RC Frequency Phase-Shift Calculation

Discussion in 'Homework Help' started by JDR04, Sep 17, 2012.

  1. JDR04

    Thread Starter Active Member

    May 5, 2011
    339
    4
    Hi Folks, revisiting this one.

    I've attached the information I have on this question. What I don't understand is how the 50 and the 5 are derived in the formula. I think the 5 is derived from the fact that there are 5 wave forms in total with the circuit but am not sure.

    I can easily apply the formula as it is but would like to understand what I am doing and why.

    I think forum member WBahn would have an interest in this one as he previousely offered some wise advice to me.

    Your help will be appreciated and thanks again......JDR04
     
  2. ecesoul

    New Member

    Sep 8, 2012
    8
    0
    f=1/(2 x pi x R x C x sqrt(6))
    this become 50/RC..may be some rough practical approximation

    5k x 0.05microFarad = 5 x .05 ? might be wrong
     
  3. JDR04

    Thread Starter Active Member

    May 5, 2011
    339
    4
    Might be,but I cant find any reference to it on the internet. My tutor is away as well so I cant get any help there either.Anyway thanks.-JDR04
     
  4. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    5,448
    782
    A detailed analysis of your oscillator is well established in the literature.

    It can be shown after a good deal of algebra that

    f_{osc}=\frac{1}{2\pi R C \sqrt{6+4\frac{R_C}{R}}} \  Hz

    If [as in your case] Rc=R then

    f_{osc}=\frac{1}{2\pi RC \sqrt{10}}=\frac{0.0503}{RC} \ Hz

    if R is in kΩ and C is in uF then

    f_{osc}=\frac{50.03}{RC} \ Hz
     
  5. JDR04

    Thread Starter Active Member

    May 5, 2011
    339
    4
    Thanks t n k. It's all way above my level at the moment but I'll go through it bit by bit and see if I can make sense of it.

    Thanks for your time and input- JDR04
     
  6. JDR04

    Thread Starter Active Member

    May 5, 2011
    339
    4
    Sorry, I meant to ask t n k. So the formula given in the text is a short cut in this situation. In any other type of phase shift frequency calculation the proper formula to use is the one supplied by you in you post.

    Am I understanding this properly so far? Thanks again - JDR04
     
Loading...