instrumentation Amplifier

Discussion in 'General Electronics Chat' started by ALA, Jun 4, 2005.

  1. ALA

    Thread Starter New Member

    Jun 4, 2005
    1
    0
    Hello,
    Could anyone tell me what are the restrictions when calculating a typical instrumentation amplifier (3 OPAMP's) cause I've have one which auto-oscilates and I don't understand how to avoid it.
    I've realized that the values of the resistances change the amount of oscilations, but I want to obtain a gain at least 50 times V2-V1.

    Any tutorial or link about it would help me, Thank you.

    A. L. A.
     
  2. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Ordinarily an instrumention amplifier is stable. Is it possible for you to provide a schematic of the circuit hookup?

    For any amplifier to oscillate requires the existence of very specific feedback conditions.

    Hopefully one of our members can spot something by examining your schematic.

    hgmjr
     
  3. mozikluv

    AAC Fanatic!

    Jan 22, 2004
    1,437
    1
    hi,

    yes it would be best if you can show your schem. however am just curious, is your feedback resistance beyond 500k? if it is then that is your probable cause of instability. :D
     
  4. m.desigan

    New Member

    Oct 25, 2006
    1
    0
    Instrumentation Amplifier
     
  5. Søren

    Senior Member

    Sep 2, 2006
    472
    28
    Hi,

    Did you decouple the supply properly ?
     
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