一道简单的运算放大器题目？ 模拟电路:关于运算放大器的一道题目,有图
\u4e00\u9053\u7406\u60f3\u7684\u96c6\u6210\u8fd0\u653e\u9898\u76ee\u5b83\u4eec\u7684\u8fd0\u7b97\u5173\u7cfb\uff1a U0=-12Ui
\u5206\u6790\u8fc7\u7a0b\uff1a\u5148\u4ece\u7b2c\u4e00\u4e2a\u8fd0\u653e\u770b\uff0c\u5b83\u662f\u4e00\u4e2a\u540c\u76f8\u8fd0\u7b97\u653e\u5927\u5668\u3002\u5b83\u7684\u8fd0\u7b97\u5173\u7cfbU01=(1+R3/R1)Ui;
\u7b2c\u4e8c\u4e2a\u8fd0\u653e\uff0c\u5b83\u662f\u4e00\u4e2a\u53cd\u76f8\u8fd0\u7b97\u653e\u5927\u5668\u3002 \u5b83\u7684\u8fd0\u7b97\u5173\u7cfbU0=-(R5/R4)U01
\u628a\u7b2c\u4e00\u4e2a\u5f0f\u5b50\u4ee3\u5165\u7b2c\u4e8c\u5f0f\u5b50\uff0c\u6700\u540e\u5b83\u603b\u7684\u8fd0\u7b97\u5173\u7cfb\u5c31\u662f U0=-12Ui \u5e0c\u671b\u5bf9\u4f60\u6709\u5e2e\u52a9\u3002
\u865a\u77ed\u3001\u865a\u65ad\u7684\u6982\u5ff5
\u865a\u77ed\uff1a\u56e0\u4e3a\u7406\u60f3\u8fd0\u653e\u5f00\u73af\u589e\u76ca\uff1aAv\u2192\u221e\u2192\u865a\u77ed\uff0c\u6839\u636e\u8f93\u5165\u8f93\u51fa\u5173\u7cfb\uff0c\u5f97\u5230\uff1a
v \u2248v \uff08\u540c\u76f8\u7aef\u548c\u53cd\u76f8\u7aef\u7535\u4f4d\u8fd1\u4f3c\u76f8\u7b49\uff09\u3002
\u865a\u65ad\uff1a\u7531\u4e8e\u540c\u76f8\u548c\u53cd\u76f8\u4e24\u8f93\u5165\u7aef\u4e4b\u95f4\u51fa\u73b0\u865a\u77ed\u73b0\u8c61\uff0c\u800c\u8f93\u5165\u7535\u963b\uff1aRi\u2192\u221e\u2192\u865a\u65ad\uff0ci=i \u22480 (\u540c\u76f8\u7aef\u548c\u53cd\u76f8\u7aef\u7535\u6d41\u8fd1\u4f3c\u4e3a\u96f6)\u3002
\u8f93\u51fa\u7535\u963b\uff1aRo\u21920
\u8fd0\u653e\u7684\u8f93\u5165\u7535\u963b\uff1aRi\u2192\u221e\u2192\u865a\u65ad\uff0c\u6240\u4ee5R\u65e0\u6240\u8c13\u7684\uff1b
\u8fd0\u653e\u7684\u540c\u76f8\u7aef\u548c\u53cd\u76f8\u7aef\u7535\u4f4d\u8fd1\u4f3c\u76f8\u7b49\uff0c\u6240\u4ee5+\u7aef\u7535\u538b\u7b49\u4e8eui\u7b49\u4e8e-\u7aef\u7535\u538b\uff0c
\u8fd0\u653e\u7684\u540c\u76f8\u7aef\u548c\u53cd\u76f8\u7aef\u7535\u6d41\u8fd1\u4f3c\u4e3a\u96f6\uff0c\u6240\u4ee510\u6b27\u59c6\u548c100\u6b27\u59c6\u7535\u963b\u7684\u7535\u6d41\u76f8\u7b49\uff1b
\u6240\u4ee5ui/10=(uo-ui)/100,\u5373uo=11ui
\u6240\u4ee5\u7535\u538b\u589e\u76ca=uo/ui=11
答案如图，方法主要是虚短虚断的应用
绛旓細鍗 Uo1 = U * (R1+R2)/R1 = U * (1+R2/R1)瀵逛簬鍙充晶鐨勮繍绠楁斁澶у櫒鏉ヨ锛屾牴鎹弽鐩告敮璺殑鐢垫祦鍙互寰楀埌锛歩3 = (U- - Uo1)/R3 = (Uo2 - U-)/R3 U- = U = (Uo1+Uo2)/2 Uo2 = 2U - Uo1 = U * (2 - 1 - R2/R1) = U * (1-R2/R1)姝ゆ椂鍙互寰楀埌锛歩 = (Uo2 ...
绛旓細1銆丄1鏋勬垚鍙嶇浉姣斾緥鏀惧ぇ鐢佃矾锛孉2鏄姞鍑忔硶鐢佃矾銆2銆佺涓绾ф斁澶х數璺細Uo1=-R2/R1*Ui1=-1.2*Ui1=-1.2V 绗簩绾ч渶瑕佹牴鎹彔鍔犲畾鐞嗗垎姝ヨ绠楋紝鍏堝弽鐩稿悗鍚岀浉锛孶o21=-R5/R4*Uo1=-2.5*(-1.2)=3V銆俇o22=(1+R5/R4)*Ui2*(R7/(R6+R7))=3.5*3*0.5=5.25V Uo2=Uo21+Uo22=8.25V...
绛旓細铏氱煭锛氬洜涓虹悊鎯宠繍鏀惧紑鐜鐩婏細Av鈫掆垶鈫掕櫄鐭紝鏍规嵁杈撳叆杈撳嚭鍏崇郴锛屽緱鍒帮細v 鈮坴 锛堝悓鐩哥鍜屽弽鐩哥鐢典綅杩戜技鐩哥瓑锛夈傝櫄鏂細鐢变簬鍚岀浉鍜屽弽鐩镐袱杈撳叆绔箣闂村嚭鐜拌櫄鐭幇璞★紝鑰岃緭鍏ョ數闃伙細Ri鈫掆垶鈫掕櫄鏂紝i=i 鈮0 (鍚岀浉绔拰鍙嶇浉绔數娴佽繎浼间负闆)銆傝緭鍑虹數闃伙細Ro鈫0 杩愭斁鐨杈撳叆鐢甸樆锛歊i鈫掆垶鈫掕櫄鏂紝鎵浠鏃犳墍...
绛旓細鈥滆櫄鏂濓細鎸囩殑鏄浘涓殑鐢垫祦锛欼1=0銆両2=0銆傗滆櫄鐭濓細鎸囩殑鏄浘涓袱涓妭鐐1銆2鐨勭數浣嶇浉绛夛紝鍗砋1=U2銆傛樉鐒讹細U1=2V銆傛墍浠ワ細U2=2V銆傝杈撳嚭绔疉鐐圭數浣嶄负Uo锛屽洜姝わ細Uo=3i銆傛敞鎰忎笂杩颁腑鐨刄1銆乁2銆乁o閮芥槸鎸囩殑璇ョ偣鐢典綅锛屼篃灏辨槸璇ョ偣涓庡叕鍏卞湴涔嬮棿鐨勭數鍘嬨1惟鐢甸樆鐢垫祦涓猴細锛圲o-U2锛/1=锛3i-2锛...
绛旓細Vo2鍗曠嫭浣滅敤鏃讹紝Vo1鍜孷o3缃负0锛岃岃櫄鐭壒鎬т笅Vn3鍜孷p3閮=0锛孷n3鍜孷o1=0鎯呭喌涓嬪氨娌℃湁Vo2鐨勭數娴佸湪R1涓婃椿鍔紒Vo1鍗曠嫭浣滅敤鏃跺悓鐞嗐
绛旓細杩愭斁姝ｈ礋涓ょ鐨勮緭鍏ョ數鍘嬩负(U+)-(U-)>0,鐢垫祦涓烘媺鐢垫祦銆傛墍浠o1涓烘鐨勩3锛夋瘮杈冨櫒鐨勮緭鍏ヤ负Uo1锛岃緭鍑轰负Vo锛屾瘮杈冪數鍘嬩负5v 鎵浠ヨ繍鏀句负鍙岀數婧愯緭鍑轰负鏈濂姐備笖鐢垫簮鐢靛帇澶т簬5v銆傚綋Uo1>=5v锛孷o=-5v锛堥檺鍘嬶級褰揢o1<5v锛孷o=5v锛堥檺鍘嬶級濡傛灉鏄崟鐢垫簮锛屼笖鐢垫簮鐢靛帇澶т簬5v 褰揢o1>=5v锛孷o=0锛堥檺鍘嬶級褰...
绛旓細/锛圧1+R2鈭3锛=2脳锛2鈭5锛/锛2+2鈭5锛=5/6锛圴锛夈傛墍浠ワ細I3=U/R3=锛5/6锛/5=1/6锛坢A锛夈傚洖鍒板師鍥撅細鏍规嵁鈥滆櫄鏂濓紝鍙嶇浉杈撳叆绔緭鍏ョ數娴佷负闆讹紝鎵浠ワ細I3=If銆侷f=锛圴n-Vo锛/Rf=锛0-Vo锛/2=-Vo/2銆傛墍浠ワ細-Vo/2=1/6锛孷o=-1/3锛圴锛夈傗斺棰樼洰涓殑绛旀閫夐」閮戒笉姝ｇ‘銆
绛旓細杩欐槸涓涓悓鐩告瘮渚杩愮畻鐢佃矾锛屽垎鏋愪笅锛(鍋囪鍥句腑宸﹁竟鐨勪笁涓數鍘嬫爣鍙峰垎鍒负V1锛孷2锛孷3)锛屾牴鎹滆櫄鏂濆緱锛岋紙0-V1锛/R1鈮堬紙V1-V0锛/R2 V1鈮圴3鈮圴0 鎵浠 V0=2+2锛圧2/R1锛=2+2*2=6V
绛旓細杩愭斁杈撳嚭鏈夛細Uo = Au*锛圲p - Un锛夛紱鍥犱负鐞嗘兂杩愭斁锛屽叾澧炵泭鏃犻檺澶э紝浣嗘槸 杈撳嚭鐢靛帇鍗存槸鏈夐檺鐨勶紝鏈澶у煎彧鑳=Vcc锛涙墍浠ワ紱褰 Up - Un >0 鏃讹紝Uo = Vcc锛涘綋 Up - Un <0 鏃讹紝Uo = -Vee锛涘叾涓 Un=Vref=1V
绛旓細鍥炵瓟锛氬亣璁綬1鍜孯S涓棿鐐逛负VI,鐢变簬R1=RS,鍒橵1=(1/2)VS=100mV,VO=-(R2/R1)VI=-10*100mV=-1V(鍙嶇浉姣斾緥鏀惧ぇ鐢佃矾)
