24. 有一差動放大器,其兩輸入電壓分別為Vi1 = 55 μV,Vi2 = 45 μV,共模拒斥比CMRR(dB) = 40 dB ,差模增益 Ad = 500,則下列何者正確?
(A)共模增益AC = 10
(B)差模輸入電壓Vd = 5 μV
(C)共模輸入電壓VC = 100 μV
(D)輸出電壓Vo = 5.25 mV
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統計: A(3), B(18), C(13), D(182), E(0) #1639592
統計: A(3), B(18), C(13), D(182), E(0) #1639592
詳解 (共 2 筆)
#2741282
差模輸入電壓Vd=Vi1-Vi2=55u-45u=10uVn
共模輸入電壓Vcm=(Vi1+Vi2)/2=(55u+45u)/2=50uV
共模拒斥比CMRR=40dB=102=100,故共模增益
Vo=Vd*Ad+Vcm*Ac=10u*500+50u*5=5000u+250u=5250uV=5.25mV
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