GATE EC 2025 Set 1 — Question 30
Go beyond PYQs with Success TrackerAI-powered personalised practice and doubt support. Unlimited practice on eligible plans; AI usage limits apply.MSQ+1 / -0MediumCS, CD & CG ConfigurationsBJT & MOSFET AmplifiersAnalog Circuits
Analog Circuits → BJT & MOSFET Amplifiers → CS, CD & CG Configurations
Last updated
Question
Which of the following statements is/are TRUE with respect to ideal MOSFET-based DC-coupled single-stage amplifiers having finite load resistors?
Correct answer
(B) The common-source amplifier has an infinite input resistance; (D) The input and output voltages of the common-drain amplifier are in phase
Solution
Analysis of MOSFET amplifier configurations:
- Common-Gate (CG) Amplifier: The input is at the source. The input resistance is approximately , which is finite. (Statement A is FALSE)
- Common-Source (CS) Amplifier: The input is at the gate. For an ideal MOSFET, the gate current is zero, so the input resistance is infinite. (Statement B is TRUE)
- Phase Relationship in CS: The CS amplifier is an inverting amplifier, meaning there is a phase shift between the input and output voltages. They are not in phase. (Statement C is FALSE)
- Phase Relationship in Common-Drain (CD) / Source Follower: The CD amplifier is a non-inverting amplifier with a voltage gain slightly less than 1. The input and output voltages are in phase. (Statement D is TRUE)
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 EC 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 BJT & MOSFET Amplifiers
2026 Set 1 Q17The ideal OP-AMP circuit shown in the Figure produces output voltage when the Switch, S,…2026 Set 1 Q18Consider the circuit shown in the Figure with and . Assume…2026 Set 1 Q50A small signal source, is applied to a BJT circuit as…2026 Set 1 Q53A circuit using an ideal OP-AMP is shown in the Figure. Which of the following options gives the…2026 Set 1 Q60An -channel MOSFET is connected as shown in the Figure. Assume ,…