Feedback Definition and 239 Threads

Homework Statement Identify 10 feedback systems that you encounter in your everyday environment. For each system, identify the sensing mechanism, actuation mechanism and control computation. Describe the uncertainty with respect to which the feedback system provides robustness and/or the...

Hey everyone, I am an undergraduate mechanical engineering major considering a EE feedback controls course as an upper division elective. I have taken ME Control Systems and am also the Lab Instructor for it this semester. I am familiar with signals, filters, sensors, controllers etc. My...

Well, this post was just calling me out. So my past few posts about transistors, and very good people that replied them, told me that I should embrace this new concept of feedback. We just learned it last week, and I wasn't so excited about it.(meh, just another technique to make transistors...

a magnet rotating a generator attracted to an iron bar, on reaching the iron bar triggers a switch which turns the iron bar to an electromagnet set to repel the magnet which inturn is attracted to the next iron bar and so on. Yes the electromagnet is charged by a battery but if the rotation is...

Feedback loops can be very cheap and can be modified easily by things to produce some interesting photos. I used the attached setup to capture these images over 12 years ago and they are accurate to what you actually see on the screen within the maxed out limits of the hardware/software...

I am trying to understand Type1, 2 and 3 opamp compensators used in DCDC converters. Type 1 is just an opamp integrator. Type 2 has a C in feedback loop with parallel RC. How does this boost the phase Margin? (page 307 - http://tinyurl.com/3qyt5dc) I understand phase and gain margin when...

I'm trying to understand the concept of a control system in electronics. In a control system, we have a substractor, forward path and feedback path. The forward path is described by a function g ( a gain function ) and the feedback by another function ( gain again ). The input is Xi and the...

My system is a compound pendulum hinged at some distance from one end and have a propeller mounted dc motor at the other end. I wish to position the pendulum with the help of motor propeller system. I tried but i am unable to get a mathematical model for it. I am getting a non linear model...

As I watched a few cyclists zoom by today, I started thinking about the mechanics behind the motion of a bicycle. I will now run through the work I have done in analyzing it. Please tell me if I have made any glaring mistakes in my logic and let me know what you think. Purpose Evaluate the...

I'm sure there are many like myself who are self studiers: read the book, do the problems. Right now I'm working through Halliday, Resnick and Walker, Fundamentals of Physics, and doing all the odd problems because the answers are in the back of the book. I'm also watching the MIT OCW lectures...

Hi guys, I need to design a circuit capable of activating a light if there's a sound source. Sound= Light on No sound at all = Light off Here's an attempt (see attachment). The AC voltage source is simulating an audio source. Then i converted it to DC so it could activate both...

I can't understand an opamp circuit whenever there is an active element in the feedback loop. For example, in the current monitor ckt(attached). I don't understand how it works. I can't figure out how the opamp offset and BJT gain would affect the output. This ckt is from national semi AN31.

Hi all, If we misrepresent the Model of the system say we linearized the System Model or any parameter variations like friction, Temp etc. Will normal feedback takes care of the offset of the Model? I was confused with Robust Controller. What is it? and How effective is it than normal...

http://img707.imageshack.us/i/electronicsoscillator.jpg/ Dont know where to start for showing voltage difference at input is zero, suspose its something to do with non idealities of the op amp? For the oscillator question , kinda know how its works; there's positive saturation giving...

Describe velocity feedback damping in relation to aircraft systems? my attempt at an answer: I know what damping is, and i know what velocity feedback is, I just can see how they fit together. I think it's something along the lines of; an auxilery power unit has a speed sensor...

"Resume" website... would love some feedback! Hello to all, It's coming to be about that time when I'm going to start applying for both jobs and graduate school. Instead of just having a standard resume for jobs, I was thinking of perhaps having something a little bit more interactive and...

Why is the "Grandfather Paradox" considered a paradox? Feedback exists in other disciplines, so why not in physics? Isn't disallowing feedback in time akin to stating that a negative feedback system can never exist in nature? (And, yet, they obviously do!) Why not assume that, as in other...

In an inverting opamp let the output be feedback to inverting input through a feedback resistor Rf. We write the direction of flow of current from input terminal to output terminal in the feedback resistor Rf. But if this direction is correct then how can we say that input is fed back?? it seems...

what is the meaning of feed back in electronics? thanks.

http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys1821.html

Hello Say I'm reading a (scientific) book, and find all these small errors in it (typos and stuff, nothing serious). Is there anyone to send a list of all these errors, for the benefit of future printings? (does anyone care?) Thanks

Dear SA/Ms: I am seeking feedback from active and inactive SA/Ms regarding both the current and possible future utility (if any) of BRS. I have two multiple choice questions; due to limitations of VB software I must apparently create two different polls to ask them. This poll contains...

So, I'm trying to prove that \lim_{x \to a} f(x) = \lim_{h \to 0} f(a+h) and I'm wondering if this "proof" is correct: Suppose that \lim_{x \to a} f(x) = l and \lim_{h \to 0} f(a+h) = m with l \neq m. Then, for any \varepsilon > 0 there must be some \delta > 0 such that 0 < |x-a| < \delta...

A concept for strong negative feedback in Climate? I have been following some of the more interesting concepts in climate model theories for a couple years. Svenmark's cosmic ray theory in "The Chilling Stars", Svensmark and Calder, is very interesting. Miskolczi's theory of strong...

can anyone explain quasar feedback.. having some trouble.

One of the conditions for oscillation is that the (regenerative) feedback loop must provide a 180 degree phase shift. This is due to the fact that, for a regenerative effect, the signal must undergo n*360 degrees phase shift: 180 from the amplifier and another 180 from the feedback network...

NOTE- Images are thumbnails, click to enlarge Homework Statement Show that the positive feedback gain expression for the circuit below is v2/v0 = 1/[3 + j(wL/R - R/WL)] (anything in red I added to the original problem) Homework Equations (above)The Attempt at a Solution Along with the below...

I'm just wondering, if an op-amp is connected in a positive feedback configuration, should the output not saturate immediately? Here is an example circuit i made in pspice along with its input/output curve (V12 has amp of 3v). http://img689.imageshack.us/img689/1286/posfeedback.png As...

Homework Statement http://img24.imageshack.us/img24/9028/72841137.jpg Homework Equations Routh-Hurwitz Stability Criterion The Attempt at a Solution For first question, you just write the Routh Array, make sure that the first row is all positive and you get Kmax = 1. Simple enough How...

Homework Statement What is relay feedback? I have to use it to create an automatic tuner for the differential, integral, and proportional gains in a PID control. Homework Equations The Attempt at a Solution

Hi All, In my control systems lectures my professor talks about feedback changing the 'topology' of the system. Is he just talking about the structure of the block diagram changing, or is there some link to the topology which mathematicians refer to Regards, Thrillhouse86

As promised in the now closed CRU-hack thread, this is intended to show why I am convinced that the cause for global warming is overstated and that changes in use of fossil fuel and CO2 production will have little effect on climate. I will try and stick to the scientific method, no room for...

A block of mass m slides down an incline plane of length xL. The friction factor b is constant, where the friction force increases as a linear function of forward velocity v. This produces exponential motion. My problem in building an educational simulator is this, I want to compute the time...

What is feedback? what is the advantages of it?

Hi my name is Matt. I'm preparing to take my PhD qualifying exam which consists of a 25 minute PowerPoint presentation with oral questioning to follow. If anyone has a few minutes and would like to take a look and offer comments or questions it can be viewed at...

While introducing negative feedback, my book gave the following example: Let the signal voltage be 101mV and the output voltage of the amplifier be 10V Out of this 10V a fraction (0.01) i.e. 100mV was made to feedback to the input circuit. The feedback circuit did not introduce any phase...

Hello, I was just wondering if anyone has used the software Mathematica 7. I heard it's a really good program and with the new functions it looks great, i was just wanted to get some good user feedback from people who definitely know what they're talking about. Thanks! P.S. - as a side note...

{I wrote this a while ago, thought i would share. I know it's not complete, far from complete actually, but if there's enough interest I'll finish it in notime...heak i might even write more expand the index.} INDEX TECHNIQUES OF INTEGRATION 1)Direct Use of Formula 2)Numerical Integration...

ok so if we have an amplifier with direct negative feedback we have a voltage follower if we put a resistor between that inverting input pin and ground, we can do these things: if we put another resistor between the output and the inverting input we can adjust the gain if, instead, we...

Looking at the equations for the gain of a common cathode tube amplifier with the cathode resistor unbypassed (though the question in general could apply to similar configurations with BJTs and FETs) I see that the gain of the amplifier is something like \frac{\mu R_{l}}{R_{p} + R_{k}(\mu +1) +...

Hi, I started to design a simple circuit and want to ask you what you think about it. http://img152.imageshack.us/img152/8508/circuit.th.png Basically what I have is a motor that can be turned on with a switch and can run for 5 more seconds when the switched is turned off. The coil...

Hi guys, I have a brief I wrote up about black holes and energy transfer across the event horizon. I want some feedback - which forum group should I put it in? Pete

I want a MATLAB code to draw the root locus for a characteristic equation of a transfer function of unity feedback, also what is the range of K that keeps the system stable , here is the characteristic equation: s^5+600s^4+50000s^3+ks^2+24ks+80k=0 please help, thanks in previous

One of the key factors in determining the climate sensitivity to the increasing atmospheric concentration of CO2 and other long lived greenhouse gases is the response of water vapor to the relatively small warming induced by these gases. Climate models produce a strong signal of positive water...

Hello all I have come across a circuit of a standard differential amplifier with an integrator in one of the feedback paths. I have no idea what its function is. I suppose some sort of frequency gain discrimination Any ideas? Matheinste

Hey, 1. Homework Statement . I wrote my own proof for the below, I was wondering if you guys could take a look at it and give me some feedback please. Particularly, I would like to know if this proof is rigorous enough. Lemma 2.4 - Suppose f has a second derivative everywhere, and that...

Hey, I have the following standard feedback system: http://img112.imageshack.us/img112/7152/feedbacksystemuq5.jpg This shows the Z-Transform where: A(z) is the z transform for input a[n] and C(z) is the z-transform of the system's output c[n]...

Please if you are willing to help give me feedback and check for mistakes, post ! I have three essays to do in the next 2 weeks or so. The first is about the New Deal The second essay is a philosophy essay the third essay is about media and how it affects us Thanks in advance !

Hello Chaps, I have been thinking about for a bit and the texts i have are quite vague on the topic. I'd like to know what monitoring devices are used for the control rods. I would have to assume that power output or neutron detection is used for this purpose? Cheers, Rhys

Hi everyone, I have a small MATLAB problem which arose while trying to solve a full state feedback problem in control theory. I have a system in state variable form \dot{x} = Ax + Bu y = Cx where u = -Kx, so the system reduces to \dot{x} = (A-BK)x The solution is x(t) =...