Low pass filter and gain calculation

Discussion in 'Analog & Mixed-Signal Design' started by sohamkul, Jun 27, 2016.

  1. sohamkul

    Thread Starter Member

    Jun 24, 2016
    43
    2
    Hello everyone,
    I am working on a data acquisition system project . I have used SMPS power supply and two pressure sensors(-5V to +5V input) and (0-20mV o/p)
    my analog circuit consists of one op-amp(OP07) and one instrumentation amplifier(AD620)
    Output of circuit after signal conditioning is given to 16 bit ADC (ads1115).
    output of sensors show lot of fluctuation so i have used this low pass filter (Image attached)
    if anyone could please explain how this filter works and what is GAIN of this filter it would be of immense help.

    Thank you .
    ca296b3a-273c-4322-a9d9-9b0a4d4c7e89.jpg Hello everyone,
     
  2. crutschow

    Expert

    Mar 14, 2008
    13,056
    3,245
    Yes it has negative feedback, but the input is the (+) op amp input, so it's a non-inverting amp with a gain of (1 + R16/R17) = +2.
     
    sohamkul likes this.
  3. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,546
    1,252
    As Wally said, the gain is +2.0 at DC. Shteii, why do you think the gain is -1?

    OP: Where did you get this circuit, and what does the source say about its gain and frequency response?

    ak
     
    sohamkul likes this.
  4. shteii01

    AAC Fanatic!

    Feb 19, 2010
    3,399
    497
    My error.
     
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