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Homework Help: Leading/Lagging and Phasors

  1. May 3, 2008 #1
    1. The problem statement, all variables and given/known data

    Let's say I have
    (1) 6<-9
    (2) 6<189

    I don't have a problem drawing the phasors out, however, I am having a bit of difficulty determining how to 'read' the diagram and tell how one leads/lags the other.

    In the example I've given, I draw out the phasors but when it comes to determining which one lags the other I am a bit confused.

    I can easily find the phase difference (351 - 189 = 162 deg).

    Is there a way I can visually inspect each diagram to determine which one leads and which one lags?
  2. jcsd
  3. May 4, 2008 #2
    Dear jes, -9= 351 its ok but there is 360 degree phase diff (1 full cycle) between them. do u understand my point?

    Suppose, in a perfect circular racing path, u start cycling from 0 degree and round a trip 351 degree and then one of ur frnds starts cycling from -9 degree (means ur 351 degree). At that moment u r lead of ur frnd by 351 degree.

    However, ur answer of the question is:
    Ans: 189 degree leads -9 degree by 198 degree (not 162 degree). (Lets check and discuss with others)
    b fine.
    Last edited: May 4, 2008
  4. May 4, 2008 #3
    Hmm, that's interesting, according to the answer the phase difference should be 162 degrees. I think by convention my book always takes the angle that is less than 180 degrees.

    But anyway, I'm really more interested in figuring out how to look at a phasor diagram and see if one phasor leads/lags the other, I just can't quite tell at this point.
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