Questions tagged [negative-feedback]
The negative-feedback tag has no usage guidance.
31 questions with no upvoted or accepted answers
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RC filters in JFET negative feedback
I saw a useful answer about JEFT negative feedback here and so I thought I'd ask for some help too!!
I'm attempting to create a JFET gain stage that uses a filter in a negative feedback loop to boost ...
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Voltage-divider bias common emitter calculations are yielding unexpected results
I performed an analysis on this voltage-divider-feedback common emitter. My result in simulation is relatively close, but doesn't quite check out. Where did I go wrong? I'm new to this and ...
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How do I perform ac analysis of common emitter with voltage divider feedback?
I'm working towards understanding voltage-shunt feedback. I'm about halfway there, and stuck. I am building a simple common emitter with voltage divider feedback.
I managed to get it biased to put ...
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Calculate feedback factor
Values and models are arbitrary. The circuit above was written on board (without values) as an exercise for "breaking the loop" method, however I do not agree with the answer which says the ...
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Op-amp 'overcompensation'
First, a bit of background; I'm trying to regulate a HV DC-DC converter using an op-amp with an NPN Darlington current booster. The DC-DC converter is a push-pull circuit driven at about 40 kHz that ...
user194170
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BJT - DC Negative Feedback Biasing
After getting some useful feedback from this question (BJT Common Emitter - Active Load Biasing) I've been trying to intuit how the output voltage presents itself. Through a bit of trial and error I'...
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Series current Feedback
I was tryig to build this circuit ("Series-feedback pair") from "Art of electronics" book (p. 150).
Since I do not have the exact components I tried to model it in LTSpice with ...
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Change in Base-Emitter Voltage due to Emitter Degeneration
I am stuck on this circuit from The Art of Electronics, page 117 figure 2.85A.
I have been working on how to derive the equation for the change in Vbe.
My calculations have been assuming that:
$$ \ ...
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Simple Stability and Feedback
I have a question, my book says that for the system in this picture:
If the system has G(s)*H(s) with a module of 1 (0dB) and a phase of -180°, the system is in Simple Stability, so it is like in ...
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What will be small signal trans resistance gain of shown circuit?
Take beta = 99.
I analysed this circuit using first considering this circuit as feedback circuit with shunt-shunt type of feedback and then did the same analysis considering that the circuit is a ...
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How is this series series feedback topology forOPAMP?
This is stated as series series type of negative feedback but why.
Whereas this one is series shunt topology
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Potential ground loop issue in DC-DC common ground circuit
I am trying to setup a dedicated battery for my dash-camera, this will provide continuous power when the ignition is OFF and has a manual NC switch to turn off the circuit when not needed.
I ...
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Why input signal of negative feedback amplifier is Vs - Vf?
The block diagram below is from my textbook. I don't understand why the input voltage Vi = Vs - Vf. Take an example as the image with numbers on it, I know its not correct in reality but just assume ...
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What are the necessary conditions to prevent latch-up problem for Oscillators?
In his chapter on oscillator design, Razavi discusses the issue of latch-up and proposes several methods to eliminate it. However, he doesn't provide explanations for these methods. Could anyone ...
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How to determine if the feedback is positive or negative?
How to know if I have to apply the formula Af=A/(1-AB) [positive feedback] or Af=A/(1+AB) [negative feedback]?
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voltage follower design question
Hi , I am trying to build a simple voltage follower circuit in IC. I have tried to build ideal Op-Amp as a transconductor. Now, it requires minimum bias voltage for it to operate as a transcondcutor (...
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Problem with Arduino MEGA and opamp LM741CN for feedback ammeter
I am trying to create a feedback ammeter using Arduino MEGA ADC and OpAmp LM741CN. In order to perform a proof of concept, I use Arduino MEGA, LED, and Resistor 1 MΩ, then I read its current with a ...
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Discussion on demonstrating saturation in operational amplifiers with positive feedback, and simulation problems
I have been dedicating my time to the study of Operational Amplifiers for the past few weeks.
I understood that an amplifier in an open loop configuration has a very high gain, in the case \$A \to \...
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What is the purpose of a negative feedback resistor in a schmitt trigger?
This schmitt trigger is used with an integrator to create a triangle/square wave oscillator but R5 has been added to the typical inverting schmitt trigger topology. I know that in simulation, this ...
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Output resistance in negative feedback
I was studying negative feedback in voltage amplifiers. I found this on Wikipedia for calculating input resistance as shown below.
Following the similar method, I tried to calculate the output ...
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Negative feedback gain sensitivity
What happens to the gain sensitivity of negative feedback system due to fractional change in open loop gain when feedback gain His about 0.01-0.05.
Here's my work:
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BJT or MOS negative feedback analysis
I am looking for a resource that includes analysis of feedback circuits. I have found something on sedra smith microelectronic circuits but not enough for me. Could you suggest me some resource ? It ...
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Voltage-voltage Feedback and common-collector analysis?
(This question is related to this one here, where I attempted to understand how the discrete component values in a negative feedback amplifier are represented by the closed-loop gain and feedback ...
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Op-Amp Summing Amplifier Not Working
I have this below circuit op-amp summing amplifier with its below result:
But in my actual circuit all components are the same except the op-amp.
I am using this op-amp part in my practical circuit :
...
user220456
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What unit is expressing the effect of this capacitor in a common emitter amplifier?
I'm working through this handout I3.PDF in my attempt to understand negative feedback in amplifiers. The following formula appears, in which the author is substituting \$v_{out}\$ and \$v_{in}\$ to ...
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Effect of a heavy load on op amp output
Simulated on Multisim 14.0
In the above circuit, without RL the circuit behaves quite normally with a non inverting gain of 50 for any input at V1 till the output saturates to 15V.
Things however ...
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What will be vo/i for given circuit?
Solve using both approaches first using small signal analysis and then using feedback analysis.
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How to solve practical OPAMP with finite differential resistance and finite offset current while other parameters can be considered ideal?
simulate this circuit – Schematic created using CircuitLab
Ip(bias)=200nA
rd=differential resistance=5Mohm
a=infinite
What should be its output?
I am confused if I should consider negative ...
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532
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How do I calculate a PID controller gain for a certain damping coefficient?
I have a third order process and I have to design a PID controller by cancelling out the two most dominant poles of the process. The process transfer function is:
The controller is of the form, where ...
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Pole-placement problem
I was following this example of implementing a pole-placement with an Integral controller.
Matrices A_star=[-5 -3 0;1 0 0;0 -1 0]
B_star=[1;0;0]
desired poles -100,-8+i*11,-8-i*11
I know the ...
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Question about the slew rate
Let's consider an op-amp:
From basic courses of electronics, we know that the output voltage as a function of the differential input is given by the following picture:
Now, assuming that:
the op-...
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