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 ...

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37 views

How could I check how well two objects are aligned? [closed]

I am trying to design a tool that requires the user to align two cylindrical objects within a fraction of an inch (the user cannot see the cylinders, as they will be within a sleeve covering the ...
0
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2answers
65 views

Input impedance of a non-inverting op-amp

From what I've read (and simulated), the feedback loop of an op-amp modifies the input impedance of the non-inverting input. The value specified in the datasheet is the open-loop input impedance, and ...
0
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0answers
30 views

Buck Converter power supply based on astable oscillator and zener diode feedback?

simulate this circuit – Schematic created using CircuitLab I've asked several theoretical questions about this before, but I've assigned values and changed my circuit quite a bit. The ...
0
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0answers
55 views

Modelling a BJT with easy equations, but having false scenarios

NPN: simulate this circuit – Schematic created using CircuitLab ...
1
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1answer
30 views

Feedback in hybrid power supply

During my research of PSU I came across schematic from Linear's datasheet: 1) Whats the purpose of node which is going from output to SW pin of buck converter? 2) Is node which provides 6V ...
0
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1answer
64 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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3answers
51 views

Error in op-amp integrator due to delay in attaining second summing point constraint

An op-amp in negative feedback forces both inverting and non-inverting inputs to the same value. But this takes some time which as per my knowledge is few nanoseconds. So won't this time delay cause ...
0
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1answer
27 views

Why should I bother with Frequency Response calculations in a Spilt-rail buck regulator design?

I'm looking at an existing implementation a split rail step-down power supply (application report). I would like to know what's the big deal with frequency response in the reference design? I think ...
0
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2answers
55 views

How does a negative feedback amplifier reach steady state?

I tried to simulate a negative feedback non-inverting op-amp, and got incorrect results. I ran the following time-stepping code in python: ...
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2answers
79 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 ...
0
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4answers
126 views

Understading negative feedback [duplicate]

There is a question here about something similar, but it's asking about the internals of an op-amp. I'm having trouble understanding the function and use despite several hours of YouTube tutorials. ...
2
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2answers
55 views

Why does the feedback resistor change?

I'm looking at a reference design from TI : 18-Bit, 1MSPS Data Acquisition Block (DAQ) Optimized for Lowest Distortion and Noise On page 19, you'll find the following image. It describes the ...
0
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1answer
45 views

How can the flip flop neglect clear when given output is given as feedback?

Here is how the circuet looks. Initally the output the D flip flop is HIGH, when the there is HIGH to LOW input across the multivirator, it create a pulse of 200ms, which is connected to the Clear ...
0
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1answer
97 views

Why does a Colpitts oscillator oscillate at a particular frequency?

The feedback network used in the Colpitts oscillator is an LC circuit is shown below. I understand that the phase difference between the terminals 1 and 3 is 180 degrees. Also the amplifier output ...
0
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1answer
128 views

MATLAB error: “acker” function not returning the same thing as ackermann's formula

I have a discrete time system Suppose I have the following AB matrix of my system $$A = \begin{bmatrix} 0 & 1 \\ 1 & 1.5 \\ \end{bmatrix} $$ $$B = \begin{bmatrix} 0 \\ 1 \\ ...
1
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0answers
111 views

Would this JFET+op-amp circuit work?

This is Figure 9-3(b) from Motchenbacher - Low-Noise Electronic System Design, so I would expect it to work, but I don't understand it: The addition of a discrete common-source stage at the input ...
0
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2answers
139 views

Designing a PI controller for a first order system

I have a first order plant $$ b/(s + a) $$ That I'm trying to control using a PI controller $$ \frac{(K_ps + K_I)}{s} $$ I closed the loop with unity feedback to get this Transfer function ...
0
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2answers
33 views

calculate value for resistor in

I have an LMC6001 op-amp, and I would like to build the ph probe amplifier featured in the datasheet. Unfortunately, I am not sure what R9 is or should be. Does R9 control slew rate? How would I ...
0
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1answer
60 views

OP AMP as active negative resistors

Was reading about OP AMP and saw a article on "Active Negative Resistor" on wikipedia @ http://en.wikipedia.org/wiki/Negative_resistance. Question to the gurus: How practical is this? Can I build a ...
2
votes
1answer
93 views

Intuitive explanation for this hysteresis circuit?

simulate this circuit – Schematic created using CircuitLab I am trying to get an intuitive understanding of this small circuit. I have both breadboarded it to look at behavior on a scope ...
0
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2answers
37 views

Constructing a medical model: logic gates with feedback?

I'm a third-year medical student from Sweden. I am attempting to simulate a specific chain of proteins in a cell using logic gates - specifically, I seek to construct a representation of the ...
0
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1answer
33 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
34 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 ...
0
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0answers
71 views

Preamplifier active volume and balance control

Hello everyone here is a pre-amplifier with active gain and balance controls, now its a derivation of the above circuit but with added resistors for balance control too. Would do formula for the new ...
2
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2answers
161 views

Polarity of feedback for a mosfet circuit

I came across this question in "fundamentals of microelectronics" The objective is to find out the polarity of the feedback. Could someone help me with this? My approach to this question is as ...
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1answer
45 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 ...
0
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1answer
39 views

Optoisolated Feedback Pin Operation

In the case of galvanically isolated AC to DC converters, a controller IC is used to regulate the output voltage of the converter. The feedback pin is fed a signal from an optoisolator driven by the ...
1
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5answers
221 views

Why are feedbacks connected to the negative terminal of op-amps? Example given

I ask this because when I do the nodal analysis for the OP amp in figure 3, I end up with the same results as the inverting amplifier, even though the inverting terminal in figure 3 is grounded. So ...
2
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4answers
171 views

How do crystal oscillators work with feedback consisting of CMOS inverters?

For a crystal oscillator to work, there must exist a feedback path with properly designed specifications in order for all to work as expected. Broadly, the basic form of this control system is as ...
0
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2answers
202 views

Why there is many configurations of Colpitts oscillator?

I would like to understand how colpitt's oscillator works but I'm confused because there are many configurations on the internet and I don't know what is the difference between them. For the next two ...
0
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2answers
94 views

Feedback loops and Logic Gates

Setup: a simple 3 bit incrementer that is both connected to a digital display and to itself simulate this circuit – Schematic created using CircuitLab Assuming that there is no clock to ...
1
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1answer
107 views

Generating pseudo-random numbers with restricted hardware

I have a need to generate a 448-bit value that appears random, for use in a test circuit. The "randomness" of the values is not overly important; the size of the generator hardware is. I am using an ...
0
votes
0answers
46 views

Analyze circuit [duplicate]

I asked an INCOMPLETE question and ask again. In the schema below, the input signal comes from a magnetic sensor. The amplitude of the signal is about 0.7 V and the period is 100 Hz. 4066 connect ...
0
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2answers
86 views

Can one always drive oscillator inputs with a single-pin oscillator output and bypass the integrated feedback circuitry?

Very little is written in the MCP2211 datasheet regarding the oscillator input configurations. The microcontrollers I have been using lately allow you to use the self-powered, single output ...
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1answer
99 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 ...
0
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3answers
249 views

Why is a gyrator negative feedback?

Consider this circuit, this is a gyrator and acts like an inductor. Why when we analysis this circuit do we use assume negative feedback (i.e. the voltage at each input is the same). I thought that ...
-1
votes
1answer
89 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 ...
1
vote
1answer
59 views

How can one seperate the negative feedback types one from another?

Like voltage shunt, voltage series, current shunt, current series. I can seperate them with opamps or box diagrams very well(its easy i guess) but when it comes to a point that we use real transistors ...
0
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0answers
65 views

Op Amp Low Pass Filter - Feedback not connected as expected?

I have come across a circuit which I think is an active low pass filter, but it seems to have a few differences from the standard circuit I am used to seeing. Referring to the schematic, I am not ...
2
votes
4answers
188 views

Why isn't IC1 a comparator?

This is with reference to a circuit i saw in The Art of Electronics.The authors claim that IC1 is an integrator and that the circuit ensures that a current of magnitude |Vin|/(200k) constantly flows ...
0
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3answers
121 views

How does an op-amp become stable in this circuit?

i simulated the circuits in an mobile app. below is another circuit with negative feedback -I understand how the second circuit works(-ve feedback) but the problem is with the first circuit -Here ...
1
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1answer
94 views

Facing to real world feedback designs (here, Constant Current Generator)

I still work on a current generator made with 2 opamps and a nMOS. If I find the bias point to understand how much my LED can be driven, I still have problems to find an affordable way to derive the ...
1
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3answers
430 views

Modifications to 555 LED Fade Circuit

I was looking for a circuit to fade an LED on and off using no microcontrollers, and found this nice circuit: http://www.555-timer-circuits.com/up-down-fading-led.html it seems like exactly what I ...
0
votes
1answer
317 views

How do I detect servo stall with an Arduino?

I am controlling a standard 5-volt servo with an Arduino with PWM. My objective is to rotate the servo until it physically gets stalled (feels resistance) and then stop. Then I want the Arduino to ...
2
votes
1answer
103 views

Effect of zeroes in system stability

Suppose we have two third order systems (a and b), with three poles and two zeroes,poles for both the systems are at the same positions in frequency domain but these systems differ in the placement of ...
0
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2answers
119 views

Generating a high speed single-ended voltage output from differential currents

I'm working on a signal generator using a high speed DAC, which has balanced current outputs (two outputs, each 0-20mA, 180 degrees out of phase). The DAC is 250MSPS, so I'd like the analog frontend ...
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2answers
102 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 ...
1
vote
4answers
554 views

Stability and loop gain of negative feedback systems

When we look for stability of a feedback system, why do we only concentrate where loop gain is unity and check the phase margin there. The phase of the closed loop system might be passing through 180 ...
1
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2answers
69 views

What is the correct transfer function of a feedback loop if the summing amplifier has different input resistors?

Suppose I have a circuit below: simulate this circuit – Schematic created using CircuitLab I know the the transfer function of a negative feedback loop is: ...
5
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2answers
308 views

Why do we compensate PWM controllers?

I have been studying switch mode power supplies for a while. I have understood the working principle of several common topologies But there is a detail in the control circuit structures which I still ...