高二物理競賽課件運(yùn)算電路電阻性網(wǎng)絡(luò)各種解法的適用性

運(yùn)算電路，電阻性網(wǎng)絡(luò)各種解法的適用性

15SU3(S)=(5S+0.1)U1–0.1U2–2S·=–18+18S15

–0.1U1+(5S+0.1)U2–3S·=–18+18S15U1(S)=150S+7.5S(25S+1)U2(S)=S(25S+1)225S+7.5I(S)=0.1[U1(S)–U2(S)]==(25S+1)–7.5–0.3(S+)125i(t)=￡–1(t>0)解法：節(jié)點(diǎn)分析+–9S6S12S13S12S13S6S9S+–+–+–+–15S123I(S)10運(yùn)算電路，電阻性網(wǎng)絡(luò)各種解法的適用性u(píng)1(0-)=15=9V

35u2(0-)=6V

UOC(S)=–+=–

9S6S3S例(見教材習(xí)題7-8)+–15V152F2F3F3Fi––++u2u1+–9S6S12S13S12S13S6S9S+–+–+–+–15S10I(S)解法一、應(yīng)用戴維南定理+–9S6S12S13S12S13S6S9S+–+–+–+–15S–+U0Ci(t)=–0.04t–10I(S)+3S25S–13S12SZ0(S)=2=·13S12S+25S12S13S12S13SUOC(S)=–

3S+–9S6S12S13S12S13S6S9S+–+–+–+–15S10I(S)I(S)==

–=

–

3S–25S10+1550S+2312510(S+)討論:是網(wǎng)絡(luò)函數(shù)的一般定義對(duì)正弦穩(wěn)態(tài)電路中定義的網(wǎng)絡(luò)函數(shù)如何理解(2)討論網(wǎng)絡(luò)函數(shù)的意義H(S)與h(t)的關(guān)系網(wǎng)絡(luò)或系統(tǒng)的穩(wěn)定性與對(duì)應(yīng)正弦穩(wěn)態(tài)響應(yīng)的關(guān)系7網(wǎng)絡(luò)函數(shù)7定義與分類零狀態(tài)響應(yīng)的拉氏變換輸入的拉氏變換網(wǎng)絡(luò)函數(shù)H(S)=H(S)H(j)H

(j)=UR.U.+-U.RjC1jL+-UR.+-RSC1SL+-U(S)UR(S)H

(S)=UR(S)U(S)RR+SL+

SC1=jCRR+jL+

1=與對(duì)應(yīng)正弦穩(wěn)態(tài)響應(yīng)的關(guān)系H(S)H(j)

￡[u2(t)]

￡[iS(t)]S1S+212(–)S1S+24H(S)===u2(t)=14.1sin(2t–45o)7網(wǎng)絡(luò)函數(shù)7定義與分類

例

N0為線性定常松弛網(wǎng)絡(luò)。在端口1施加電流源iS(t)=1(t)A

時(shí)，端口2電壓的零狀態(tài)響應(yīng)為u2(t)=21(t)(1–e–2t

)V。

如果將電流源波形改為iS(t)=10sin2tA，求穩(wěn)態(tài)響應(yīng)u2(t)。+iS(t)N0Ru2(t)–11′2′2U2=H(j2)IS=10=14.1–45o

2+j24??2、網(wǎng)絡(luò)函數(shù)的分類(1)策（驅(qū)）動(dòng)點(diǎn)函數(shù)—輸入和輸出在同一端口（或支路）Zin(S)=U1(S)I1(S)Yin(S)=I1(S)U1(S)(分別具有阻抗導(dǎo)納的量綱)Zin(S)=1/Yin(S)+N0Z2(S)U2(S)–I1(S)I2(S)+–U1(S)7網(wǎng)絡(luò)函數(shù)7定義與分類HV(S)=U2(S)U1(S)(轉(zhuǎn)移電壓比)HI(S)=I1(S)I2(S)(轉(zhuǎn)移電流比)(2)傳輸(傳遞、轉(zhuǎn)移)函數(shù)—輸入和輸出不在同一端口（或支路）Z21(S)=U2(S)I1(S)(轉(zhuǎn)移阻抗)Y21(S)=U1(S)I2(S)(轉(zhuǎn)移導(dǎo)納)2、網(wǎng)絡(luò)函數(shù)的分類+N0Z2(S)U2(S)–I1(S)I2(S)+–U1(S)7網(wǎng)絡(luò)函數(shù)7定義與分類7

網(wǎng)絡(luò)函數(shù)的確定121R(+2SC)U1–Ui=012R=SCU2U12R1R(2SC+)U2–SCU0=0H(S)==U0(S)Ui(S)4R2C2S21

例求如圖所示電路的傳遞函數(shù)H(S)=，并求對(duì)應(yīng)的沖激響應(yīng)。U0(S)Ui(S)u0ui-+2CR2R2RCC2SC1SC1SC1Ui(S)U0(S)h(t)=￡–1[H(S)]=t1(t)14R2C2Zin=11Yin=112-13Z21=Y21=11Z212-13HV=1112-13Z2HI=12-137

網(wǎng)絡(luò)函數(shù)的確定+N0Z2(S)U2(S)–I1(S)I2(S)+–U1(S)231Yn(S)E(S)=InS(S)InS(S)=I1(S)00T???E1(S)=I1(S)11E2(S)=I1(S)12E3(S)=I1(S)13網(wǎng)絡(luò)函數(shù)是復(fù)頻率變量S的實(shí)系數(shù)有理函數(shù)H(S)=F1(S)F2(S)(S–zi)i=1m(S–pj)j=1n=H0網(wǎng)絡(luò)函數(shù)的零點(diǎn)和極點(diǎn)Zin=11Yin=112-13Z21=Y21=