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Help with this circuit

  1. Jun 3, 2010 #1
    Hi everyone i got project from someone

    Here is the Project
    Code (Text):
    www.stanford.edu/class/ee122/Spice_Decks/pspicedemo.pdf
    And i did the same what the pdf file tells

    Here yall can see the video which i made

    Code (Text):
    [URL]http://rapidshare.com/files/390247187/CaptureWiz005.wmv
    [/URL]

    Or

    Code (Text):
    http://www.youtube.com/watch?v=4G82E2uDP2A
    But rapidhsare one's quality is good


    Circuit Pic
    qnwryx.png


    kcb040.png


    The graph which i want to invert
    1jx734.png

    Can someone help me with inverting the graph?
    What should i add in the circuit to invert the graph?
     
    Last edited by a moderator: Apr 25, 2017
  2. jcsd
  3. Jun 3, 2010 #2

    dlgoff

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    Welcome to PF.

    The circuit you have is called a http://en.wikipedia.org/wiki/Low-pass_filter" [Broken].
     
    Last edited by a moderator: May 4, 2017
  4. Jun 3, 2010 #3

    uart

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    I think he's probably referring to inverting the amplitude, since it's an "inverting" amplifier topology.

    To sheheryarnoor: Just plot the phase response and you'll find it's already "inverted" (as in 180 degrees phase shift in most of the pass band). What you have plotted there is a frequency response "magnitude". The magnitude will always be positive, you need to plot the phase to confirm whether it's "inverting" or not.
     
  5. Jun 3, 2010 #4
    i made a circuit like this 2lvfnu8.png
    But it gives me error.Isn't it same like high pass filter?i think it is but it is still giving me error
    Can anyone make a video tutorial for me please
    I need it for my friend he is in the hospital:(
     
  6. Jun 3, 2010 #5

    dlgoff

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    This is an inverting amp with a gain of A=R2/R1. i.e. Vout=AVin
     
  7. Jun 3, 2010 #6
    can anyone of u make a video tutorial of it for me?
    or just draw a circuit even in Paint so i can know how the circuit will look like and what components there will be
    Please i wanna help my friend he is in the hospital
     
  8. Jun 3, 2010 #7
    You need to connect the positive side of Vin to C1 and the negative input to ground -- right now you've got the negative side of Vin connected to C1 and an open circuit on the positive side. And also remove the voltage source on the output, and put your probe here.
     
  9. Jun 4, 2010 #8
    i removed voltage source and connected as u said
    n654pg.png

    But the graph shows like this then

    24c9j0w.png
     
  10. Jun 4, 2010 #9
    When I said "the positive side" I meant the terminal that has a "+" sign next to it. The negative side has a "-" sign next to it. I'm not sure what you're trying to do anymore, but in your last attached picture (which I guess is supposed to be an "integrator"):

    1) Connect the positive output of Vin (marked with a + sign) to the 1k resistor and the negative side to ground.

    2) Connect the negative input of the opamp to the node where the resistors and capacitor meet, and the positive input of the opamp to ground.


    If your input signal is a square pulse train, what do you expect to get on the output?
     
  11. Jun 4, 2010 #10
    98yk5z.jpg

    30w72hd.png

    See the red lines i want graph like those red lines the red lines have been sketched in Paint to give me a clue that what graph will look like
    Can u make like these?
    Actually i am not a student of Electronics i am doing it for my friend he is in the hospital so i wanna help him
    Please help me to help him
     
    Last edited: Jun 4, 2010
  12. Jun 4, 2010 #11

    dlgoff

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    Oops. Actually it is a high pass filter. I didn't see the capacitor at first. Sorry. The corner frequency = 1/2πR1C1 with a bandpass gain of R2/R1.
     
  13. Jun 5, 2010 #12
    lol as i told u am not a student of electronics just helping my friend
    So i dont know what are u talking abt?:p
    Can u make a graph like the red line?
     
  14. Jun 5, 2010 #13

    vk6kro

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    You can combine low pass and high pass filters to get passbands like that one.

    [PLAIN]http://dl.dropbox.com/u/4222062/low%20pass%20high%20pass.PNG [Broken]

    Here R2 and C1 form a low pass filter to produce the slope from 10 KHz upwards and
    C2 and R1 form a high pass filter to produce the slope from 1 KHz downwards.
     
    Last edited by a moderator: May 4, 2017
  15. Jun 6, 2010 #14
    what is this triangle thing which u have used?
    GND Analog?or what?
     
  16. Jun 6, 2010 #15
    "vk6kro" Can u make a video of it?I tried to make a circuit like u have shown but mine graph was change it wasn't like urs
    So i wish u make a video of it
     
  17. Jun 6, 2010 #16

    vk6kro

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    The triangle is a ground symbol.

    Not sure what sort of video you mean. Why would you do that?

    Are you plotting with LT Spice 4?
     
  18. Jun 6, 2010 #17

    uart

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    "My friend's in hospital and the only thing that will cure him is a video of the simulation of a band-pass filter"

    Man you've gotta give this guy the award for most creative excuse of why someone else should do my homework/assignment for me. :rofl:
     
  19. Jun 6, 2010 #18

    vk6kro

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    Hopefully his friend will have a speedy recovery and be able to do his own homework. :)

    I'm sure we all wish him well.
     
  20. Jun 7, 2010 #19
    i mean get a screen recorder and when u make a circuit record it and then upload it to utube so i can see what did u do and what did i do wrong
     
  21. Jun 7, 2010 #20
    i mean make a circuit and graph like u have showed in ur pics
    While making them make a video of it
    Record ur screen by screen recorder so i can know what did i do wrong?
    Upload it to youtube or rapidshare then
    Can u do it please
     
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