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Homework Help: A small thing about diodes

  1. Mar 31, 2010 #1
    The following picture represents the current/voltage graph through a basic p-n junction diode.

    500px-Diode-IV-Curve.svg.png


    Diodes have a built in potential 0.6 volts. One must overcome this potential to make the diode work. This 0.6V are the nearly flat line in the forward region. Am I right?

    My question is:
    If you connect a diode in a closed circuit with resistance and a battery (+5V), then would Kirchoff work this way?

    0 = 5V - 0.6V - 4.4V

    Is the diode simply -0.6V?

    And one more thing, what happens if the battery is only +0.5V?
     
  2. jcsd
  3. Mar 31, 2010 #2

    berkeman

    User Avatar

    Staff: Mentor

    You are correct. And if the battery is only supplying 0.5V, then you are still on the right side of the plot before Vd, so very little forward current flows.
     
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