GATE EE 2022 Set 1 — Question 36
Go beyond PYQs with Success TrackerAI-powered personalised practice and doubt support. Unlimited practice on eligible plans; AI usage limits apply.MCQ+2 / -0.67HardOp-Amp Non-IdealitiesOperational AmplifiersAnalog & Digital Electronics
Analog & Digital Electronics → Operational Amplifiers → Op-Amp Non-Idealities
Last updated
Question
The output impedance of a non-ideal operational amplifier is denoted by . The variation in the magnitude of with increasing frequency, f, in the circuit shown below, is best represented by
Correct answer
(C) [figure]
Solution
The closed-loop output impedance of an operational amplifier with negative feedback is given by:
For the given voltage follower circuit, the feedback factor . Thus, .The open-loop gain of a typical op-amp has a low-pass characteristic, where it is high and constant at low frequencies and decreases at 20 dB/decade after the dominant pole.
For the given voltage follower circuit, the feedback factor . Thus, .The open-loop gain of a typical op-amp has a low-pass characteristic, where it is high and constant at low frequencies and decreases at 20 dB/decade after the dominant pole.
1.At low frequencies, is very large, so is very small and constant.
2.As frequency increases, decreases, which causes to increase linearly on a log-log scale.
3.At very high frequencies, the gain drops below 1 (), and the closed-loop output impedance approaches the open-loop output impedance , which is typically a constant resistive value. This causes the plot to level off.
This behavior is correctly represented in plot (C).Continue learning with Success Tracker
A step still unclear? Work through it with support
Use Success Tracker to ask about the reasoning, then try another GATE EE question to check your understanding.
AI-powered practice· Unlimited practice on eligible plans
- PYQs with solutions
- Attempt available previous-year questions, then compare your reasoning with the worked solution. Coverage varies by stream.
- Practice that adapts
- Choose a topic, work on weaker areas and bookmark questions to revisit. Your attempts feed your progress tracking.
- AI doubt support
- Ask follow-up questions about a step or concept while practising, instead of stopping at the final answer.
Unlimited practice is available on eligible plans. Free practice and AI usage have limits; check the current plan allowances before choosing.
This page stays readable without an account. AI responses can be wrong; check them against the solution and source material.
More questions on Operational Amplifiers
2026 Set 1 Q33In the linear regulator circuit shown, the base to emitter voltage of the BJT is…2026 Set 1 Q37In the circuit shown, the open loop gain of the operational amplifier is . What is the…2026 Set 1 Q45The digital circuit shown has 3 inputs (, , and ). The simplified logical expression for…2026 Set 1 Q46The MOSFET switches shown in the circuit are ideal. [figure] Which of the following is the correct…2026 Set 1 Q61Consider the circuit shown. Assume that the diode () is ideal. Given …