Parasitic capacitance of a bridge rectifier diode

Discussion in 'General Electronics Chat' started by uwed, Jun 19, 2015.

  1. uwed

    Thread Starter Member

    Mar 16, 2015
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    I need to know a good estimate for the parasitic capacitance of a bridge rectifier diode (50/60Hz) roughly in the parameter range 1.2V and 10A. I can't find anything in datasheets. I would like to know if this capacitance is in the range of 10pF or 100pF or 1nF or even higher.
     
  2. #12

    Expert

    Nov 30, 2010
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    datasheet, page 1
    datasheet, page 2
     
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  3. uwed

    Thread Starter Member

    Mar 16, 2015
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    17
    Thank you, a good starting point! Do you think the capacity would increase in case such rectifier diode dies would be in a little power module (diode bridge)? Probably not ... ?
     
  4. #12

    Expert

    Nov 30, 2010
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    A dead diode that is shorted, therefore is not a capacitor, it's a conductor.
    A dead diode that is open is probably still a capacitor.
     
  5. uwed

    Thread Starter Member

    Mar 16, 2015
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    17
    Thank you for the datasheets! That answered my question.
     
  6. crutschow

    Expert

    Mar 14, 2008
    13,006
    3,232
    But probably a much smaller capacitor since an open diode likely means a break in the internal connection so you would not see the normal junction capacitance.
     
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  7. dl324

    Distinguished Member

    Mar 30, 2015
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    Are you talking about reverse biased junction capacitance, or forward? When reverse biased, junction capacitance will decrease with increasing voltage. The opposite happens when forward biased.
     
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  8. uwed

    Thread Starter Member

    Mar 16, 2015
    64
    17
    It is about a simple model of common mode current paths in a converter. So I thought about a parasitic capacitor in parallel to an ideal diode for the diode bridge. But according to comments from crutschow and dl324 it wouldn't work like this? I know there are good spice models available for such a task but for this project I use a simulator that works with ideal diodes and switches.
     
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