RLC Circuits

Discussion in 'Homework Help' started by AnthonyWDJr, May 20, 2012.

  1. AnthonyWDJr

    Thread Starter New Member

    Mar 8, 2012
    3
    0
    Quick question, look at the attached circuit. At 500 Hz the calculated impedance phase is -88.2 but when you measure across R1 (channel B) in comparison to the input (channel A) you read 88.2. Why is the measured reading 180 out? Any help would be appreciated.

    Thanks,

    Tony D. RLC.jpg
     
  2. jasperthecat

    Member

    Mar 26, 2009
    20
    0
    Tony

    Is the oscilloscope triggering off A or B Channel ?
     
  3. steveb

    Senior Member

    Jul 3, 2008
    2,433
    469
    You are not measuring impedance, but you are measuring voltage at a point. Use the voltage divider rule and you'll see the total series impedance is in the denominator. Do out the math and you'll see the oscope is correct.

    Also, note that you are not a full 180 deg out from what you expect. It's actually 176.4 deg.
     
    Last edited: May 20, 2012
Loading...