Question

A MOSFET operates in the saturation region when the gate-to-source voltage exceeds what?

• A. Drain voltage
• B. Threshold voltage
• C. Source voltage
• D. Gate voltage

Hint:

MOSFET ON condition → $V_{GS}>V_{th}$ → Required for saturation region.

Answer 1

The Correct Option is B

Concept: MOSFET operation regions depend on the relationship between gate-to-source voltage ($V_{GS}$), threshold voltage ($V_{th}$), and drain-to-source voltage ($V_{DS}$).
Step 1: Condition for conduction.
A MOSFET starts conducting when: \[ V_{GS}>V_{th} \]
Step 2: Condition for saturation region.
For saturation: \[ V_{GS}>V_{th} \quad \text{and} \quad V_{DS} \geq (V_{GS} - V_{th}) \]
Step 3: Interpretation.
The key requirement is that the gate-to-source voltage must exceed the threshold voltage to form a conducting channel.
Step 4: Conclusion.
Thus, the MOSFET enters operation (and saturation condition builds upon it) when $V_{GS}$ exceeds the threshold voltage.