Dc bias for adc

Discussion in 'The Projects Forum' started by Jonesy, Mar 31, 2011.

  1. Jonesy

    Thread Starter New Member

    Jul 7, 2010
    20
    0
    How do one bias an AC signal to a DC signal to be measure by an ADC which only accepts positive voltages?
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
  3. Jonesy

    Thread Starter New Member

    Jul 7, 2010
    20
    0
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    If we have the full requirement, it makes it easier to suggest a solution.

    That converter should work fine, if it gives you the precision you need.
     
  5. Jonesy

    Thread Starter New Member

    Jul 7, 2010
    20
    0
    measuring an AC 60Hz sine wave current using a current transformer.
    Need 1mV/1mA sensitivity.
     
  6. someonesdad

    Senior Member

    Jul 7, 2009
    1,585
    141
    You could use an op amp for the offset (i.e., add a DC voltage to the AC waveform).
     
  7. Jonesy

    Thread Starter New Member

    Jul 7, 2010
    20
    0
    I try not to use opamp as I do not have positive and negative supplies which the opamps need.

    I tried using the cap followed by a voltage divider, the cut-off is at 15Hz which is well below my 60Hz, blocking the DC component. But tried it on breadboard, it stays at the same voltage no matter what AC signal i couple in. Maybe my voltmeter could not measure this correctly.
     
Loading...