Rectifier Voltage Drop

Discussion in 'General Electronics Chat' started by Galibore, Jul 19, 2012.

  1. Galibore

    Thread Starter New Member

    May 22, 2012
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    0
    Hi Guys,

    Is it possible to calculate the voltage drop of a DBR if you know the input VAC? Or is it manufacturer specific?

    Thanks in advance.
     
  2. #12

    Expert

    Nov 30, 2010
    16,247
    6,742
    Read the datasheet. It has a graph of forward voltage drop/current.
     
  3. cork_ie

    Member

    Oct 8, 2011
    348
    58
    If it contains standard silicon diodes, you will generally have about 0.7V per diode. Schottky diodes have a much lower voltage drop C. 0.2V but much higher leakage than silicon. If you have access to a datasheet then that is obviously the best option. If not most multimeters have a Vf setting where you can measure forward voltage
     
  4. Galibore

    Thread Starter New Member

    May 22, 2012
    20
    0
    Thanks guys. Appreciate it!
     
  5. russ_hensel

    Well-Known Member

    Jan 11, 2009
    818
    47
    Rectifiers are often run harder than signal diodes so voltage drops of over a volt are not uncommon. In a bridge you have 2 diode drops. RTFM is almost always good.
     
  6. cork_ie

    Member

    Oct 8, 2011
    348
    58
    1) I work on car alternators every day which have silicon diodes often carrying up to 30A and have never seen a diode drop more than 0.8 V.
    0.7V is a pretty standard value for the IN series and most bridge rectifier diodes are similar.
    2) Yes you are correct each diode will have a voltage drop so an overall drop of 1.5 V or so can be expected. Power dissipation of the bridge must also be considered e.g. 3 Amp rectifies will produce circa. 9 Watt.
     
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