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Homework Help: Diode Switching Characteristics

  1. Jun 21, 2010 #1
    1. The problem statement, all variables and given/known data

    We are given a peak-to-peak voltage of 10. I am attempting to explain the following characteristics:

    1) With a larger forward bias (and a corresponding smaller reverse bias), the storage time increases.

    2) With higher frequency, the storage time decreases.

    2. Relevant equations

    1) The largest storage time is associated with the largest forward bias voltage.
    In terms of storage time: (Vf=9 & Vr=-1) > (Vf=5 & Vr=-5) > (Vf=3 & Vr = -7)

    2) Keeping Vf and Vr constant, increasing the frequency decreases the storage time.

    3. The attempt at a solution

    1) Based on my understanding, a larger forward bias means that larger excess minority carrier concentrations are supported at the space-charge edges of the diode. Thus, it takes longer for the minority carrier concentrations at the space charge edge to reach thermal equilibrium values (aka longer storage time).

    2) Based on my understanding, a higher frequency means that the diode switching is taking place at quicker intervals. As such, at higher frequencies, less time is given for the excess minority carrier concentrations to build up at the space charge edges, correlating to shorter storage time.

    Confirmation/corrections to my solutions are much appreciated - thanks in advance for your help!
  2. jcsd
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