What is Feedback: Definition and 245 Discussions

Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop. The system can then be said to feed back into itself. The notion of cause-and-effect has to be handled carefully when applied to feedback systems:

Simple causal reasoning about a feedback system is difficult because the first system influences the second and second system influences the first, leading to a circular argument. This makes reasoning based upon cause and effect tricky, and it is necessary to analyze the system as a whole.

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  1. maverick280857

    MATLAB How to Plot a Symbolic Function in MATLAB for Full State Feedback Problem?

    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) =...
  2. C

    Feedback Resistance: How Much to Use?

    http://sales.hamamatsu.com/assets/applications/SSD/si_pd_circuit_examples.pdf The picture 5. Usually, how much the feedback resistance to use? 100u ohms?? or, how do we know how much resistance to use? thank you.
  3. B

    Transfer Function & Unity Negative Feedback Control System

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  4. maverick280857

    Control Systems Project Closed Feedback Image Focusing

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  5. N

    NOT Gate Feedback: Explaining Output Voltage Changes

    If I have a simple TTL NOT gate and had a feedback line from the output to the input, then how would I explain what happens to the output voltage for certain inputs? Does it just simply oscillate continuously?
  6. T

    Resume Feedback, Mechanical Engineering student

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  7. M

    Good textbooks for feedback control systems

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  8. F

    Feedback potentiometer circuit QUESTION

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  9. P

    A question about feedback mechanisms

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  10. R

    Dark matter revealed in video feedback

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  11. B

    Have some ideas looking for feedback

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  12. cepheid

    What causes the feedback (a noise increasing in intensity and pitch)?

    What causes the feedback (a noise increasing in intensity and pitch) sometimes heard when people speak through microphones? I'm sure I have enough background to understand an explanation, I've just never thought about it before.
  13. L

    I am interested in building a rocket with feedback control system

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  14. S

    Understanding Logic Comparators with Negative Feedback: Sam's Confusion

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  15. Andre

    The positive feedback factor of CO2

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  16. B

    Solving Op-Amp with Feedback - Get Help Here!

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  17. E

    Understanding Input and Output Resistances of an Amplifier with Feedback"

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  18. P

    Electrostatics/Electroscope Correct Answers Feedback

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  19. E

    Operational Amplifier with positive feedback problems

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  20. E

    How does positive feedback works in opamp circuits?

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  21. M

    How Do You Calculate the Acceleration and Tension in a Pulley System?

    Homework Statement A 98.6 kg box is resting on a horizontal surface. The coefficients of friction are uk= .1602 and us= .6027 for the surface to box. The box is attached to a 59.1 kg rock by a cord that passes over a frictionless pulley. What is the acceleration of the 59.1 kg mass? Make...
  22. G

    Problem with Electronic Feedback?

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  23. Z

    SPECTRUM video + feedback videos

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  24. L

    Negative Feedback System: Understanding its Practicality

    hey guys. attached is a negative feedback system. This is used to control the system and maintain stability. But something doesn't make sense to me. If you look at the diagram, when the output is y(t)=4sint (as required) then the feedback signal becomes f(t)=2sint, but that means that the...
  25. I

    Inertial Mass Propulsion? Feedback wanted.

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  26. z-component

    Frustrated with eBay Feedback?

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  27. O

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  28. A

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  29. denian

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  30. E

    Id appreciate feedback to develope an idea

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  31. J

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  32. S

    News Is Voting More Destructive Than Not Voting in Representative Democracies?

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  33. C

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  34. J

    Can Negative Feedback Improve Amplifier Performance?

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  35. N

    Univ Physics Courses: EE Major Feedback Requested

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  36. L

    Solving a Problem: Seeking Feedback

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  37. J

    I need some feedback on a strange idea I have. please read post

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  38. E

    How Does Negative Feedback Control Work in the Adrenal Gland?

    How does it work for the 'Adrenal Gland'? I cannot find this information anywhere and I need it as soon as possible, thanks. Thank you.
  39. G

    Solving Shunt Series-Series Feedback Problem: Help Needed | Angelfire

    Hey guys, I am currently solving a problem involving shunt series-series feedback. So far this is what I can say about the circuit: - Series mixing is feedback combined with source - Negative voltage feedback samples output voltage - Series voltage feedback stabilises close loop...
  40. Esnas

    Any High School-Level Activities for Video Feedback and Chaos Theory?

    Some of the high school students where I work have shown interest in video feedback (affine transformations) and fractal geometry. I once saw a video where some people at Georgia Tech (Georgia Institute of Technology) were doing some experimentation with video feedback. I don't know what became...
  41. A

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  42. J

    Give Feedback on Jeremiah Hendricks' Quantum Physics Research

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  43. B

    Interesting paper, require feedback

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  44. D

    Evolutionary Feedback: Random or Feedback from Environment?

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  45. Loren Booda

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