Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Feedback

  1. Feb 22, 2017 #1
    What's the feedback for an op amp? And tell me the formula.
     
  2. jcsd
  3. Feb 22, 2017 #2

    davenn

    User Avatar
    Science Advisor
    Gold Member

  4. Feb 22, 2017 #3
    Thank you for this video. And I need formula to find the frequency.
     
  5. Feb 22, 2017 #4

    davenn

    User Avatar
    Science Advisor
    Gold Member

    what frequency ?
     
  6. Feb 22, 2017 #5
    The output wave's frequency.
     
  7. Feb 22, 2017 #6

    davenn

    User Avatar
    Science Advisor
    Gold Member

    it's going to be the same as the input, why do you think it would change ?

    consider ... if I am using an op-amp as a microphone preamplifier, the last thing I am likely to want is the frequency to be changing


    Dave
     
  8. Feb 23, 2017 #7

    LvW

    User Avatar

    When applying feedback to an amplifier, we send a certain part of the amplified output signal back to the input - and superimpose both parts (input and feedback signal).
    In most cases, we make use of NEGATIVE feedback where the feedback signal is substracted from the input. This method has many advantages: Bandwidth increase, linearity improvement, gain reduction with reduced sensitivity of the gain value against uncertainties and tolerances of the active element.

    However - as everything in electronics is a trade-off between conflicting requirements - negative feedback has one disadvantage: The stability of the circuit against unwanted oscillations (self-excitement) is reduced. With other words: The stability margin is reduced.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Feedback
  1. Feedback Resistance (Replies: 3)

  2. Feedback oscillator (Replies: 12)

  3. Motor Feedback (Replies: 6)

Loading...