Electronic Devices - Operational Amplifiers - Discussion
Discussion Forum : Operational Amplifiers - General Questions (Q.No. 72)
72.
At what input voltage level does the output voltage level become numerically equal to the value of the common-mode gain of the amplifier?
Discussion:
2 comments Page 1 of 1.
Sarika rajesh said:
1 decade ago
Gain A = vo/vi.
vo = A(Vi1-vi2).
= A(0.5-(-0.5)).
Vo = A(1).
Therefore Vout is equal to gain.
vo = A(Vi1-vi2).
= A(0.5-(-0.5)).
Vo = A(1).
Therefore Vout is equal to gain.
Millize said:
4 years ago
Output Voltage at common mode operation is given by:
Vo = AdVd +AcVc.
Ad = Differential Gain.
Ac = Common Mode Gain.
Vc = Common mode voltage = V1+V2/2.
Vd = Differential Voltage = V1-V2.
Substituting;
Vo = Ad(V1-V2) + Ac(V1+V2/2).
V1 = 0.5 & V2 = -0.5 then,
Vo = Ad(0.5+0.5) + Ac(0/2).
Vo= Ad.
Vo = AdVd +AcVc.
Ad = Differential Gain.
Ac = Common Mode Gain.
Vc = Common mode voltage = V1+V2/2.
Vd = Differential Voltage = V1-V2.
Substituting;
Vo = Ad(V1-V2) + Ac(V1+V2/2).
V1 = 0.5 & V2 = -0.5 then,
Vo = Ad(0.5+0.5) + Ac(0/2).
Vo= Ad.
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