Overall Feedback Voltage Gain of Common-Source Amplifier Calculator

Formula Used:

\[ G_{fv} = -g_{mp} \times \left( \frac{R_{in}}{R_{in} + R_{sig}} \right) \times \left( \frac{1}{R_d} + \frac{1}{R_L} + \frac{1}{R_{out}} \right)^{-1} \]

MOSFET Primary Transconductance (g_mp):

Input Resistance (R_in):

Signal Resistance (R_sig):

Drain Resistance (R_d):

Load Resistance (R_L):

Finite Output Resistance (R_out):

Overall Feedback Voltage Gain (G_fv):

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1. What is the Overall Feedback Voltage Gain of Common-Source Amplifier?

The Overall Feedback Voltage Gain of a Common-Source Amplifier is a measure of the amplifier's gain that accounts for feedback effects. It represents the ratio of the output voltage to the input voltage when feedback is applied, providing a more accurate assessment of the amplifier's performance in practical circuits.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ G_{fv} = -g_{mp} \times \left( \frac{R_{in}}{R_{in} + R_{sig}} \right) \times \left( \frac{1}{R_d} + \frac{1}{R_L} + \frac{1}{R_{out}} \right)^{-1} \]

Where:

\( g_{mp} \) — MOSFET Primary Transconductance (S)
\( R_{in} \) — Input Resistance (Ω)
\( R_{sig} \) — Signal Resistance (Ω)
\( R_d \) — Drain Resistance (Ω)
\( R_L \) — Load Resistance (Ω)
\( R_{out} \) — Finite Output Resistance (Ω)

Explanation: The formula calculates the overall voltage gain by considering the transconductance of the MOSFET, the voltage division at the input, and the parallel combination of resistances at the output.

3. Importance of Feedback Voltage Gain Calculation

Details: Accurate calculation of feedback voltage gain is crucial for designing amplifier circuits, predicting circuit behavior, and ensuring proper signal amplification in electronic systems.

4. Using the Calculator

Tips: Enter all resistance values in ohms (Ω) and transconductance in siemens (S). All values must be positive and non-zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: Why is the gain negative in the formula?
A: The negative sign indicates that the common-source amplifier provides a 180-degree phase shift between input and output signals.

Q2: What is typical range for MOSFET transconductance?
A: MOSFET transconductance typically ranges from 0.001 to 0.1 S, depending on the device characteristics and operating conditions.

Q3: How does feedback affect amplifier performance?
A: Feedback can improve stability, reduce distortion, and make the gain less sensitive to component variations, but it typically reduces the overall gain.

Q4: What are common applications of common-source amplifiers?
A: Common-source amplifiers are widely used in RF circuits, audio amplifiers, and as building blocks in more complex integrated circuits.

Q5: How accurate is this calculation for practical circuits?
A: While this calculation provides a good approximation, actual circuit performance may vary due to parasitic elements, temperature effects, and device non-idealities.