2N0+-ZLUSI2ZinZou1、輸入阻抗U1=AU2+B(–I2)I1=CU2+D(–I2)Zin=U1I1AZL+BCZL+D=（獨(dú)立電源置零）Zou=U2I2DZS+BCZS+A=13-4

有端接雙口網(wǎng)絡(luò)的分析Z=

5–j5–j10–j10–j15例圖示電路，問ZL為何值時(shí)它可以從電路中獲得最