precision rectifier

Discussion in 'Homework Help' started by shruthi kashyap, Nov 18, 2011.

  1. shruthi kashyap

    Thread Starter New Member

    Nov 18, 2011
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    can any one tell me why the word precision is used in precision rectifier and what is the difference between precision rectifier and the normal rectifier... it`s urgent
     
  2. MrChips

    Moderator

    Oct 2, 2009
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    3,371
    A simple rectifier circuit uses a diode. The input voltage has to exceed the turn-on voltage (0.6V for ordinary Si diode) before rectification is achieved.

    A precision rectifier is an active circuit using an opamp and a diode in the feedback loop. This overcomes the turn-on "knee" voltage.
     
  3. Wendy

    Moderator

    Mar 24, 2008
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    2,536
    To add to what MC said, this is useful for test equipment, where eliminating extra variables is required.
     
  4. crutschow

    Expert

    Mar 14, 2008
    13,056
    3,245
    The op amp reduces the turn-on voltage of a diode in its feedback loop by a factor equal to the open-loop gain of the op amp. For practical op amp gains this reduces the forward voltage to a fraction of a mV, thus giving a "precision" or near ideal diode characteristic for the rectifier function.
     
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