Charge Amplifier

Discussion in 'Homework Help' started by Mahathi Anand, Jun 3, 2015.

  1. Mahathi Anand

    Thread Starter New Member

    Jun 3, 2015
    20
    0
    Hello.
    I have been assigned to build a charge amplifier circuit for a piezoelectric sensor required for detecting human pulse. I have several doubts regarding this.

    Im using OPA277 for this and initially I have been trying to build a normal amplifier/integrator circuit. In spite of trying it several times, the output doesnt come right. The value of gain/frequency response aint depending upon the resistor/capacitor value I choose...
    Also, an integrator is supposed to behave as a low pass filter, however, Im able to see high pass characteristics, with a cut off of about 5KHz for any resistor/capacitor value.
    Could you please help me out?
     
  2. crutschow

    Expert

    Mar 14, 2008
    13,056
    3,245
    Only if you post the circuit.
    Otherwise I'm just guessing. :rolleyes:
     
  3. Mahathi Anand

    Thread Starter New Member

    Jun 3, 2015
    20
    0
    This is the circuit. Ive implemented the very same on a breadboard using OPA277
     
  4. crutschow

    Expert

    Mar 14, 2008
    13,056
    3,245
    That's just a generic circuit.
    What are the part values and where is the power?
     
  5. OBW0549

    Well-Known Member

    Mar 2, 2015
    1,328
    890
    We really cannot help you much until you post a COMPLETE schematic, including all component values. Also, it would help to have a link to the product spec (datasheet) of the piezoelectric sensor you plan on using, so we can assess the component value choices you have made.
     
  6. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,546
    1,252
    *A* schematic and *your* schematic are two entirely different things. Guess which one will get you some responses.

    ak
     
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