1. What is the MOSFET Current Equation?

The MOSFET current equation calculates the drain current (I_d) in saturation region based on the transconductance parameter (k), gate-source voltage (V_gs), and threshold voltage (V_th). This is a fundamental equation in MOSFET operation and circuit design.

2. How Does the Calculator Work?

The calculator uses the MOSFET current equation:

Where:

• \( I_d \) — Drain current (A)
• \( k \) — Transconductance parameter (A/V²)
• \( V_{gs} \) — Gate-source voltage (V)
• \( V_{th} \) — Threshold voltage (V)

Explanation: This equation describes the quadratic relationship between the gate-source overdrive voltage (V_gs - V_th) and the drain current in the saturation region.

3. Importance of Drain Current Calculation

Details: Accurate drain current calculation is crucial for designing MOSFET circuits, determining power consumption, and ensuring proper transistor operation in saturation region.

4. Using the Calculator

Tips: Enter k in A/V², voltages in volts. All values must be valid (k > 0). The equation is valid only when V_gs > V_th (transistor in saturation).

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range for k?
A: k values typically range from 10^-6 to 10^-3 A/V² for small-signal MOSFETs, but can be higher for power MOSFETs.

Q2: What if V_gs is less than V_th?
A: The transistor is in cutoff region and I_d ≈ 0 (the equation doesn't apply).

Q3: Does this equation work for all MOSFET regions?
A: No, this is specifically for saturation region. Different equations apply for linear/triode region.

Q4: How does temperature affect the calculation?
A: V_th decreases with temperature, which would increase I_d at fixed V_gs.

Q5: What about channel length modulation?
A: This simple model ignores channel length modulation. For more precision, multiply by (1 + λV_ds).