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Questions tagged [feedback]

Feedback is a process whereby information from an output of a signal is used (intentionally or unintentionally) to alter the input of the same signal. Commonly used in operational amplifiers. An everyday example is the high-pitched audio frequency heard when a microphone picks up audio from its own amplified output.

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60 views

Why has this configuration chosen for feedback? [duplicate]

I'm a newbie in electronics and Trying to understand and build this circuit. would somebody tell me the rule of R1 & C2 in this circuit and their magnitude effect on the controlling of process.why ...
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Implementing non-linear time delay

I have a feedback system including an OP-amp in comparator mode and a transistor, in present time it acts like a regulator, constantly limiting the current through the transistor to a certain value. ...
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769 views

Transistor based Voltage-Current Converter

For my last design question, Transistor current control with collector feedback, I want to add a NPN transistor between OpAmp and already shown transistor in common emitter mode. With new design, the ...
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285 views

Stability measurement of Operational Amplifier

All, I am trying to simulate as well as measure the stability of an op-amp with high gain (~50dB). The gain is necessary to boost a low level signal. I am struggling to understand if I am making ...
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3answers
120 views

Op amp feedback

I have confusion related to feedback in op amp. We know that the input resistance of op amp is very very high so why does the input current not flow from input to the feedback and directly to output. ...
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2answers
210 views

How can I avoid saturation in current source amplifier?

I'm designing a class d amplifier with current feedback as in figure below with the following features: Vbus=50V Iout programmable from 100mA to 1A rms Vout=35Vrms max When the load overcomes the ...
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129 views

How to get Voltage gain from a cascaded transformers?

I am solving a problem from Fundamentals of Electric Circuits Chapter 13, Problem 65. I know how to solve it using mesh analysis, on the other hand I am looking for a simpler method, so I am trying ...
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3answers
151 views

What is meant by 'modified forward path' in this op-amp problem?

What is a modified forward path? In the practise exam paper I'm doing I'm given this circuit and asked to draw an equivalent circuit of the 'modified forward path amplifier'. I'm told that it should ...
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1answer
370 views

transfer function op amp feedback circuit

Does anyone know how to calculate the transfer function for this circuit if Vref is the input an Vo the output? Thank you
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197 views

Help understanding onboard power supply measurement test connections

I recently came across this circuit for measuring the output of a TPS54620 switching regulator (12V->3.3V). I'm not a power engineer, so I'd like some help understanding the parts in red boxes (...
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1answer
375 views

Calculating feedback factor \$V_f/I_o\$

I'm unsure how to calcuate the feedback factor here. It's a voltage / current, so it's a resistor value, but what do you do when the values aren't from the same source? ie. it's \$V_f\$ and \$I_o\$ ...
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1answer
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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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3answers
104 views

Changing output voltage of a buck converter by electronically swapping the feedback resistors

I am going to design a circuit which is going to output some digital signals. The output stage of the circuit will have some level shifters. The level shifters will give flexibility to the user to ...
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4answers
104 views

Isn't the amplification in amps always going towards infinity?

In my textbook I have a scheme like this: Which is trying to explain the principle of feedback. So the singal X1 is amplified into X2, part of X2 is returned and added with X1, which is again ...
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1answer
323 views

Differential Amplifier with Global Negative Feedback

This question refers to audio amplifier design, using BJTs only. I am wondering how differential stage amplifier plays an important role in hi-fi audio amplifiers. According to this book (where ...
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1answer
4k views

FM transmitter feedback capacitor [closed]

Why is a capacitor connected across the collector-emitter of the transistor? How does this capacitor prevent decay of LC oscillations?
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1answer
100 views

Does current flow from neutral to phase?

In AC supply we have both positive and negative cycles then in positive half cycle current flows from phase to neutral and then in negative half cycle current flows from neutral to phase - how can ...
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1answer
91 views

Replacing UPS of a CPU with whole home suppression (undervoltage) system [closed]

I need a new UPS however the knowledge acquired in the last years is preventing me from getting one I live in a large city (127v), and voltages rarely go above 130v, however it has happened at least ...
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1answer
101 views

What happens if we send consecutive CAN frames and wait for their acknowledge back?

I have a general question about CAN transmission and the acknowledgment. I want to send multiple CAN frames (burst frames), and after I receive them all in HOST, I want to read their ack from the Bus:...
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1answer
747 views

Stepper motors: feedback to detect successful step?

Is it possible to have a stepper motor driver circuit detect if the motor has successfully stepped, ie not stalled, or stepped too quickly? (Not microstepping).
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3answers
218 views

Can you switch between 2 tank circuits using a relay?

Say I have an oscillator that needs to span between 1 GHz and 1 Mhz. Ill be controlling it with a microcontroller, probably an arduino. According to this, http://faculty.mu.edu.sa/public/uploads/...
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1answer
376 views

Dead-reckoning vs feedback for motor position control of turntable

I am constructing a small turntable that holds a plastic cup and should be controlled to stop at one of eight positions. (Where it will receive a shot of liquid; think "Auto-cocktails"). I'm wondering ...
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3answers
149 views

Negative feedback - equilibrium

I have a basic question regarding negative feedback and stability. As I've understood it, negative feedback is supposed to promote equilibrium. But suppose we have negative feedback loop block ...
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1answer
102 views

Looking for a LED transmitter/receiver package(or group of components)

I am trying to design a system that utilizes 355nm and 370nm LEDs. I want to keep their intensity stabilized at a certain value, so I want to create a feedback loop. I am using these LEDs as ...
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2answers
682 views

Why is a 0V DC point at the output of an op amp critical for feedback?

I am designing an op amp that consists of an active loaded single ended output differential amplifier that is connected to a buffer stage and then an output stage. When the input signal is connected ...
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1answer
138 views

How do I use one feedback pin with two error amplifiers?

I know there is a similar question asked: TL494CN and error amplifier. However, that link does not answer my question. If I need one current loop and one voltage loop on the power supply, how should ...
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1answer
209 views

Common source amplifier, source degeneration and determining the cutoff frequency

I have a n-MOS transistor with the following biasing network: I have to determine the cutoff frequency due to GS and GD capacitances The method used by my book is to first redefine the ...
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1answer
180 views

How does CMFB works?

I'm working on simple OTA. I know the purpose of CMFB, I just don't know how exactly in this particular case it works: ppt http://s2.ifotos.pl/img/esepng_ahqpseq.png Common mode voltage increases (...
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2answers
284 views

Force feedback electromagnetic power requirments

I want to design a force feedback system for a gun controller which will use an electromagnetic drive system to replicate gun recoil. I've explored a range of designs but they all seem to require a ...
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1answer
401 views

Pull-up resistor causing unintentional voltage divider?

I'm trying to use the output of a comparator as the input of a schmitt trigger built with positive feedback on another comparator. Both have open collector outputs. When the two are not connected, ...
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2answers
116 views

Feedback Stability Comparison [closed]

Compare the Feedback conditions given below in terms of stability:- Negative Feedback Positive Feedback with LoopGain < 1 Positive Feedback with LoopGain = 1 Positive Feedback with LoopGain > 1 ...
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2answers
960 views

Eliminating battery/bluetooth feedback

Let me preface this with saying that I'm a complete amateur with electronics and know very little of theory behind it. I think my question is easily answered but I just can't find the right info. I ...
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3answers
7k views

The purpose of voltage-dividers in op-amp feedback?

simulate this circuit – Schematic created using CircuitLab So, here we have a typical op-amp with negative feedback. The non-inverting input is at virtual-ground, and if the input is higher or ...
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1answer
233 views

How does the feedback in this circuit work? [duplicate]

I several hours of researching and examining, there are still questions I have about the feedback of this SMPS. The LT4430 has a FB regulated voltage of 0.60 V. The way I understand this is.. if the ...
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1answer
74 views

Feedback Criterion for Oscillations [closed]

In the Feedback equation A/(1+AB) the criterion to be fulfilled is |AB|=1 and phase shift = 180 deg. In this case the poles of 1+AB would be on img axis at \$w_0\$. But in practical cases |AB| is made ...
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1answer
116 views

What improved frequency response means? [duplicate]

I was looking at the question "what feedback exactly means"(applied in Op-amps). In the negative feedback even though there is a decrease in the op-amps overall gain, it's widely used because it ...
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1answer
158 views

op amp two feedback [closed]

Hi this circuit have two feedback.input signal is an exponential.amplitude is about .7v and 1/4 4066 switch connect a segment from op amp output.pin 6 connect to a puls and connect a segment from ...
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2answers
79 views

Are those two filters equal?

Are those two filters equal to each other in their functionality? Of not, what is the difference between them mathematically speaking (zeros, poles, etc)? Also, what is the difference in their ...
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6answers
5k views

What is feedback in electronics? [duplicate]

I dont want to know that we have two types of feedbacks and why it was invented,I just want an explanation in simple words of what feedback is.