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Questions tagged [differential-amplifier]

For questions about circuits that amplify the difference between two input signals but not the signal common to the two inputs (e.g. the long-tailed pair). Do not use for questions about operational amplifiers (which are a type of difference amplifier) unless the op amp is used as a differential amplifier -- use only the "operational-amplifier" tag for most questions about op amps (e.g. an op amp as an inverting amplifier).

For questions about circuits that amplify the difference between two input signals but not the signal common to the two inputs (e.g. the long-tailed pair or op amp differential amplifier). Do not use for questions about operational amplifiers (which are a type of differential amplifier) unless the op amp is used as a differential amplifier -- use only for most questions about op amps (e.g. an op amp as an inverting amplifier).

297 questions
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My question is about differential amplifier. I don`t know \$2\frac{\Delta R}{R}\$ proof

My question is about differential amplifier. I don`t know \$2\frac{\Delta R}{R}\$ proof. I don't know this proof. Why \$Av(cm) = 2 \frac{\Delta R}{R}\$? This is my solution.
SDG
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Why is Q1 taken as 'on' and Q2 as 'off' in the differential amplifier?

The book tells that we can arrive at the conclusion by reasoning. Why can the voltage at the emitter not be -0.7 V so that both the transistors would be on?
Deviprasad V R
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Single supply differential amplifier

I am wondering is it possible to design a differential (or instrumentation) amplifier that will operate from single supply? I have a 2Vp-p and 0.2Vp-p sine wave signals that need to go thru the differential amplifier. They both swing positive and…
Golaž
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Are Differential Line Drivers same as FDA or similair as Balun ? How we use them differently?

I'm trying to understand the difference between differential line drivers, FDA and baluns. I know that FDA and Blaun both can be used to driver ADCs and baluns are usually AC coupled and adding less noise. But I don't know much about differential…
X.LI
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How can I go about understanding an electronic circuit?

I have this circuit: My goal is to gain a qualitative understanding of what VO1 and VO2 are going to look like for different signals V3 and V4 applied. Because you can not calculate with BJTs or electronic components in general, I would like to ask…
n328
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Differential amplifier exercise problem

I am preparing for an exam and I am not sure if my solution is correct for this problem: We have a differential amplifier with 2 NPN transistors (T1, T2). T1's collector is directly connected to the power supply \$V_{CC}=15V\$, while T2's…
SantaXL
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Should gain of this differential circuit be absolute value?

Content is from the book Design of Analog CMOS Integrated Circuits (https://electrovolt.ir/wp-content/uploads/2014/08/Design-of-Analog-CMOS-Integrated-Circuit-2nd-Edition-ElectroVolt.ir_.pdf) on Page 112. Due to a manufacturing error, in the circuit…
kile
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Differential Amplifier Output - Analog Devices Calculator

Dear All, Below it shown the output of an automated calculator provided by Analog Devices for calculating the inputs and outputs of a differential amplifier Calc_Link. For the output shown VoutP = {2...3...2...1...2}, VoutN = {2...1...2...3...2}…
MrT
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Differential amplifier current source problem

I got this question on my exam: Assume the two input voltages \$v^+\$ and \$v^-\$ are equal such that \$v^+=v^-=v\$, and the two transistors Q1 and Q2 are identical. What is the lowest value for \$v\$ before the current source breaks down? Eg. if…
Simhau
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Differential multi-feedback band-pass filter design

I am trying to design a multi-feedback differential band-pass filter. While doing calculations I just took Texas Instr. design guides, but nowhere is mentioned exactly how to realize the filter for the required specifications. Example: I need a pass…
Narendra Allu
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Diff amp ac equivalent circuit confusion

In the circuit below, base of Q2 is grounded. Even though base of Q2 is grounded in the circuit, the ac equivalent circuit(T model) seems to suggest that one end of the current source Q2 is also grounded(Dotted region)! Does this mean \$r_e+R_E\$…
across
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Common mode Rejection ratio

Why is CMRR infinite for coupled differential amplifiers when Re increases ?? I cant seem to understand what happens on making Re infinite.
Jeffy
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Configuration differential amplifier in different power condition

On the left-hand side is a typical differential amplifier with Vcc and -Vcc. On the right-hand side I kept Vcc but changed -Vcc to GND. Hence there are many things wrong with that configuration if I keep the other components unchanged. What should…
South goodman
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