Exam-style question
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Which of the following is a limitation of real operational amplifiers?.
- A.Limited bandwidth
- B.Infinite input impedance
- C.Zero output resistance
- D.No offset voltage
Model answer
What a good answer should say
- Limited bandwidth
Explanation
Why this works
Rule: Gain‑bandwidth product (GBP) is constant for an op‑amp. Substitution: A_ol × f_3dB = GBP.
Working: For a typical op‑amp, A_ol ≈ 10^5 and f_3dB ≈ 10 kHz, so GBP ≈ 10^9. Answer: Limited bandwidth.
Units: Hz. Conclusion: Real op‑amps cannot amplify signals beyond their bandwidth.
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