Question

When the MOSFET is in the ON state, the channel of the device behaves like:

• A. Constant resistance
• B. Inductance
• C. Capacitance
• D. Resistance and Inductance

Hint:

When fully ON, a MOSFET behaves like a constant low-resistance path (\( R_{DS(on)} \)), making it ideal for switching applications.

Answer 1

The Correct Option is A

Step 1: A MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) operates in three regions: - Cutoff Region: Acts like an open switch. - Linear (Ohmic) Region: Acts like a variable resistor. - Saturation Region: Functions as a current source. 
Step 2: When the MOSFET is fully ON, it operates in the linear region, where the channel behaves like a low-resistance path. 
Step 3: The ON-state resistance is called Drain-to-Source ON Resistance (\( R_{DS(on)} \)), which is constant and depends on: - Channel doping concentration. - Gate drive voltage. 
Step 4: Evaluating options: 
- (A) Constant resistance (Correct): The MOSFET channel behaves as a resistor in the ON state. 
- (B) Inductance (Incorrect): The channel does not exhibit significant inductive effects. 
- (C) Capacitance (Incorrect): Capacitances are present but do not dominate in the ON-state. 
- (D) Resistance and Inductance (Incorrect): The MOSFET channel primarily acts as a resistor when ON.