Common Mode Gain Equation:
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Common Mode Gain (Acm) is typically much smaller than the differential gain. Acm is the gain given to a voltage that appears on both input terminals with respect to the ground in controlled source transistor circuits.
The calculator uses the Common Mode Gain equation:
Where:
Explanation: The equation calculates the common mode gain in decibels by taking the ratio of small signal to differential input signal and applying a logarithmic scale with a multiplier of 20.
Details: Accurate common mode gain calculation is crucial for analyzing the performance of differential amplifiers, determining common mode rejection ratio (CMRR), and ensuring proper signal processing in electronic circuits.
Tips: Enter small signal voltage and differential input signal voltage in volts. Both values must be positive and greater than zero for accurate calculation.
Q1: What is the significance of the 20 multiplier in the formula?
A: The multiplier of 20 is used to convert the voltage ratio to decibels, which is the standard unit for gain measurements in electronic systems.
Q2: What are typical values for common mode gain?
A: Common mode gain values are typically much smaller than differential gains, often ranging from a few decibels to negative values, indicating signal attenuation.
Q3: How does common mode gain affect circuit performance?
A: Lower common mode gain values indicate better common mode rejection, which is desirable in differential amplifiers to suppress noise and interference that appears equally on both inputs.
Q4: What is the relationship between common mode gain and CMRR?
A: Common Mode Rejection Ratio (CMRR) is calculated as the ratio of differential gain to common mode gain. A higher CMRR indicates better rejection of common mode signals.
Q5: When should this calculation be used?
A: This calculation is essential when designing or analyzing differential amplifiers, operational amplifiers, and other circuits where common mode signal rejection is important for proper operation.