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Homework Help: Wien Bridge Help

  1. Sep 15, 2018 at 11:59 AM #1
    1. The problem statement, all variables and given/known data

    When testing the circuit of FIGURE 1 (a) it was found that the output shown in FIGURE 1 (b) was obtained when the input was connected to ground.


    explain why this was so and attempt an estimate of the capacitance values of C.

    2. Relevant equations

    3. The attempt at a solution
    estimating the waveform as 7ms the formula f = 1/T was used to get the frequency of 142.857Hz

    assuming C1 = C2 and R1 = R2

    the formula f = 1/2πCR was used, rearranged into C= 1/2πfR to give capacitance as 111uF.

    any help is much appreciated in giving me any advice as to whather this is correct.

    Attached Files:

    Last edited by a moderator: Sep 15, 2018 at 2:20 PM
  2. jcsd
  3. Sep 16, 2018 at 1:14 PM #2


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    I don't see T = 7 ms
    I count about 10 peaks in the last 30 ms , or about 3&a bit cycles between 20 and 30 ms.
    I see no R!, R2, C1, C2
    The two R values are given and the two capacitors are marked the same, C , so no assumptions needed.
    Ok formula, but I don't get 111 uF, with either your frequency or mine.
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