PIV for Full Wave Rectifier (Quick/Simple)

Discussion in 'Homework Help' started by jegues, Apr 21, 2011.

  1. jegues

    Thread Starter Well-Known Member

    Sep 13, 2010
    I've got a quick question about the PIV.

    Shouldn't it be,

    PIV = 2v_{S} - v_{D}


    This is a full wave rectifier, what he has got looks like what it should be for a Bridge rectifier.

    Which one is correct?

    EDIT: I've got it figured out I was misreading something in the original question.

    It also asks about what fraction of a cycle each diode conducts.

    On any half cycle the supply must overcome a voltage drop of 0.7V.

    wt = sin_{-1}(\frac{0.7}{12\sqrt{2}})

    So the fraction of a cycle that each diode conducts is,

    \frac{\pi - 2wt}{2\pi} * 100 = 12.38%

    Is this correct?
    Last edited: Apr 21, 2011
  2. Adjuster

    Late Member

    Dec 26, 2010
    NB indeed this is not a bridge rectifier: the lost voltage is one diode drop, not two. The calculation in your attachment shows two diode drops, which is wrong.

    Each diode therefore conducts for half a cycle, less the time that the 12V rms AC is less than one diode drop. You seem to have taken the "lost" conduction angle due to the diode drop to be the total. Think again.
  3. jegues

    Thread Starter Well-Known Member

    Sep 13, 2010
    Let wt = \theta

    \theta = 0.0412rad

    \frac{\pi - 2\theta}{2\pi} * 100 = 48.69% \text{  for EACH diode}