The differential gain of Op-Amp is 4000 and the value of CMRR is 150. Its output voltage, when the two input voltages are 200 μV and 160 μV respectively, will be 

Concept:

For an op-amp, the output is given by:

Vo = Ad Vd + Ac Vc

Vd is the differential voltage at the input of the Op-Amp, i.e.

V_d = V1 – V2

V_c is the common-mode input of the Op-Amp, i.e.

\({V_c} = \frac{{{V_1} + {V_2}}}{2}\)

Also, the CMRR (Common mode rejection ratio) for a differential amplifier is defined as:

\(CMRR=\frac{A_d}{A_c}\)

Calculation:

Given: A_d = 4000, CMRR = 150

\(150=\frac{4000}{A_c}\)

A_c = 26.66

With V₁ = 200 μV and V₂ = 160 μV:

Vd = V1 – V2 = 40 μV

\({V_c} = \frac{{{200μ} + 160μ}}{2}=180μ V\)

The output voltage for the given Op-Amp will be:

Vo = Ad Vd + Ac Vc

V₀ = (4000)(40μ) + (26.66)(180μ)

V₀ = (160 + 4.8) μV

V0 = 164.8 μV