very low voltage ac to dc

Discussion in 'General Electronics Chat' started by abdulmajeeth, Feb 12, 2009.

  1. abdulmajeeth

    Thread Starter New Member

    Feb 12, 2009
    2
    0
    Hi

    I want to convert 0- 250 mv 10 Hz ac signal to 0-25 mv DC signal and fed to a A/D.

    If I use diode to rectify then loss of signal due to very low voltage.Any method??

    Can any one help with circuit?
     
  2. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    1) run your signal through an amplifier

    2) run the amplifier output through a precision rectifier

    3) sample the precision rectifier output via a voltage divider.
     
  3. abdulmajeeth

    Thread Starter New Member

    Feb 12, 2009
    2
    0
    Thanks for your input.
    If we amplify,noise also getting amplified.
    any better solution
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    You may need a lock-in amplifier that can operate with a noisy signal.
     
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