1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Sinusoidal waveform issue

  1. Oct 15, 2009 #1
    I was routinely checking a question in an Engineering Maths book as listed below:

    The instantaneous value of voltage in an a.c.
    circuit at any time t seconds is given by
    v = 100 sin(50[tex]\pi[/tex]t - 0.523) V. Find:
    (a) the peak-to-peak voltage, the periodic
    time, the frequency and the phase angle
    (b) the voltage when t = 0
    (c) the voltage when t = 8ms
    (d) the times in the first cycle when the voltage
    is 60V
    (e) the times in the first cycle when the voltage
    is =-40V
    (f) the first time when the voltage is a maximum.
    Sketch the curve for one cycle showing
    relevant points. [(a) 200 V, 0.04 s, 25 Hz,
    29.97° lagging (b) -49.95V (c) 66.96V
    (d) 7.426 ms, 19.23 ms (e) 25.95 ms, 40.71 ms
    (f) 13.33 ms]

    Questions (d) and (e) are the one of interest to me, I worked those two questions and my answers were as follows:

    (d) 7.43 ms, 12.57 ms
    (e) 25.95 ms, 34.05 ms

    I have highlighted the discrepancies between my answers and the authors answers. Who is correct ? A cursory glance at second answer of part (e) would show an issue as the periodic cycle is 40 ms so how could it fall out of the first cycle. Is there a different way of calculating negative voltages also. Thanks, any detailed explanations / corrections would be appreciated
     
  2. jcsd
  3. Oct 15, 2009 #2

    berkeman

    User Avatar

    Staff: Mentor

    Welcome to the PF. Could you please show the way you solved the equation for d) and e)? That would be the quickest way for us to check your math.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Sinusoidal waveform issue
  1. TTL waveform (Replies: 2)

  2. Energy waveform (Replies: 13)

Loading...