FormulaDen.com

Physics Chemistry Math Chemical Engineering Civil Electrical Electronics Electronics and Instrumentation Materials Science Mechanical Production Engineering Financial Health

Common Mode Gain of BJT Formula

Fx Copy

LaTeX Copy

Common Mode Gain 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. Check FAQs

A cm = - (\frac{R c}{2 \cdot R o}) \cdot (\frac{ΔR c}{R c})

A_cm - Common Mode Gain?R_c - Collector Resistance?R_o - Output Resistance?ΔR_c - Change in Collector Resistance?

Common Mode Gain of BJT Example

With values

With units

Only example

Here is how the Common Mode Gain of BJT equation looks like with Values.

Here is how the Common Mode Gain of BJT equation looks like with Units.

Here is how the Common Mode Gain of BJT equation looks like.

-0.566 = - (\frac{3.75}{2 \cdot 2.12}) \cdot (\frac{2.4}{3.75})

-0.566dB = - (\frac{3.75kΩ}{2 \cdot 2.12kΩ}) \cdot (\frac{2.4kΩ}{3.75kΩ})

-0.566 = - (\frac{3.75}{2 \cdot 2.12}) \cdot (\frac{2.4}{3.75})

Tip: Use pencil ( Pencil

) icon above to edit Input Values and Units.

Calculate

Recalculate

Solution

Copy

Reset

You are here -

Home » Category

Engineering » Category

Electronics » Category

Analog Electronics » fx Common Mode Gain of BJT

Common Mode Gain of BJT Solution

Follow our step by step solution on how to calculate Common Mode Gain of BJT?

FIRST Step Consider the formula

A cm = - (\frac{R c}{2 \cdot R o}) \cdot (\frac{ΔR c}{R c})

Next Step Substitute values of Variables

∴

A cm = - (\frac{3.75kΩ}{2 \cdot 2.12kΩ}) \cdot (\frac{2.4kΩ}{3.75kΩ})

Next Step Convert Units

∴

A cm = - (\frac{3750Ω}{2 \cdot 2120Ω}) \cdot (\frac{2400Ω}{3750Ω})

Next Step Prepare to Evaluate

∴

A cm = - (\frac{3750}{2 \cdot 2120}) \cdot (\frac{2400}{3750})

Next Step Evaluate

∴

A cm = -0.566037735849057dB

LAST Step Rounding Answer

∴

A cm = -0.566dB

Common Mode Gain of BJT Formula Elements

Variables

Common Mode Gain

Common Mode Gain 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.

Symbol: A_cm

Measurement: NoiseUnit: dB

Note: Value can be positive or negative.

Formulas to find Common Mode Gain

Collector Resistance

Collector Resistance (Rc)helps to set the transistor at the "operating point" of the amplifier. The purpose of the emitter resistor Re is to prevent "thermal runaway".

Symbol: R_c

Measurement: Electric ResistanceUnit: kΩ

Note: Value can be positive or negative.

Formulas to find Collector Resistance

Output Resistance

Output resistance is the value of resistance of the network.

Symbol: R_o

Measurement: Electric ResistanceUnit: kΩ

Note: Value can be positive or negative.

Formulas to find Output Resistance

Change in Collector Resistance

Change in collector resistance is the increment or decrement in resistance passing through the collector region.

Symbol: ΔR_c

Measurement: Electric ResistanceUnit: kΩ

Note: Value can be positive or negative.

Formulas to find Change in Collector Resistance

Other formulas in Amplification Factor or Gain category

Go Short-Circuit Current Gain

A i = \frac{I o}{I in}

Go Open Circuit Voltage Gain given Open Circuit Transresistance

A = \frac{R m}{R in}

Go Voltage Gain given Collector Current

A v = - (\frac{I c}{V t}) \cdot R c

Go Voltage Gain given all Voltages

A v = - \frac{V DD - V CE}{V t}

How to Evaluate Common Mode Gain of BJT?

Common Mode Gain of BJT evaluator uses Common Mode Gain = -(Collector Resistance/(2*Output Resistance))*(Change in Collector Resistance/Collector Resistance) to evaluate the Common Mode Gain, The Common mode gain of BJT formula is defined as the common mode gain of a BJT amplifier is a measure of how much the output voltage changes when there is a change in the common-mode input voltage. It is typically expressed as a ratio or a percentage. Common Mode Gain is denoted by A_cm symbol.

How to evaluate Common Mode Gain of BJT using this online evaluator? To use this online evaluator for Common Mode Gain of BJT, enter Collector Resistance (R_c), Output Resistance (R_o) & Change in Collector Resistance (ΔR_c) and hit the calculate button.

FAQs on Common Mode Gain of BJT

What is the formula to find Common Mode Gain of BJT?

The formula of Common Mode Gain of BJT is expressed as Common Mode Gain = -(Collector Resistance/(2*Output Resistance))*(Change in Collector Resistance/Collector Resistance). Here is an example- -0.566038 = -(3750/(2*2120))*(2400/3750).

How to calculate Common Mode Gain of BJT?

With Collector Resistance (R_c), Output Resistance (R_o) & Change in Collector Resistance (ΔR_c) we can find Common Mode Gain of BJT using the formula - Common Mode Gain = -(Collector Resistance/(2*Output Resistance))*(Change in Collector Resistance/Collector Resistance).

Can the Common Mode Gain of BJT be negative?

Yes, the Common Mode Gain of BJT, measured in Noise can be negative.

Which unit is used to measure Common Mode Gain of BJT?

Common Mode Gain of BJT is usually measured using the Decibel[dB] for Noise. Neper[dB], MilliDecibel[dB] are the few other units in which Common Mode Gain of BJT can be measured.

Let Others Know

✖

Facebook

Twitter

Copied!

: Value
: Unit

Common Mode Gain of BJT Formula

Common Mode Gain of BJT Example

Common Mode Gain of BJT Solution

Common Mode Gain of BJT Formula Elements

Other formulas in Amplification Factor or Gain category

How to Evaluate Common Mode Gain of BJT?

FAQs on Common Mode Gain of BJT

Variable Name