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GATE 2022 EE – Question 12

Analog and Digital Electronics · Amplifiers: biasing, equivalent circuit and frequency response · 1 mark · Multiple choice

For an ideal MOSFET biased in saturation, the magnitude of the small signal current gain for a common drain amplifier is

  1. 0
  2. 1
  3. 100
  4. infinite

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Show answer and explanation

Correct answer: (D) infinite

Explanation

The gate of an ideal MOSFET draws no current, so the input current is zero, while the output (source) current is non-zero. The current gain $\frac{i_{out}}{i_{in}}$ is therefore infinite.