need help.. about emg

Discussion in 'The Projects Forum' started by terabyte, Nov 28, 2013.

  1. terabyte

    Thread Starter New Member

    Mar 3, 2012
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    i was be told by using the LM741Cn the circuit will not working its tru or not.. i have made a emg circuit by using lm741cn, until now the circuit not working,... i really frustrated by troubleshoot for many time.. need help
     
  2. terabyte

    Thread Starter New Member

    Mar 3, 2012
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  3. MrChips

    Moderator

    Oct 2, 2009
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    Correct. LM741 opamp is a poor choice. It is 40 years old and past its best due date.
    Select a modern instrumentation amplifier that provides high CMRR.
     
  4. terabyte

    Thread Starter New Member

    Mar 3, 2012
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    thank you for read my thread..
    can give some example..
     
  5. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    op37, opa365, ca3240, tlc272, lm358 are just a few.....
     
  6. #12

    Expert

    Nov 30, 2010
    16,261
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    Making R1 and R2 not match seems the wrong thing to do. U2 and U3 seem to be drawn wrong because they are just square wave generators the way they are drawn now. The labels on the capacitors are difficult to read. One of the worst difficulties with the LM741 is the dead zones near the power supply voltages, but no power supply voltages have been listed.

    Fixing these things will make this easier for the rest of us.
     
  7. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Check out this video and this video. The guy mentions specific ICs to use. I have no idea how good his advice is, as I haven't tried out his circuit yet. I am also interested in EMG signal processing. I have just ordered EMG sensors that should arrive tomorrow. Maybe in the near future I will have more practical advice for you.
     
  8. terabyte

    Thread Starter New Member

    Mar 3, 2012
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  9. terabyte

    Thread Starter New Member

    Mar 3, 2012
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  10. terabyte

    Thread Starter New Member

    Mar 3, 2012
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    value capaciot is 100nano and 50 nano
     
  11. #12

    Expert

    Nov 30, 2010
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    The input labels on U2 and U3 are backwards.
    You fixed the resistor network properly then labeled the amplifiers backwards.
     
  12. terabyte

    Thread Starter New Member

    Mar 3, 2012
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    can you tell me, how voltage input and frequencies that electrodes detect
     
  13. terabyte

    Thread Starter New Member

    Mar 3, 2012
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    i already take your advice but it still same.. i also change the op amp to lm 358p.. still not working.. please help any circuit that suitable so that i can continue my final project.. the due date are near..
     
  14. #12

    Expert

    Nov 30, 2010
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    I see about 8 Hz to 700 Hz.
     
  15. terabyte

    Thread Starter New Member

    Mar 3, 2012
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    can i make ina118 concept by using lm358N.. on my electronics market.. i do not found any ina118 or ina128
     
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