Common-Mode Current Gain Of Controlled Source Transistor Calculator

Common-Mode Current Gain Formula:

\[ A_{cmi} = -\frac{1}{2 \times g_m \times R_o} \]

Common-Mode Current Gain (A_cmi):

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1. What is Common-Mode Current Gain?

Common-mode current gain refers to the amplification given to signals that appear on both inputs relative to the common (typically ground). It is a crucial parameter in differential amplifier circuits and controlled source transistor configurations.

2. How Does the Calculator Work?

The calculator uses the Common-Mode Current Gain formula:

\[ A_{cmi} = -\frac{1}{2 \times g_m \times R_o} \]

Where:

\( A_{cmi} \) — Common-Mode Current Gain
\( g_m \) — Transconductance (Siemens)
\( R_o \) — Output Resistance (Ohm)

Explanation: This formula calculates the common-mode current gain for controlled source transistor configurations, where the negative sign indicates phase inversion.

3. Importance of Common-Mode Current Gain

Details: Understanding common-mode current gain is essential for analyzing differential amplifier performance, noise rejection capabilities, and overall circuit stability in electronic systems.

4. Using the Calculator

Tips: Enter transconductance in Siemens and output resistance in Ohms. Both values must be positive and non-zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is transconductance (g_m)?
A: Transconductance is the change in the drain current divided by the small change in the gate/source voltage with a constant drain/source voltage.

Q2: What does output resistance (R_o) represent?
A: Output resistance is the measure of the opposition to current flow, both static and dynamic, into the load network being connected that is internal to the electrical source.

Q3: Why is the common-mode current gain negative?
A: The negative sign indicates that the output signal is 180 degrees out of phase with the common-mode input signal.

Q4: What are typical values for transconductance?
A: Transconductance values typically range from microsiemens to millisiemens depending on the transistor type and operating conditions.

Q5: How does output resistance affect common-mode gain?
A: Higher output resistance generally results in lower common-mode current gain, as the gain is inversely proportional to the output resistance.