Problem with AD620 Amplifier - Pressure Sensor Signal Amplification

Discussion in 'General Electronics Chat' started by Kevin Mark, Mar 20, 2016.

  1. Kevin Mark

    Thread Starter New Member

    Mar 20, 2016
    4
    0
    I am trying to map the Pressure sensor output voltage which in mV to Volt scale. The pressure sensor output is connected to the AD620's pin 2 & 3 and I am taking the output from pin 6. While making the circuit I am facing two problems.

    My question has two parts

    Part 1: How to connect -5v and +5v to this IC? I mean how to make -5v or is it just connected with ground? I am not able to understand this part. I have tried using a LM7805 and I gave AD620's +vcc [+5v] to incoming +5V which is connected to LM7805 pin 1 and connected pin 3 to AD620's -vcc [-5v]. The ground of LM7805 [ pin 2] is connected to Ad620's ground. Please tell me if I am doing it wrong.

    Part 2: For the experiment purpose, I have taken -5V and +5V from the FG and connected it to AD620 and tested the circuit. The output of AD620 is pretty weird, I am getting either 1.47v [max] output or 0.77v [min]. I am confused
    1. Why the minimum voltage is not 0.00v ?
    2. Why output is not varying according to the input? I have been expecting to get a range of voltage not just some max and min voltage and nothing in between?

    [​IMG]
     
  2. Picbuster

    Member

    Dec 2, 2013
    373
    50
    please supply sensor spec's/datasheet allowing us to help you.
     
  3. crutschow

    Expert

    Mar 14, 2008
    12,973
    3,219
    Post your circuit diagram.
     
  4. ericgibbs

    Senior Member

    Jan 29, 2010
    2,499
    380
    hi,
    Look at Fig35 of the datasheet for single supply operation, note the connection required on Pin5, the Vref pin.
    E.
     
  5. Kevin Mark

    Thread Starter New Member

    Mar 20, 2016
    4
    0
  6. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,762
    1,099
    Wrong link for sensor datasheet.
     
  7. Kevin Mark

    Thread Starter New Member

    Mar 20, 2016
    4
    0
    Use this link for the datasheet. If you click on the link you will be able to download the PDF of the datasheet
     
  8. bertus

    Administrator

    Apr 5, 2008
    15,634
    2,342
    Hello,

    Wich of the sensors do you use?
    There are more types in the datasheet.

    Bertus
     
  9. Kevin Mark

    Thread Starter New Member

    Mar 20, 2016
    4
    0
    I had been using MPS 2000 Pressure sensor but I couldn't find any datasheet related to that. Sorry, The closest is the one that I have posted.
     
  10. bertus

    Administrator

    Apr 5, 2008
    15,634
    2,342
Loading...