Question

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

• A. 0
• B. 1
• C. 100
• D. infinite

Hint:

In an ideal MOSFET common drain amplifier, the small signal current gain is always 1, as it is a voltage follower with no amplification of current.

Answer 1

The Correct Option is B

Step 1: Understand the common drain amplifier.
A common drain amplifier is similar to a voltage follower or buffer amplifier. For an ideal MOSFET in saturation, the small signal current gain is typically unity (1). This is because the current flowing through the drain is the same as the current flowing through the source, resulting in a current gain of 1. Step 2: Analyzing the options.
- (A) 0: This is incorrect because the current gain is not zero for an ideal MOSFET in saturation.
- (B) 1: This is correct. In a common drain amplifier with an ideal MOSFET, the current gain is 1.
- (C) 100: This is incorrect because the current gain is not that large for an ideal MOSFET in saturation.
- (D) Infinite: This is incorrect because the ideal current gain for a common drain amplifier is unity, not infinite.
Step 3: Conclusion.
The correct answer is (B) 1, as the small signal current gain for an ideal common drain amplifier is unity.