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Negative and postive feedback.

  1. Oct 18, 2011 #1
    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 even more complicated).

    But when I actually went to study it, I found it VERY interesting and very useful technique(or consequence, i don't know how to call it :D).

    I have fairly few simple questions.


    Is this site legit, or as mr. Claude would call it heresy ?

    http://www.opamp-electronics.com/tutorials/feedback_3_04_10.htm" [Broken]

    If not, read on:

    [PLAIN]http://pokit.org/get/663797f99b52fd6474a1a901e3a0088a.jpg [Broken]

    See that feedback resistor?

    I understand that it controls the transistor's amplification coefficient(not as much as common-collector bias).

    But here is what bothers me:

    if I put this feedback resistor, do I with resistance control what portion of output signal I am transferring to base-emitter voltage?

    Ie. If I had very small feedback resistor, would I transfer too much of output signal to input, and distort the whole thing?

    I have more questions, just I want to clear this for start.

    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Oct 18, 2011 #2


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    Same link as in other thread. First read section 2.2, then section 5.6.
    http://www.stanford.edu/class/ee122/Handouts/EE113_Course_Notes_Rev0.pdf [Broken]

    I think those notes are really good. Nice of Stanford to provide them.
    Last edited by a moderator: May 5, 2017
  4. Oct 18, 2011 #3
    Thank you, I'm on it.
    Last edited by a moderator: May 5, 2017
  5. Oct 18, 2011 #4


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    Actually, I think I have my sections wrong. I got confused because they only give section numbering inside the document.

    I meant. First 14:2.2, page 218 and 219.
    Then 5.8: page 67 to 74. Especially look at the feedback diagram on page 73.
  6. Oct 18, 2011 #5

    jim hardy

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    Science Advisor
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    2018 Award

    good for you!

    i am enthisiastic about feedback. once you become aware of it you'll start noticing how Mother Nature uses it everywhere. She LOVES a balance.

    will read your link tonite.

    meantime, for feedback in nature and a break from electronics::


    note very last comment....
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