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Did I build my circuit correct on the bread board (pics)

  1. Jan 11, 2015 #1
    http://imgur.com/Tj3wKiy
    Circuit: http://imgur.com/Tj3wKiy

    What needed to be built.http://imgur.com/6uw12n5
    http://imgur.com/6uw12n5
    [/PLAIN] [Broken]
    The chip being used is an LM741CN.
    Scheme Of Pins can be found here

    Thanks,
    AP
     
    Last edited by a moderator: May 7, 2017
  2. jcsd
  3. Jan 11, 2015 #2
    no you did not wire it correctly, you might also want to put a 22pf cap across r2 to stop high freq oscillations .
     

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  4. Jan 11, 2015 #3

    Bystander

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    Short answer? No.
     
  5. Jan 11, 2015 #4
    Does it have to do with both legs of the 9.1k Ohm resistor being on the same node? I moved one of the legs to the output node.
     
  6. Jan 11, 2015 #5
    better?
     
  7. Jan 11, 2015 #6

    Bystander

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    You're terrifying me with the use of power supply rails for input and output.
     
  8. Jan 11, 2015 #7
    What would be a better option for input? Is my resistance configuration right atleast?
     
  9. Jan 11, 2015 #8

    Bystander

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    You're missing a common connection for the two power supply rails. The 1k end of the voltage divider needs to be connected to that common.
     
  10. Jan 11, 2015 #9

    Bystander

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    Very quick note regarding power for the op-amp: you will generally (not always) be looking for three connections, 1) a positive voltage (+15, or 9 for a 741); 2) a negative voltage (-15); and, 3) a common, ground plane, source reference tying the low end of the positive, and the high end of the negative supply sources together. i.e., two nine volt batteries in series, the positive terminal of one being the positive source, and the negative terminal of the other the negative source, and the connection between the two being the common, ground, reference plane for the circuit.
     
  11. Jan 11, 2015 #10

    davenn

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    closer but still several wiring probs ... am going to try and modify your pic
    be back soon

    Bystander ... the 741 will operate from a single rail PSU :)
     
  12. Jan 11, 2015 #11

    Bystander

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    Been a few years. I'll leave this to you --- you're obviously more "current" on the topic.
     
  13. Jan 11, 2015 #12

    davenn

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    with a single rail you just cannot obtain full swing from 0V to VCC miss by a couple of volts at each end ...


    OK here's a quick (rough) drawing on the same board you used .... don't have a BB with me to do an actual construction and photo

    opamp1.JPG

    for power rails its always good practice to use the + line on one side and the - line on the other side of the board

    you can see there are only 2 jumpers ... 1 from pin 4 to 0V rail and 1 from pin 7 to +V rail

    the 2 wires going off the bottom of the board from pins 3 and 6 are input and output respectively
    you can see the wiring is much less complicated :)

    Dave
     
  14. Jan 11, 2015 #13

    Averagesupernova

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    No different than split supply. The 741 is not a rail to rail op-amp. Makes no difference where the reference is that we call 'ground'.
     
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