Common Mode Rejection Ratio of BJT Differential Amplifier in dB Calculator

✖Differential Gain is defined as when a differential input is supplied i.e. input 1 is not equal to input 2.ⓘ Differential Gain [A_d]			+10% -10%
✖Common Mode Gain refers to the amplification given to signals that appear on both inputs relative to the common (typically ground).ⓘ Common Mode Gain [A_cm]			+10% -10%

✖Common Mode Rejection Ratio is the ratio of the common-mode gain to differential-mode gain.ⓘ Common Mode Rejection Ratio of BJT Differential Amplifier in dB [CMRR]

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Formula

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Common Mode Rejection Ratio of BJT Differential Amplifier in dB

Formula

`"CMRR" = 20*log10("modulus"("A"_{"d"}/"A"_{"cm"}))`

Example

`"-18.381975dB"=20*log10("modulus"("0.253dB"/"2.1"))`

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Common Mode Rejection Ratio of BJT Differential Amplifier in dB Solution

STEP 0: Pre-Calculation Summary

Formula Used

Common Mode Rejection Ratio = 20*log10(modulus(Differential Gain/Common Mode Gain))
CMRR = 20*log10(modulus(A_d/A_cm))
This formula uses 2 Functions, 3 Variables

Functions Used

log10 - The common logarithm, also known as the base-10 logarithm or the decimal logarithm, is a mathematical function that is the inverse of the exponential function., log10(Number)
modulus - Modulus of a number is the remainder when that number is divided by another number., modulus

Variables Used

Common Mode Rejection Ratio - (Measured in Decibel) - Common Mode Rejection Ratio is the ratio of the common-mode gain to differential-mode gain.
Differential Gain - (Measured in Decibel) - Differential Gain is defined as when a differential input is supplied i.e. input 1 is not equal to input 2.
Common Mode Gain - Common Mode Gain refers to the amplification given to signals that appear on both inputs relative to the common (typically ground).

STEP 1: Convert Input(s) to Base Unit

Differential Gain: 0.253 Decibel --> 0.253 Decibel No Conversion Required
Common Mode Gain: 2.1 --> No Conversion Required

STEP 2: Evaluate Formula

Substituting Input Values in Formula

CMRR = 20*log10(modulus(A_d/A_cm)) --> 20*log10(modulus(0.253/2.1))

Evaluating ... ...

CMRR = -18.381975471162

STEP 3: Convert Result to Output's Unit

-18.381975471162 Decibel --> No Conversion Required

FINAL ANSWER

-18.381975471162 ≈ -18.381975 Decibel <-- Common Mode Rejection Ratio

(Calculation completed in 00.020 seconds)

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Created by Prahalad Singh

Jaipur Engineering College and Research Centre (JECRC), Jaipur

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Birsa Institute of Technology (BIT), Sindri

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< 4 DC Offset Calculators

Common Mode Rejection Ratio of BJT Differential Amplifier in dB

Go Common Mode Rejection Ratio = 20*log10(modulus(Differential Gain/Common Mode Gain))

Input Offset Voltage of BJT Differential Amplifier

Go Input Offset Voltage = Threshold Voltage*(Change in Collector Resistance/Collector Resistance)

Input Offset Current of Differential Amplifier

Go Input Offset Current = modulus(Input Bias Current 1-Input Bias Current 2)

Common Mode Gain of BJT Differential Amplifier

Go Common Mode Gain = Differential Output Voltage/Differential Input Voltage

Common Mode Rejection Ratio of BJT Differential Amplifier in dB Formula

Common Mode Rejection Ratio = 20*log10(modulus(Differential Gain/Common Mode Gain))
CMRR = 20*log10(modulus(A_d/A_cm))

What are typical values for input offset current & input bias current?

Typical values for general-purpose op amps that use bipolar transistors are I_B 100 nA and
I_os = 10 nA.

How to Calculate Common Mode Rejection Ratio of BJT Differential Amplifier in dB?

Common Mode Rejection Ratio of BJT Differential Amplifier in dB calculator uses Common Mode Rejection Ratio = 20*log10(modulus(Differential Gain/Common Mode Gain)) to calculate the Common Mode Rejection Ratio, Common Mode Rejection Ratio of BJT Differential Amplifier in dB is defined as the ratio of the common-mode gain to differential-mode gain. Common Mode Rejection Ratio is denoted by CMRR symbol.

How to calculate Common Mode Rejection Ratio of BJT Differential Amplifier in dB using this online calculator? To use this online calculator for Common Mode Rejection Ratio of BJT Differential Amplifier in dB, enter Differential Gain (A_d) & Common Mode Gain (A_cm) and hit the calculate button. Here is how the Common Mode Rejection Ratio of BJT Differential Amplifier in dB calculation can be explained with given input values -> -18.381975 = 20*log10(modulus(0.253/2.1)).

FAQ

What is Common Mode Rejection Ratio of BJT Differential Amplifier in dB?

Common Mode Rejection Ratio of BJT Differential Amplifier in dB is defined as the ratio of the common-mode gain to differential-mode gain and is represented as CMRR = 20*log10(modulus(A_d/A_cm)) or Common Mode Rejection Ratio = 20*log10(modulus(Differential Gain/Common Mode Gain)). Differential Gain is defined as when a differential input is supplied i.e. input 1 is not equal to input 2 & Common Mode Gain refers to the amplification given to signals that appear on both inputs relative to the common (typically ground).

How to calculate Common Mode Rejection Ratio of BJT Differential Amplifier in dB?

Common Mode Rejection Ratio of BJT Differential Amplifier in dB is defined as the ratio of the common-mode gain to differential-mode gain is calculated using Common Mode Rejection Ratio = 20*log10(modulus(Differential Gain/Common Mode Gain)). To calculate Common Mode Rejection Ratio of BJT Differential Amplifier in dB, you need Differential Gain (A_d) & Common Mode Gain (A_cm). With our tool, you need to enter the respective value for Differential Gain & Common Mode Gain and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.

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