Drain Source Voltage of FET Calculator

FET Drain Source Voltage Equation:

\[ V_{ds(fet)} = V_{dd(fet)} - I_{d(fet)} \times (R_{d(fet)} + R_{s(fet)}) \]

Supply Voltage at Drain FET:

Drain Current FET:

Drain Resistance FET:

Source Resistance FET:

Drain Source Voltage FET:

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Drain Source Voltage of FET?

Drain Source Voltage (Vds) of a Field Effect Transistor (FET) is the voltage difference between the drain and source terminals. It determines the operating region of the FET (cutoff, triode, or saturation) and influences the drain current flow through the device.

2. How Does the Calculator Work?

The calculator uses the FET Drain Source Voltage equation:

\[ V_{ds(fet)} = V_{dd(fet)} - I_{d(fet)} \times (R_{d(fet)} + R_{s(fet)}) \]

Where:

\( V_{ds(fet)} \) — Drain Source Voltage FET (V)
\( V_{dd(fet)} \) — Supply Voltage at Drain FET (V)
\( I_{d(fet)} \) — Drain Current FET (A)
\( R_{d(fet)} \) — Drain Resistance FET (Ω)
\( R_{s(fet)} \) — Source Resistance FET (Ω)

Explanation: This equation calculates the voltage drop across the drain-source terminals by subtracting the voltage drops across the drain and source resistances from the supply voltage.

3. Importance of Drain Source Voltage Calculation

Details: Accurate Vds calculation is crucial for FET circuit design, ensuring proper biasing, determining operating regions, preventing device breakdown, and optimizing circuit performance in amplifier and switching applications.

4. Using the Calculator

Tips: Enter supply voltage in volts, drain current in amperes, and resistances in ohms. All values must be non-negative. The calculator will compute the drain-source voltage based on the provided parameters.

5. Frequently Asked Questions (FAQ)

Q1: What is the significance of drain-source voltage in FET operation?
A: Vds determines the FET's operating region - cutoff when Vds is low, triode/linear region for moderate Vds, and saturation region for higher Vds values where the FET acts as a constant current source.

Q2: How does drain-source voltage affect drain current?
A: In the saturation region, drain current is relatively independent of Vds and primarily controlled by gate-source voltage. In the triode region, drain current increases linearly with Vds.

Q3: What happens if Vds exceeds the maximum rating?
A: Exceeding the maximum Vds rating can cause device breakdown, permanent damage to the FET, and catastrophic failure of the circuit.

Q4: How do drain and source resistances affect Vds?
A: Higher drain and source resistances cause greater voltage drops, reducing the actual Vds across the FET for a given supply voltage and drain current.

Q5: Can this calculator be used for both JFET and MOSFET devices?
A: Yes, this voltage calculation applies to both JFETs and MOSFETs when considering the external circuit resistances and supply voltage.